DRY MIXTURE IN PARTICULATE FORM FOR PREPARATION OF AERATED FOOD PRODUCTS

The present invention relates to a dry mixture in particulate form for preparation of aerated food products. The invention further relates to a method for preparation of aerated food product using the composition of the invention. The invention further relates to aerated food products obtainable by the method of the invention.

BACKGROUND OF THE INVENTION

Many food products like beverages and other liquid food products can be prepared by the addition of water to a powder mixture to dissolve or disperse the powder mixture and prepare the liquid food products. Examples of this are instant soup powders: a consumer takes some powder for making instant soup, mixes this with hot water, and the soup is ready for consumption. This is a very simple way to prepare a simple, hot food product. Other examples are well known, such as instant tea powder mix, instant coffee powder mix, cocoa powder mix, and soy-based beverage powder mix.

Generation of gas bubbles upon addition of water to a dry mixture is also well known. Examples of this are for example instant cappuccino powders. Various publications describe dry powders that release gas when they are mixed with water to create beverages ("gas release agents"). These powders can be used to create a foam layer, for example to produce a cappuccino-like foamy, frothy layer on top of coffee. For example WO 2006/023564 A1 relates to a soluble foaming composition, and in particular a foaming protein-free composition.

Various publications describe the effect of thickeners on the creaming of gas bubbles in beverages. For example WO 2013/034520 A1 relates to edible powder compositions which, upon mixing with a liquid, form a foam beverage. Various publications describe dry powders that release gas upon dissolution in water, and that contain an oil or fat dispersed in the matrix of the particles.

WO 2008/002139 A1 relates to a powdery additive for beverages, such as a cappuccino foamer. The additive contains unhydrogenated palm kernel stearin. WO 2006/022540 A1 relates to a powdered , cold-water soluble/dispersible, foamable composition. The composition may contain medium chain triglyceride (MCT) oil.

EP 1 627 572 A1 discloses a method for increasing the foaming capacity of powder compositions. The powder may contain a dispersed fat.

WO 01/08504 A1 relates to a soluble foamer ingredient which, upon addition of a liquid, induces the formation of or forms a foam. The powder may also contain a fat.

Also dry powders that release gas upon dissolution in water and that contain emulsifiers are known. WO 2010/071425 A2 relates to a foaming composition or foamer for use in cold beverages and other instant foodstuffs. The particles may contain fat, carbohydrate, protein, and may be coated with lecithin.

WO 98/07329 relates to a powdered creamer which is soluble in cold water. The particles may be coated with lecithin. The phospholipids in lecithin generally have a HLB-value lower than 8.

EP 1 797 772 A1 describes a self-foaming liquid culinary aid, comprising a first liquid component comprising an aicd, and a second liquid component comprising an edible salt for the preparation of food products wherein gas bubbles are dispersed throughout the bulk of the products (e.g. aerated yoghurt or jam).

EP 1 228 694 relates to an aromatizing agent comprising granules formed of particles of a foaming agent and particles and/or droplets of an aroma compound agglomerated with an agglomerating agent. The particles of a foaming agent comprise a matrix containing carbohydrates and protein and entrapped gas.

US 2001/04121 1 relates to a water soluble creamer, used as cold beverage creamer, which comprises edible oil, sweetener, protein, and an emulsifier in specific

proportions. The creamer contains an entrapped gas, which causes foaming upon dissolution in a beverage component, but does not contain added dairy-derived components.

US 2005/287276 relates to a powdered beverage composition for sustained

carbonation in an aqueous environment, the composition comprising a microcapsule comprising a core comprising a component selected from the group consisting of acids, bases, effervescent couples, and mixtures thereof; and a water-insoluble permeable encapsulation barrier coating the core, the encapsulation barrier comprising an edible polymeric material.

WO 2008/046698 relates to a food composition comprising gas bubbles and, based on the food composition, water, protein, gas, fibre particles, and surface active particles, wherein the gas is air, nitrogen or a combination thereof. WO 94/12063 relates to a food product selected from the group of low-fat spreads, dressings, cheese and sauces, comprising gas cells having a thermodynamic stability in excess of 2 weeks and more than 90% by number of the gas cells having an average D3,2 particle size of less than 20 micrometers. The gas cells have a surface comprising edible surface active materials.

Powdered instant compositions for preparing such food products would be

advantageous, for instance in view of shelf-life. However, no commercially available instant powdered products are known. SUMMARY OF THE INVENTION

In spite of the various types of gas release agents that have been described, improvements are possible, in particular in relation to the organoleptic properties of a food product which is prepared with the use of such gas release agent. Therefore the objective of the present invention is to provide aerated food products having improved organoleptic properties, in particular an improved mouthfeel, that are appreciated by consumers. In particular, the present invention aims to provide an instant powder composition for preparing a food product, in particular a beverage, another liquid food product or a spoonable food product, with satisfactory organoleptic properties, which food product contains gas bubbles dispersed in the bulk of the product and wherein the gas bubbles remain in bulk within a time period which is long enough for the consumer to consume the food composition. More in particular, it is an object to provide such a composition which after reconstitution in an aqueous liquid forms an aerated product wherein gas bubbles are dispersed in the bulk of the product, which product imparts a creamy mouth-feel, in particular a mouth-feel resembling fat globules, when consumed.

We have met this objective by providing a dry composition in particulate form that can be used for preparation of an food product containing gas bubbles upon the addition of water. The dry composition contains an instant flavour component to prepare the food product, and a water-soluble or water dispersible gas release agent in particulate form that releases gas bubbles upon reconstitution in water. This gas release agent is at least partially coated with a lipophilic compound and/or an amphiphilic compound having a HLB-value of at least 8. The food product preferably is a beverage or liquid food product, which contains dispersed gas bubbles in a continuous liquid phase. The bubbles form a dispersed phase and are dispersed by combining the specific gas release agent and one or more other instant food components, in particular a flavour component.

The coating of the gas release agent leads to improved organoleptic properties, as the gas bubbles are smaller as compared to gas release agent without a coating. Moreover the gas bubbles are better retained in the bulk of the food product, instead of creating a foam layer on top of the product. These are organoleptic properties that are

appreciated by consumers, not only because of the sensation given by the presence of bubbles but also in that the product may impart a creamy mouthfeel, in particular a mouth-feel resembling fat globules. The smaller gas bubbles are, the more they resemble the oral sensation of fat or cream globules. Further, the invention is in particular advantageous in that it allows the preparation of a fluid food product wherein bubbles remain dispersed in the bulk, and which food product preferably has a creamy mouthfeel, at a relatively low viscosity of the product. To this effect, the composition in the form of a dry mixture in particulate form preferably comprises a hydrocolloid, preferably a hydrocolloid of which a solution or dispersion in water shows thixotropic behaviour.

Further, the invention provides a powder composition for preparing a food product (fluid or spoonable) wherein bubbles remain dispersed in the bulk, wherein the concentration of the hydrocolloid, contributing to maintaining the bubbles in the bulk for a prolonged time, is relatively low to obtain a dispersion-stabilising effect, compared to for instance a thickening agent, such as starch, disclosed in WO 2013/034520 A1 . Further, the invention is advantageous in that it may have an enhanced taste or smell, compared to a similar product wherein the bubbles are absent. Thus the concentration of flavours, such as salt or sugar, or aroma's may be reduced to impart a similar taste or scent sensation.

Hence in a first aspect the present invention provides a composition in the form of a dry mixture in particulate form for preparation of an aerated food product containing dispersed gas bubbles in a continuous phase, the dry mixture in particulate form comprising:

- an instant flavour component in particulate form;

- a hydrocolloid in particulate form, wherein the hydrocolloid provides an apparent yield stress of at least 0.3 Pa within a period of 30 seconds after mixing with water to reconstitute the hydrocolloid, wherein the hydrocolloid comprises xanthan gum;

- a water-soluble or water dispersible gas release agent in particulate form, containing voids wherein pressurised gas is entrapped, that releases gas bubbles upon reconstitution in water,

wherein the gas release agent is at least partially coated with a lipophilic compound and/or an amphiphilic compound having a HLB-value of at least 8.

In the purview of the present invention, the instant flavour component is suitable to prepare a food product selected from the group of:

- soups, bouillons, sauces, gravies, and/or seasonings;

- other savoury food products;

- tea and tea-based beverages, containing an extract from the plant Camellia sinensis;

- herbal infusions, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these;

- ice cream and/or desserts and/or milk shakes, which are intended for serving at a temperature below 0°C;

- soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein;

- dressings; and

- spreads.

In a second aspect the present invention provides a method for preparation of an aerated food product, comprising mixing a composition according to the first aspect of the invention with water. In a third aspect the present invention provides A food product containing gas bubbles in the continuous phase, obtainable by the method according to the second aspect of the invention.

The present invention also provides a method for preparing a powder composition according to the first aspect of the invention, wherein the gas release agent in particulate form is dry-blended with the flavour component in particulate form.

DETAILED DESCRIPTION

All percentages, unless otherwise stated, refer to the percentage by weight. Gas volumes are given at standard conditions, meaning at a temperature of 20°C and a pressure of 1 atmosphere (1.01325 bar), unless indicated otherwise. Ambient or room temperature is 23 ± 2°C.

Average particle sizes may be expressed as the volume weighted mean diameter D4,3. The volume based particle size equals the diameter of a sphere that has the same volume as a given particle. Alternatively the average particle size may be expressed as the D3,2, which is the Sauter mean diameter. D3,2 is defined as the diameter of a sphere that has the same volume/surface area ratio as a particle of interest.

Savoury food products: these are defined as food products that generally contain kitchen salt at a level of at least 0.5% in a prepared product, and include bouillons, seasonings, mealmakers, hot and cold soups (incl. instant powders for soup), sauces, gravies, meals and sides, cooking aids; these can be sold in different formats including dry, liquid, concentrates, frozen, both for household use as well as professional use. Soups, bouillons: are defined as primarily liquid food products, which may be served warm, cool or cold, and that are made by combining ingredients such as meat and vegetables with stock, juice, water, or another liquid. Soups generally contain kitchen salt at a level of at least 0.5% in a prepared product. The soups and bouillons may be prepared by dissolving an powder mixture in water.

Sauce: a sauce is defined as a liquid, semi-solid food served on or with other foods. Usually sauces are not normally consumed by themselves; they may add flavour, moisture, and improve the visual appearance of a dish. Sauces generally contain kitchen salt at a level of at least 0.5% in a prepared product.

Gravy, is a sauce that is prepared using juices that originate from meat or vegetable during cooking of the meat or vegetable. Gravies generally contain kitchen salt at a level of at least 0.5% in a prepared product.

Seasoning: is a mixture containing spices, herbs, salt, and possibly other ingredients to add taste and flavour to a food dish. Seasonings generally contain kitchen salt at a level of at least 0.5% in a prepared product.

Tea and tea-based beverages: beverages or extracts to prepare beverages, containing an extract from the plant Camellia sinensis.

Herbal infusions: beverages or extracts to prepare beverages, in a similar way as preparing tea or tea-based beverages, without an extract from the plant Camellia sinensis, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these.

Ice cream and/or desserts and/or milk shakes: Food products which are intended for serving at a temperature below 0°C.

Soy-based beverages: beverages containing ingredients originating from soybean, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, and wherein the ingredients comprise a soy protein, preferably at least 0.1 % of a soy protein. Examples of ingredients originating from soybean are soy protein, soy fibre, soy carbohydrate and polysaccharides, and soy oil or fat.

Dressings: these are defined as condiments for mixing with salad, or for serving with other meal components, and includes mayonnaise and light mayonnaise at all fat levels, cold condiments, ketchup, mustard, and salad dressings; dressings may be oil- in-water emulsions. Spreads: these are defined as plastic or liquid margarines at all fat levels (including low fat margarines), water-in-oil emulsion spreads or oil-in-water emulsion spreads, non- dairy spreads and non-dairy creams, and shortenings and structured oils; usually the spreads contain at least one type of vegetable oil or fat.

Dry mixture: relates to a free-flowing powder. This powder may contain moisture, however this moisture generally is not visible to the naked eye.

The term Ό/Τ as used herein refers to lipids selected from triglycerides, diglycerides, monoglycerides and combinations thereof. The oil may be solid or liquid at ambient temperature. Preferably the oil in the context of this invention comprises at least 90 wt% of triglycerides, more preferably at least 95 wt%. In here the term 'fat' is considered to be synonymous to 'oil'. Preferably the oil is an edible oil. Oils may originate from vegetable origin, such as sunflower oil, palm oil, olive oil, and rapeseed oil. Alternatively the oil may originate from animal origin, such as dairy fat, butter oil, and fish oil. The oil may be modified by fractionation, may be chemically or

enzymatically interesterified, or may be fully or partially hardened.

The 'HLB value' is a well-known classification of surfactants or mixtures of surfactants, as defined in W.C. Griffin, 1949, Classification of surface-active agents by HLB. J. Soc. Cosmet. Chem. 1 : 31 1 -326. The HLB value is given by the equation HLB = 20*Mh/M, where Mh is the molecular mass of the hydrophilic part of the molecule and M is the molecular mass of the whole molecule thus giving a value on an arbitrary scale of 0 to 20.

'Aerated' means that a composition contains dispersed gas bubbles. The gas phase may be any gas that is used in the context of food products, such as air, oxygen, nitrogen, carbon dioxide, nitrous oxide, or mixtures of these. Preferably the gas comprises air, nitrogen, or carbon dioxide. Hence the term 'aeration' is not limited to aeration using air, and encompasses the 'gasification' with other gases as well. The extent of aeration is usually measured in terms of 'overrun', which is defined as: volume of aerated product - volume of initial mix

overrun = ^χ

Volume of initial mix where the volumes refer to the volumes of aerated product and unaerated initial mix (from which the product is made). Overrun is measured at atmospheric pressure. In a first aspect the present invention provides a composition in the form of a dry mixture in particulate form for preparation of an aerated food product containing dispersed gas bubbles in a continuous phase, the dry mixture in particulate form comprising:

- an instant flavour component in particulate form;

- a hydrocolloid in particulate form, wherein the hydrocolloid provides an apparent yield stress of at least 0.3 Pa within a period of 30 seconds after mixing with water to reconstitute the hydrocolloid, wherein the hydrocolloid comprises xanthan gum;

- a water-soluble or water dispersible gas release agent in particulate form, containing voids wherein pressurised gas is entrapped, that releases gas bubbles upon reconstitution in water,

wherein the gas release agent is at least partially coated with a lipophilic compound and/or an amphiphilic compound having a HLB-value of at least 8.

In the purview of the present invention, the instant flavour component is suitable to prepare a food product selected from the group of:

- soups, bouillons, sauces, gravies, and/or seasonings;

- other savoury food products;

- tea and tea-based beverages, containing an extract from the plant Camellia sinensis;

- herbal infusions, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these;

- ice cream and/or desserts and/or milk shakes, which are intended for serving at a temperature below 0°C;

- soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein;

- dressings; and

- spreads. In a preferred embodiment, the food product has an organoleptic property that is appreciated by consumers, not only because of the sensation given by the presence of bubbles but also in that the product may impart a creamy mouthfeel, in particular a mouth-feel resembling fat globules, when consumed. One of the advantages of the present invention is that the coating on the gas release agent provides small gas bubbles, smaller than without a coating.

Preferably the food product is a beverage or a liquid food product, and the continuous phase preferably is a liquid continuous phase.

Further, the invention is in particular advantageous in that it allows the preparation of a fluid food product wherein bubbles remain dispersed in the continuous liquid phase and do not create a foam layer, and which food product preferably has a creamy mouthfeel, at a relatively low viscosity of the product.

Gas release agent

The gas release agent may be any gas release agent which conforms to the requirements as defined in the present definition of the invention. A gas release agent typically comprises a solid matrix material (i.e. solid at least at 25°C) in which internal voids are present, wherein the gas is entrapped under pressure, i.e. having a pressure of more than 1 .0 bara, in particular of 1 .5 bara or more, more in particular 2-30 bara. In a specific embodiment, the gas pressure is 2.0-10 bara. The solid material may comprise any edible solid material, in particular any substance selected from the group of carbohydrates or polysaccharides, proteins, and emulsifiers, and combinations of these. The solid material generally is a water-soluble or a water-dispersible material.

Particularly suitable as a source for the protein for the solid material of the gas- containing gas release agent are skim milk powder, whey protein concentrate, whey powder, caseinate, and the like. Preferably the gas release agent comprises particles of which the matrix contains a polysaccharide, preferably maltodextrin. The particle matrix preferably contains a combination of protein and polysaccharide. Preferred carbohydrates for the gas release agent include oligosaccharides obtainable by hydrolysing starch (hydrolysed starches), in particular hydrolysed starches having a DE of 10 to 45, glucose syrup, maltodextrins and lactose. nOSA-starch (n-octenyl succinyl anhydride modified starch of hydrophic starch) is another preferred

carbohydrate.

Preferably, the solid material for the gas release agent at least substantially consists of a carbohydrate, in particular a maltodextrin and/or nOSA starch. In a specific embodiment, the carbohydrate content of the gas release agent is 90 to 100% based on dry weight.

Preferably, the solid matrix material for the gas release agent preferably comprises a protein in combination with a carbohydrate, in particular a maltodextrin. The presence of a protein is advantageous at least in some applications in that it may contribute to bubble-dispersion properties of the product.

The gas that is released by the gas release agent upon dissolution may be any gas that is used in the context of food products, such as air, oxygen, nitrogen, carbon dioxide, nitrous oxide, or mixtures of these. Preferably the gas comprises air, nitrogen, or carbon dioxide. Preferably the gas release agent releases at least 1 milliliter of gas per gram of dry gas release agent, at standard conditions. Preferably the amount of gas is such that the amount of gas released ranges from 1 to 100 mL, preferably from 1 to 50 mL, preferably from 5 to 30 mL of gas per gram of dry gas release agent, under standard conditions.

The gas-containing gas release agent particles are typically porous. Usually, such porous particles are prepared by a spray drying technique applying gas injection in a liquid feed to be atomised typically via the use of a high pressure atomisation nozzle. The gas-containing gas release agents may contain particles holding non-pressurised gas (wherein the gas pressure in the internal voids is about 1 bar), such as non- pressurised spray dried foamers. Such foamers are generally known in the art, and described in detail in, for instance, US 4,438, 147 or EP 458 310 A. Good results have been achieved with a gas release agent comprising particles containing a pressurised gas, i.e. having a pressure of more than 1 bar, in particular of 1.5 bar or more. Such gas release agents are e.g. known from WO 2006/023564, EP 2 025 238 A1 and references cited therein. Preferably the gas release agent comprises carbohydrate and/or protein and gas under pressure in voids in the particles.

The gas-containing gas release agent may further contain one or more plasticizers to improve the robustness of the solid matrix material. The presence of one or more plasticizers is in particular preferred for gas release agent containing pressurised gas. If present, the plasticizers are preferably selected from the group consisting of polyols or sugar alcohols, such as glycerol, mannitol, sorbitol, lactitol, erythritol, and trehalose.

Additionally the gas release agent may further include additional stabilizing agents to increase the dispersion stability of the bubbles in the bulk of the food product., to stabilise pH or to prevent protein from flocculation (after reconstitution). Preferred stabilisers are sodium or potassium citrates and orthophophates. Further, a free flowing aid may be present, preferably silicon dioxide or tricalcium phosphate. The gas release agent usually has a loose bulk density of at least 150 g/L. Usually the loose bulk density is 520 g/L or less, in particular in the range of 300 to 500 g/L, more in particular 420 to 470 g/L. A density within this range can be obtained by the person skilled in the art using known technology. For instance use can be made of gas injection into the aqueous feed slurry just before atomisation, which is done preferably with nitrogen gas. This allows preparation of products of such lower densities. Such particles typically have porous structures, in particular containing voids in the range of 1 to 30 micrometer.

Preferably, at least 90 wt% of the coated gas release agent particles (D90) is formed by particles having a size less than 400 micrometer, more preferably essentially all particles have a size of less than 400 micrometer, as determined by a screen test method, using a 400 micrometer screen. Preferably, at least 90 wt% of the coated gas release agent particles is formed by particles having a size of 30 micrometer or more, as determined by a screen test method, using a 30 micrometer (400 mesh) screen. In particular, good results have been achieved with a coated gas release agent having a D10 in the range of 30 to 70 micrometer, a D50 in the range of 100 to 200 micrometer and a D90 in the range of 250 to 350 micrometer.

Preferably the gas release agent contains an emulsifier incorporated in the bulk of the particle, in order to readily disperse the gas bubbles under pressure during preparation of the gas release agent. Preferably the emulsifier has a HLB-value of at least 7, preferably at least 10. Such emulsifier may be a carbohydrate.

The gas release agent is at least partially coated with a lipophilic compound and/or an amphiphilic compound having a HLB-value of at least 8. In here a lipophilic compound is defined as a material which is essentially insoluble in water. In particular essentially insoluble means that the compound has a solubility in water of less than 0.5% by weight at 20°C, preferably less than 0.1 % by weight at 20°C. Preferably the lipophilic compound is from natural origin; and preferably is edible. Preferred lipophilic compounds include fatty acid (provided that the fatty acid is neutral at the pH of the fluid in which the gas release agent is dissolved), triglyceride, phytosterol, phytostanol, phytosteryl-fatty acid ester, phytostanyl-fatty acid ester, wax, fatty alcohol, carotenoid, oil-soluble colourant, oil-soluble vitamin, and oil-soluble flavour. Also combinations of these compounds are within the scope of the present invention. In here an amphiphilic compound is defined as a compound comprising both an hydrophilic group and a hydrophobic group, having a HLB-value of at least 8. The use of these compounds as coating materials, in particular the lipophilic compounds, is surprising, as usually these compounds lead to instability of foams. For example, oils or fats often are used as defoamers.

The gas release agent is at least partially coated with a lipophilic compound and/or an amphiphilic compound having a HLB-value of at least 8, preferably at least 50% of the surface of the particles is coated, preferably at least 75% of the surface of the particles is coated, preferably at least 90% of the surface of the particles is coated, and most preferred at least 98% of the surface of the particles is coated. Preferably the lipophilic compound and/or the amphiphilic compound have a solids content of at least 50% at 20°C, preferably at least 75% at 20°C, preferably at least 90% at 20°C.

Preferably the lipophilic compound comprises oil which is solid at 20°C. If an oil is present, then usually the triglyceride in the oil is a triglyceride of one or more fatty acids having a chain length of at least 6, preferably of 12 to 24. In order to provide a solid coating material composed of one or more triglycerides typically the coating material comprises a sufficient amount of triglycerides that are solid at room temperature, such as saturated C12 to C24 glycerides. Preferred hydrophobic triglyceride mixtures that are solid at room temperature and suitable as coating materials are palm oil, hardened palm oil, butter fat, cocoa butter, coconut oil, hardened coconut oil, and dairy butter fat. Preferably the lipophilic compound comprises palm oil, preferably fractionated palm oil. Also other oils or oil fractions may be used, as long as the oils or oil fractions have a solids content of at least 50% at 20°C, preferably at least 75% at 20°C, preferably at least 90% at 20°C. The coating material as used herein has structural rigidity and resistance to changes of shape or volume at room temperature.

A fatty acid may also be provided as a lipophilic coating material instead of or in addition to a triglyceride, provided that the fatty acid is essentially uncharged at the pH of the fluid in which the gas release agent is dissolved. This is particularly surprising, since fatty acids, like most other emulsifiers such as monoglycerides and diglycerides, are generally considered as detrimental to foam properties, such as foam stability.

The fatty acid salt is usually selected from bivalent metal fatty acid salts, in particular alkaline earth metal fatty acid salts, preferably calcium fatty acid salts and magnesium fatty acid salts. The fatty acid part of the salt is usually selected from fatty acids having 6 to 24 carbon atoms, preferably 12 to 18 carbon atoms. The fatty acid can be an unbranched or branched fatty acid. The fatty acid can be saturated or unsaturated. Other examples of suitable fatty acid salts are sorbates, octanoates, decanoates, dodecanoates, myristates, isostearates, oleates, linoleates, linolenates, ricinoleates, behenates, erucates, palmitates, eicosapentaenoates and docosahexaenoates.

Evidently, the fatty acid salt may be mixture of fatty acid salts. For instance, the mixture may be obtained by saponification of a natural oil mixture, e.g. from coconut oil, palm oil, olive oil or other vegetable oils.

Preferably the amphiphilic compound has a HLB-value of more than 8, preferably at least 9, preferably at least 10. More preferred the amphiphilic compounds has a HLB- value of at least 1 1 , preferably at least 12, preferably at least 13, preferably at least 14. Preferably the amphiphilic compound has a HLB-value of maximally 20, preferably maximally 19, preferably maximally 18. Preferably the amphiphilic compound is selected from the group of amphiphilic sugar esters, amphiphilic esters of

monoglycerides and amphiphilic esters of diglycerides, and amphiphilic esters of fatty acids. Suitable amphiphilic substances in particular include sugar esters and esters of a mono- or diglyceride and an organic acid, and amphiphilic esters of fatty acids. The number of ester bonds may be chosen between 1 and the number of hydroxyl- functionalities of the sugar. Thus, for a sucrose ester the number of ester bonds is in the range of 1 to 8. For the purpose of this invention the term sugar fatty acid ester is intended to include both single compounds and mixtures of single compounds.

Commercially, food-grade sugar fatty acid esters may be obtained from suppliers like Mitsubishi-Kagaku (Tokyo, Japan) or Sisterna (Roosendaal, Netherlands). A preferred mono- or diglyceride ester is an ester of citrate, e.g. citrem® (having an HLB of 1 1 ). Preferred amphiphilic esters of fatty acids encompass lactic acid (including the sodium and/or calcium salts) esters of fatty acids, such as sodium stearoyl-2-lactylate (SSL).

Preferred sugar esters are sucrose esters. The sugar ester preferably comprises a sugar ester selected from the group of stearate esters and palmitate esters. Preferably the amphiphilic compound comprises a sucrose fatty acid ester having a HLB value of at least 8. Preferably the amphiphilic compound comprises a sucrose fatty acid ester having a HLB value of at least 9, preferably at least 10, preferably at least 1 1 , preferably at least 12, preferably at least 13, preferably at least 14. More preferred the amphiphilic compound comprises a sucrose fatty acid ester having a HLB value of at least 15, preferably at least 16. Preferably the amphiphilic compound comprises a sucrose fatty acid ester having a HLB-value of maximally 20, preferably maximally 19, preferably maximally 18. Sucrose fatty acid esters (SFAEs) are a class of emulsifiers that are suitable for food applications. SFAEs may be prepared by the (partial) esterification of sucrose with fatty acids. Since sucrose has eight hydroxyl groups, the degree of substitution obtained can vary from one to eight, thus yielding sucrose monoesters, sucrose diesters, sucrose triesters, etcetera up to sucrose octaesters.

SFAEs can be prepared with any type of fatty acid. Suitable fatty acids may vary both in alkyl chain length and in degree of unsaturation. SFAEs can also be mixtures of different compounds. In one way, mixtures of SFAEs may be mixtures in terms of compounds with a different degree of substitution. In a second way, mixtures of SFAEs may be mixtures of compounds with different types of fatty acids. Mixtures of SFAEs may also be mixtures according to the first and the second ways simultaneously. For example, a SFAE mixture with both palmitic acid and stearic acid residues may for instance comprise sucrose monostearate, sucrose monopalmitate, sucrose distearate, sucrose dipalmitate, monopalmitoyl sucrose monostearate, dipalmitoyl sucrose monostearate, etcetera. For the purpose of this invention the term sucrose fatty acid ester (SFAE) is intended to include both single compounds and mixtures of single compounds according to the above two ways, unless specified otherwise.

Commercially, food-grade SFAEs may be obtained from suppliers like Mitsubishi- Kagaku (Tokyo, Japan) or Sisterna (Roosendaal, Netherlands).

Preferably, at least 72 wt%, more preferably at least 74 wt% of the sucrose fatty acid esters comprises sucrose monostearate or sucrose monopalmitate or a combination thereof. Preferably, from 10 to 90 wt%, more preferably from 20 to 80 wt% of the total amount of the sucrose fatty acid esters is sucrose monostearate. Preferably, from 10 to 90 wt%, more preferably from 20 to 80 wt% of the total amount of the sucrose fatty acid esters is sucrose monopalmitate. Preferably, the combined amount of sucrose fatty acid monoesters and sucrose fatty acid diesters comprised in said sucrose fatty acid esters is at least 75 wt%, preferably at least 80 wt%, more preferably at least 85 wt% and still more preferably at least 90 wt% of the total amount of sucrose fatty acid esters. Preferably the amount of lipophilic compound and/or amphiphilic compound in the gas release agent ranges from 3 to 12% by total weight of the gas release agent, preferably from 4% to 1 1 % by total weight of the gas release agent. Preferably the thickness of the coating ranges from 0.5 to 20 micrometer, preferably from 0.6 to 15 micrometer. More preferred the thickness of the coating ranges from 1 to 10 micrometer.

Hydrocolloid

The composition of the first aspect of the invention may comprise other ingredients. Preferably the dry mixture further comprises a hydrocolloid in particulate form. Such optional hydrocolloid is reconstituted upon addition of water thereby thickening the fluid and entrapping gas bubbles which are released in the liquid by the addition of water to the gas release agent. A liquid is able to suspend gas bubbles if it contains a polymer (hydrocolloid, polysaccharide, thickener, etc.) that can form a weak network, thus providing a sufficient yield stress. The yield stress opposes the buoyancy force, which is responsible for bubbles' creaming in gas dispersions or foams. An increase in the viscosity of the aqueous phase containing the gas bubbles would not be sufficient to stop their creaming but would just slow it down proportionally to the viscosity increase.

The hydrocolloid provides an apparent yield stress of at least 0.3 Pa within a period of 30 seconds after mixing with water to reconstitute the hydrocolloid. Preferably the hydrocolloid provides an apparent yield stress of at least 0.3 Pa within a period of 15 seconds, preferably within a period of 10 seconds after the addition of water to reconstitute the hydrocolloid. Importantly the hydrocolloid develops the yield stress rapidly enough to entrap the gas bubbles that are released by the dissolution of the gas release agent in added water. Preferably the hydrocolloid provides an apparent yield stress of at least 0.5 Pa, preferably at least 0.7 Pa, preferably at least 1 Pa, within a period of 30 seconds after the addition of water to reconstitute the hydrocolloid. More preferred the hydrocolloid provides an apparent yield stress of at least 0.5 Pa, preferably of at least 0.7 Pa, preferably at least 1 Pa, preferably at least 1.5 Pa, within a period of 15 seconds, preferably 10 seconds, after the addition of water to reconstitute the hydrocolloid. Preferably the yield stress that is obtained within a period of 30 seconds is maximally 5 Pa, preferably 4.5 Pa, preferably 4 Pa. Preferably the yield stress that is obtained within a period of 15 seconds is maximally 5 Pa, preferably 4.5 Pa, preferably 4 Pa. The value of the yield stress of the product is the yield stress at 23 °C. The yield stress may be determined based upon the information disclosed herein, in particular in example 10. In particular if the product is intended for consumption at a different temperature, the yield stress preferably also has a minimum or maximum value as mentioned herein at that temperature. Therefore these yield stresses preferably are determined at the temperature of the liquid that is added to the dry particulate mixture.

In particular, good results have been achieved with an optional hydrocolloid, which forms a thixotropic fluid after reconstitution in water, at least in the presence of the other ingredients for the food product, at consumption temperature. In general, a hydrocolloid is preferred that is suitable to provide a thixotropic composition, when reconstituted in water at a temperature of 25°C. Such hydrocolloids are also referred herein as 'thixotropic'. The advantage of using a thixotropic compound, is that it does not give a slimy mouthfeel. Preferably, a solution or dispersion of 0.5 g/L or less of the hydrocolloid in water of 25°C is thixotropic, in particular a solution or dispersion of the hydrocolloid of about 0.2 g/l or less, e.g. about 0.1 g/L. Preferably the optional hydrocolloid has a hydration rate in water at a temperature of 23°C at a concentration of 1 wt% and a volume weighted mean diameter D4,3 of the hydrocolloid ranging from 40 to 200 micrometer, of less than 3 minutes. Definitions of these parameters are provided in WO 2012/030651 A1. The contents of WO 2012/030651 A1 are incorporated by reference.

The hydrocolloid in particulate form comprises a xanthan gum, wherein the xanthan gum preferably has a hydration rate in water at a temperature of 23°C at a

concentration of 1 wt% and a volume weighted mean diameter D4,3 of the hydrocolloid ranging from 40 to 200 micrometer, of less than 3 minutes. Preferably the hydrocolloid has a hydration rate of less than 2 minutes. Preferably the xanthan gum has a hydration rate of less than 2 minutes. Preferably, the hydrocolloid comprises a thixotropic xanthan gum.

Preferably the dry optional hydrocolloid comprises particles having a volume weighted mean diameter D4,3 ranging from about 5 micrometer to 150 micrometer, more preferred from about 10 micrometer to 130 micrometer. Preferably the dry hydrocolloid comprises particles having a volume weighted mean diameter D4,3 ranging from 40 to 200 micrometer, preferably from 50 to 150 micrometer, more preferably from 60 to 90 micrometer. Preferably the dry optional hydrocolloid comprises particles having a Sauter mean diameter D3,2 ranging from 10 to 100 micrometer, preferably from 20 to 70 micrometer, more preferably from 20 to 50 micrometer.

Preferably the optional hydrocolloid comprises a xanthan gum, having the following properties in solution at 23±2°C:

- a hydration rate of less than 3 minutes in a 1 wt% NaCI solution at a 1 wt%

concentration of xanthan gum; and

- an ability to fully hydrate in less than 10 minutes in a 6 wt% NaCI solution at a 1 wt% concentration of xanthan gum. Preferably the hydrocolloid comprises xanthan gum, preferably xanthan gum obtained from the fermentation of Xanthomonas campestris pathover campestris, deposited with the American Type Culture Collection (ATCC) under the accession no. PTA-1 1272. The fermentation requires a nitrogen source, a carbon source and other appropriate nutrients known to the skilled person, and described in WO 2012/030651 A1. The hydrocolloid preferably comprises the xanthan gum as described and defined in

WO 2012/030651 A1. A preferred xanthan gum is Keltrol AP or Keltrol AP-F, supplied by CP Kelco (Nijmegen, Netherlands). Most preferred is the xanthan gum Keltrol AP-F, supplied by CP Kelco (Nijmegen, Netherlands). Advantages of using the preferred xanthan gum, are that the xanthan gum not only rapidly provides the required yield stress, and that additionally the xanthan gum provides this effect independent of the water temperature. Therefore the water temperature for mixing with the dry mixture in particulate form of the invention may have a broad range. Opposite to this, especially native starches mostly need water at high temperature to gelatinise, at least at a temperature above the gelatinisation temperature. Moreover the required amount of the preferred xanthan gum is lower than for example starches of the prior art. The Hydration Rate is determined in the following way, using a hydration rate tester. Hydration Rate is defined as the amount of time for the sample to reach 90% of maximum torque using a torque load cell. While this does not directly measure full hydration, the 90% point is a useful metric for sample comparison. The 100% point obtained is more variable since the approach to the final value is gradual and is affected by even small amounts of random error in the measurement. The instrument utilises a variable speed motor to stir the solvent in a beaker that is mounted to a torque sensing load cell. The xanthan gum is added to the solvent while mixing at a constant speed to begin the test. As solution viscosity builds due to the hydration of the xanthan gum, the torque (twisting force) on the beaker increases. The torque values are continuously monitored by a computer which normalises, prints and plots the data in terms of percentage torque versus time. While torque is not a direct measure of the viscosity of the sample, torque provides a valuable measure of the viscosity development over time.

Hydration Rate Procedure: The test uses 80 mesh particle size xanthan gum, which is dispersed in polyethylene glycol (PEG) at a weight ratio of 3:1 and hand mixed at room temperature (23±2°C). Samples to be tested are mixed with the dispersant immediately before the test is started. Standard tap water is prepared by dissolving 1.0g of NaCI and 0.15g CaCI ₂ -2H ₂ 0 in 1 liter of de-ionised water. A volume of 130 ml. is used in a 250 ml. stainless steel beaker. Xanthan gum is tested at 1 wt%. The stirrer is a H-bar stirrer with the following dimensions: overall length 20.3 cm, length to cross member 17.8 cm, 3.8 cm x 3.8 cm in Ή' (0.64 cm stainless dowel used). The H-bar stirrer has a 2-4 mm clearance from the bottom of the cup in order to mix the solution while maintaining a vortex in the solution. The direction of the Ή' is upright, and a shaft is connected to the 'horizontal bar' of the Ή'. The stirrer speed is set at 600 rpm. The sample is added over a 4-5 second period of time in a very controlled and constant fashion. For consistency and accuracy, the sample must not be added too fast or slow or in an uneven manner. The data are scaled from 0 to 100% of the maximum torque that occurs during the test. The time to reach 90% of maximum torque is taken as the Hydration Rate. This value is found to be stable and repeatable.

If the dry mixture of the invention comprises one or more hydrocolloids, then preferably at least 25 wt% of the total hydrocolloid content in the dry mixture in particulate form is formed by the preferred optional hydrocolloid, preferably one or more thixotropic hydrocolloids, preferably the preferred xanthan gum. More preferred at least 50 wt% of the total hydrocolloid content in the dry powder composition is formed by the preferred hydrocolloid, preferably one or more thixotropic hydrocolloids, preferably the preferred xanthan gum.

The dry mixture in particulate form of the invention may comprise one or more native starches. Preferably the one or more native starches originate from potato. Such native starches may be combined with the preferred optional hydrocolloid as described before. In case such combination of hydrocolloids is present in the dry mixture in particulate form, then less than 25% of the total hydrocolloid content in the dry mixture in particulate form may be formed by the preferred optional hydrocolloid. Preferably the amount of the preferred hydrocolloid according to the invention is smaller than the amount of the one or more native starches. Preferably the total ratio of the amount of preferred optional hydrocolloid, and the one or more native starches ranges from 1 :5 to 1 :10 wt/wt.

The combination of the preferred optional hydrocolloid, preferably comprising a xanthan gum, combined with one or more native starches, is that these hydrocolloids enforce each other's functionality. The concentration of both types of materials can be decreased as compared to their single use.

Dry mixture in particulate form

The weight ratio between the instant flavour component and the gas release agent ranges from 20:1 to 1 :5, preferably from 15:1 to 1 :4. More preferred the weight ratio between the instant flavour component and the gas release agent ranges from 10:1 to 1 :1. The weight ratio between the instant flavour component and the hydrocolloid ranges from 100:1 to 1 :10, preferably from 50:1 to 1 :1 . Preferably the weight fraction of the preferred optional hydrocolloid, preferably the xanthan gum, in the powder composition is at least 0.5 wt%, based on dry weight, preferably at least 1.0 wt%. Preferably the weight fraction of the preferred optional hydrocolloid, preferably the xanthan gum, is usually 5 wt% or less, in particular 4.0 wt% or less, preferably 3.5 wt% or less, more preferably 3.0 wt% or less.

Preferably the weight fraction of native starch if present in the powder composition is at least 5 wt%, based on dry weight, preferably at least 10 wt%. Preferably the weight fraction of the native starch, is maximally 30 wt% or less, in particular maximally 25 wt%.

Preferably at least 50 wt% of the total hydrocolloid content in the powder composition is formed by one or more thixotropic hydrocolloids, more preferably 90 to 100 wt% of the total hydrocolloid content, in particular 95 to 100 wt% of the total hydrocolloid content.

The dry mixture in particulate form according to the invention preferably comprises from 1 wt% to 80 wt% of the gas release agent. Preferably the dry mixture in particulate form comprises from 5 wt% to 70 wt%, preferably from 10 wt% to 50 wt% of the gas release agent.

The dry mixture in particulate form comprises an instant flavour component, to prepare a food product, preferably a beverage or liquid food product. The instant flavour component is suitable to prepare a food product, preferably a beverage or liquid food product, selected from the group of:

- soups, bouillons, sauces, gravies, and/or seasonings;

- other savoury food products;

- tea and tea-based beverages, containing an extract from the plant Camellia sinensis;

- herbal infusions, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these;

- ice cream and/or desserts and/or milk shakes, which are intended for serving at a temperature below 0°C;

- soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein;

- dressings; and

- spreads. Preferably the instant flavour component is suitable to prepare a food product, preferably a beverage or liquid food composition, selected from the group of soups, bouillons, sauces, gravies, and/or seasonings; tea and tea-based beverages, containing an extract from the plant Camellia sinensis; herbal infusions, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these; ice cream and/or desserts and/or milk shakes, which are intended for serving at a temperature below 0°C; and soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein. More preferred the instant flavour component is suitable to prepare food product, preferably a beverage or liquid food composition, selected from the group of soups, and/or bouillons; tea and tea-based beverages, containing an extract from the plant Camellia sinensis; and soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein.

More preferred the instant flavour component is suitable to prepare a food product, preferably a beverage or liquid food composition, selected from the group of soups, and/or bouillons; and tea and tea-based beverages, containing an extract from the plant Camellia sinensis.

Most preferred the instant flavour component is suitable to prepare a soup, and/or a bouillon.

The instant flavour component may contain one or more ingredients which are normally suitable and used to prepare soups, bouillons, sauces, gravies, and/or seasonings; other savoury food products, tea and tea-based beverages, containing an extract from the plant Camellia sinensis; herbal infusions, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these; ice cream and/or desserts and/or milk shakes, which are intended for serving at a temperature below 0°C; soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein; as applicable; dressings; and spreads. These ingredients are known to the skilled person. The dry mixture in particulate form of the invention preferably comprises from 1 wt% to 99 wt% of the instant flavour composition. More preferred the concentration of the instant flavour composition comprises from 5 wt% to 95 wt% of the dry mixture in particulate form. The dry mixture in particulate form is prepared by any method known to the skilled person that is suitable to prepare such dry mixture in particulate form.

Method for Preparing Food Product

In a second aspect the present invention provides a method for preparation of an aerated food product, comprising mixing a composition according to the first aspect of the invention with water. Preferably the food product comprises a beverage or liquid food product. Alternatively the food product, preferably beverage or liquid food product, of the invention is prepared by bringing the dry mixture in particulate form of the invention into contact with another beverage, for example milk, or tea, or soy-based beverage.

Preferably the weight ratio between dry mixture in particulate form and water ranges from 1 :100 to 1 :1 , preferably from 1 :50 to 1 :1. Preferably the weight ratio of gas release agent to water ranges from 1 :200 to 1 :3, preferably from 1 : 100 to 1 :5, preferably from 1 :80 to 1 :10. Preferably the weight ratio of instant flavour component to water ranges from 1 :50 to 1 :1 , preferably from 1 :20 to 1 :1 . Preferably the concentration of the preferred optional hydrocolloid in the food product that is obtained by the method of the invention ranges from 0.1 wt% to 1 wt%, preferably from 0.2 wt% to 0.8 wt%, preferably from 0.4 wt% to 0.7 wt%, and most preferred from 0.45 wt% to 0.6 wt%. The advantage of the preferred optional hydrocolloid is that a relatively low concentration is required as compared to other hydrocolloids.

Preferably the amount of water to the amount of gas release agent, based on the gas volume at standard conditions provided by the gas release agent when all gas is released is at least 1 ml. gas per 100 ml. liquid product (i.e. 1 % overrun). Preferably the ratio ranges from 5 ml. gas per 100 ml. liquid product (i.e. 5% overrun) to 100 ml_ gas per 100 ml. liquid product (i.e. 100% overrun). When the preferred optional hydrocolloid is used in combination with one or more native starches, then preferably the concentration of the one or more native starches ranges from 0.5 wt% to 3 wt%, preferably from 1 to 2 wt%, most preferred from

1.3 wt% to 1 .8 wt% in the food product, preferably beverage or liquid food composition. In case such additional hydrocolloid is present in the dry mixture in particulate form, then preferably the concentration of the optional preferred hydrocolloid in the continuous phase of the food product that is obtained by the method according to the invention ranges from 0.1 wt% to 0.3 wt%, preferably from 0.15 wt% to 0.25 wt% in the food product, preferably beverage or liquid food composition, according to the invention.

Preferably the temperature of the water ranges from 40°C to 100°C, preferably from 60°C to 100°C, preferably from 70°C to 100°C. Alternatively the water may be of a lower temperature, dependent on the type of food product to be prepared. For example some food products are served cold, meaning below room temperature. In that case the water temperature preferably ranges from 0°C to 25°C, preferably from 3°C to 23°C. When the optional preferred hydrocolloid is used in combination with one or more native starches, then preferably the temperature of the water is at least 60°C, preferably at least 70°C.

In another aspect the present invention provides a food product prepared by the method according to the second aspect of the invention. The food product preferably is a beverage or liquid food product. The present invention also provides a food product obtainable by the method according to the second aspect of the invention. The present invention also provides a food product obtained by the method according to the second aspect of the invention.

The food product is selected from the group of.

- soups, bouillons, sauces, gravies, and/or seasonings;

- other savoury food products;

- tea and tea-based beverages, containing an extract from the plant Camellia sinensis;

- herbal infusions, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these;

- ice cream and/or desserts and/or milk shakes, which are intended for serving at a temperature below 0°C;

- soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein;

- dressings; and

- spreads.

The food product preferably is a beverage or liquid food product. Preferably the food product of the invention contains gas bubbles dispersed in the continuous phase, preferably in the continuous liquid phase.

Preferably after reconstitution a composition is obtained which maintains gas bubbles throughout the continuous phase of the product for at least 10 minutes preferably at least 15 minutes, preferably at least 20 minutes, preferably at least 30 minutes.

Preferably after reconstitution a composition is obtained which maintains gas bubbles throughout the continuous liquid phase of the product for at least 10 minutes preferably at least 15 minutes, preferably at least 20 minutes, preferably at least 30 minutes.

Preferably after reconstitution, the gas bubbles constitute from 1 % to 50% of the volume of the dispersion, preferably from 3% to 40% of the volume of the dispersion. More preferred the volume of the gas bubbles ranges from 5% to 30% of the volume of the dispersion, and most preferred from 10% to 20% of the volume of the dispersion. The volume of the dispersion includes the volume of the continuous phase and the volume of the gas bubbles dispersed in the continuous phase. Preferably at least 90% of the gas volume, at least directly after reconstitution, is formed by gas bubbles having a diameter of 200 micrometer or less, preferably 150 micrometer or less. Preferably at least 90% of the gas volume, at least directly after reconstitution, is formed by gas bubbles having a diameter of at least

10 micrometer, preferably at least 20 micrometer. Preferably the gas bubbles have a diameter ranging from 10 to 200 micrometer. Preferably, this is the case for at least 10 minutes, preferably at least 15 minutes, more preferably at least 30 minutes after preparation of the food product. Preferably the food product, preferably a beverage or liquid food composition, is selected from the group of soups, bouillons, sauces, gravies, and/or seasonings; tea and tea-based beverages, containing an extract from the plant Camellia sinensis; herbal infusions, preferably containing an extract selected from mint, camomile, rooibos, rosehip, hibiscus, raspberry, or any combination of these; ice cream and/or desserts and/or milk shakes, which are intended for serving at a temperature below 0°C; and soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein.

More preferred the food product, preferably a beverage or liquid food composition, is selected from the group of soups, and/or bouillons; tea and tea-based beverages, containing an extract from the plant Camellia sinensis; and soy-based beverages, wherein these beverages in reconstituted form contain at least 0.3% by weight of ingredients originating from soybean, wherein the ingredients comprise a soy protein. More preferred the food product, preferably a beverage or liquid food composition, is selected from the group of soups, and/or bouillons; and tea and tea-based beverages, containing an extract from the plant Camellia sinensis.

Most preferred the food product is a soup, and/or a bouillon. Preferably the food product, preferably beverage or liquid food product, is essentially free from added pregelatinised starch, preferably pregelatinised modified starch. If pregelatinised starch is present, the total starch concentration in the liquid food product is preferably less than 0.5 wt%, preferably 0.1 wt% or less. Preferably the beverage or liquid food product according to the invention is essentially free from added

carrageenan. If present, the carrageenan concentration in the liquid food product is preferably less than 0.5 wt%, in particular 0.1 wt% or less. Preferably the beverage or liquid food product according to the invention is essentially free from added guar gum. If present, the guar gum concentration in the liquid food product is preferably less than 0.5 wt%, in particular 0.1 wt% or less.

The present invention also provides a method for preparing a powder composition according to the first aspect of the invention, wherein the gas release agent in particulate form is dry-blended with the flavour component in particulate form. This may be done by any method common to the skilled person.

DESCRIPTION OF FIGURES

Figure 1: Photograph made using coherent anti-stokes raman spectroscopy microscopy of coated gas release agent particles. The fat coating is dark; size of the bar is 50 micrometer.

Figure 2: Photograph made using confocal scanning laser microscopy of a coated gas release agent particle. The fat coating is pointed at by the arrow, bar size is

20 micrometer.

Figure 3: Pictures of two samples from example 6, taken from above, showing the presence or absence of foam layer of on mushroom soup either containing gas release agent particles with 5% sucrose fatty acid ester dispersed in particle matrix (A, top image), or containing gas release agent particles coated with 5% sucrose fatty acid ester (B, bottom image); taken 30 minutes after preparation of the samples.

Figure 4 Graphs showing translation of precision spheres as function of time, experiments from example 10.

10-1 : · HDPE 5.69mm, T HDPE 3.17mm;■ HDPE 3.17mm;♦ PS 4.76mm;

▲ PS 4.76mm.

10-2: · PS 4.76mm; T HDPE 5.69mm;■ HDPE 3.17mm.

10-3: · HDPE 3.17mm (upper curve); · PS 4.76mm (lower curve).

Figure 5 Graphs showing translation of precision spheres as function of time, experiments from example 10.

10-4: · HDPE 3.17mm; T PS 4.76mm;■ HDPE 5.69mm.

10-5: · PS 4.76mm.

10-6: · HDPE 3.17mm, T HDPE 3.17mm;■ HDPE 5.69mm;♦ PS 4.76mm;

▲ HDPE 5.69mm; * PS 4.76mm; · PS 4.76mm.

Figure 6: Graphs showing translation of precision spheres as function of time, experiments from example 10.

10-7: · PS 4.76mm; o PS 4.76mm.

10-8: · PS 4.76mm; o PS 4.76mm

EXAMPLES The following non-limiting examples illustrate the present invention.

Raw materials

• Composition dry instant mushroom cream soup mixes as used (ex Unilever Deutschland, Heilbronn, Germany):

Table 1 Composition of dry instant mushroom soup mixes

• Native potative starch, 9% moisture: ex Sudstarke GmbH (Schrobenhausen, Germany).

• Native Potato Starch Granulated: contains 87% native potato starch and 13% glucose syrup (maize), ex Avebe (Veendam, Netherlands).

• Creamer: contains palm oil and palm oil stearin (76.8%), lactose (6.6%), Na, Ca caseinate (7.8%), potassium phosphate dibasic (1 .0%), glucose syrup (7.8%).

· Xanthan gum: Keltrol AP, Keltrol AP-F, and Keltrol RD ex CP Kelco (Nijmegen, Netherlands).

The particle size distribution of Keltrol AP, Keltrol AP-F powders was determined in house, using a Mastersizer 2000 (Malvern Instruments Ltd., Malvern, Worcestershire, UK), equipped with a Sirocco powder accessory. The average sizes were:

• Modified starches: Agglomerated Prejel VA70, and Eliane SC160 from Avebe (Veendam, The Netherlands). Prejel is a pregelatinised hydroxypropyl distarch phosphate of potato origin; and Eliane is a pre-gelatinised waxy potato starch containing more than 99% amylopectin.

• Gas release agent: Vana-Cappa B01 ex FrieslandCampina Kievit (Meppel, Netherlands). Ingredients of the powder are maltodextrin, modified starch (starch sodium octenyl succinate), and silica free flowing agent. Contains nitrogen gas under pressure, and the gas release is about 22 ml. per gram dry agent upon dissolution in water.

• Palm oil: non-hydrogenated palm oil, Revel A ex Loders Croklaan (Wormerveer, Netherlands).

· Sucrose fatty acid ester : PS 750, ex Sisterna (Roosendaal, Netherlands); fatty acid is mostly a mixture of stearic acid and palmitic acid, HLB-value 16, 75% mono- ester.

• Maltodextrin: ex Roquette (Lestrem, France).

• Lecithins: Metarin and Topcithin NGM ex Cargill (Mechelen, Belgium).

· Hosol: high oleic sunflower oil, ex Cargill (Mechelen, Belgium).

Methodology: Bubble size distribution

A Morphologi G3 measuring microscope from Malvern Instruments Ltd. (Malvern, UK) is used to measure the size and shape of gas bubbles using the technique of static image analysis. Images taken by computer controlled Nikon microscope are analysed by the Morphologi software to provide a bubbles size distribution.

A sample from the middle of a beaker containing a liquid sample with gas bubbles is taken using a plastic pipette. About 0.5 mL is put at one side on a microscopic slide and is spread over it using a specially designed slider in order to obtain a cut off thickness of 0.5 mm. After preparing a sample it is directly placed under the microscope with its magnification set at 2.5x to provide a good overview of the foam bubbles. Randomly, ten images are taken changing the slide position by hand across the whole of its area. It is important to take those images as quickly as possible to minimize the risk of large bubbles collapsing. After scanning all the samples, the image analysis is performed by the Morphologi software. The surface averaged d3,2 value is reported. Example 1 : Coating of gas release agent with palm oil

Gas release agent coated with palm oil: prepared by coating the standard gas release agent Vana-Cappa B01 with palm oil Revel A. This process was carried out in a high shear mixer Cyclomix (ex Hosokawa Micron BV, Doetinchem, Netherlands). The gas release agent starting product was heated to 45°C in the high shear mixer. Then palm oil was added to the gas release agent, as appropriate. The blends were heated to 55°C and mixing was continued for 25 minutes. After 25 minutes of mixing, the powder mixtures were allowed to cool to room temperature. The coated gas release agents contained a palm oil coating which formed either 5%, 10% or 15% of the weight of the powder.

Using CARS (Coherent Anti-stokes Raman Spectroscopy) microscopy it was confirmed that the process resulted in with a fat coating (dark) on at least a substantial part of the surface of the matrix material phase of the gas release agent particles, see also Figure L it should be noted that only the outer part of the powder lights up with this technique, because the laser light does not penetrate further in the powder particles. Also Figure 2 shows an image of another coated gas release agent particle.

Example 2: Coating of gas release agent with sucrose fatty acid ester

Gas release agent was coated with 5% sucrose fatty acid ester. This sample was prepared similarly as described in example 1 . The gas release agent was heated to 55°C in the mixer. Then the appropriate amount of coating material was added to the powder. The blend was heated to 55°C and mixed for 25 minutes. After mixing, the powder mixture was allowed to cool down to room temperature.

Another sample was prepared containing 5% sucrose fatty acid ester in the bulk of the particles of the gas release agent. A dispersion of 95% maltodextrin and 5% sucrose fatty acid ester was sprayed at a temperature of 80°C at a rate of around 100 L/h, with simultaneous injection of nitrogen gas close to the nozzle, at a pressure of about 100 bar. Drying was performed at a temperature of 136°C, followed by 55°C. The density of the powder was around 220 g/liter and the average particle size was around 200 micrometer. Subsequently the powder was loaded with gas by loading a vessel with the dry powder and free flowing agent, pressurising with nitrogen at 35 bar and about 30°C. Subsequently the vessel was heated to above 140°C for at least 15 minutes. Subsequently, the vessel was cooled to about 40°C, and depressurized.

Example 3: Use of the coated gas release agent with instant mushroom soup powder: amount of gas and bubble size distribution

The gas release agent coated with 10% palm oil from example 1 was used in the following experiments.

Dry mixtures were prepared made containing 10 gram of dry soup mix 1 ; 0, 1 , 2, or 4 gram of 10% palm oil coated gas release agent; and 0.2 gram of xanthan gum

(Keltrol AP-F). These powders were well mixed to prepare homogeneous dry mixtures. Immediately thereafter 150 mL of hot water (just after boiling) was added to each mixture and manually stirred for 30 seconds. The total bulk volume (consisting of liquid and gas bubbles dispersed in the liquid) was determined by measuring the total volume as function of time. Therewith the total amount of gas release can be determined. Also the stability of the aerated composition is determined, namely the time it takes that the volume of the gas dispersion decreases due to gas bubble release to the atmosphere. The results are given in the following table.

Table 2 Total volume of aerated instant soup mixture in milliliter as function of time and amount of coated gas release agent (10% palm oil).

volume of dispersion [mL] as function of amount of gas release agent [g] time [min]

og ig 2g 4g

1 161 178 194 222

5 161 175 185 208

10 161 170 180 202

15 160 168 177 198

20 159 166 175 194

25 159 165 174 191

30 159 164 173 189 The average amount of gas released by the coated gas release agent was determined to be 16 ml. per gram.

A further experiment was done by preparing dry mixtures containing 10 gram of dry soup mix 1 ; 2 gram of either palm oil coated gas release agent (according to the invention) or 2 gram of non-coated gas release agent (comparative); and 0.2 gram of xanthan gum (Keltrol AP-F). These powders were well mixed to prepare homogeneous dry mixtures. Immediately thereafter 150 ml. of hot water (just after boiling) was added to the mixture and manually stirred for 30 seconds.

The bubble size distribution of samples taken 2, 7, 12, 17, and 22 minutes,

respectively, after adding water to the dry mixture, was determined. The results are given in the following table. Table 3 Average bubble size (d3,2) of gas bubbles in mushroom soup containing coated (10% palm oil) or uncoated gas release agent.

This shows that the coating of the gas release agent with palm oil leads to decreased bubble size, as compared to uncoated gas release agent. This is advantageous, as smaller bubbles tend to give a more creamy mouthfeel than larger bubbles.

This same experiment was repeated with another batch of coated and uncoated gas release agents. Dry mixtures were prepared containing 10 gram of dry soup mix 1 ; 3 gram of either palm oil (5%, 7.5%, or 10%) coated gas release agent (according to the invention) or 3 gram of non-coated gas release agent (comparative); and 0.2 gram of xanthan gum (Keltrol AP-F). These powders were well mixed to prepare homogeneous dry mixtures. Immediately thereafter 150 mL of hot water (just after boiling) was added to the mixture and manually stirred for 30 seconds.

The bubble size distribution of samples taken at various times was determined. The results are given in the following table.

Table 4 Average bubble size (d3,2) of gas bubbles in mushroom soup containing coated (5%, 7.5%, or 10% palm oil) or uncoated gas release agent.

This shows that in particular during the first 10 minutes the bubble size of the coated gas release agents is smaller. This is in particular interesting, because during this time period the consumer will consume the instant soup mix, when it is still warm. Smaller bubbles are advantageous as compared to bigger bubbles, due to its perceived creaminess.

Another experiment was done with dry soup mix 2. The bubble size distribution was determined of uncoated gas release agent, and gas release agent with sucrose fatty acid ester dispersed in the matrix (from example 2) or coated with 10% palm oil (from example 1 ). Dry mixtures were prepared containing 10 gram of dry soup mix 2; 2 gram of the respective gas release agent; and 0.25 gram of xanthan gum (Keltrol AP-F). These powders were well mixed to prepare homogeneous dry mixtures. Immediately thereafter 150 mL of hot water (just after boiling) was added to the mixture and manually stirred for 30 seconds. The results are given in the following table. Table 5 Average bubble size (d3,2) of gas bubbles in mushroom soup containing coated (5% sucrose fatty acid ester, or 10% palm oil) or uncoated gas release agent. Coated 10% palm oil Uncoated

time [min]

d3,2 [μπι] d3,2 [μπι]

1 170 172

10 172 193

20 200 198

30 212 213

This shows that in particular during the first 10 minutes the bubble size of the gas release agents coated with 10% palm oil is smaller than the size of the bubbles of the uncoated gas release agent.

Example 4: Use of the coated gas release agent with instant mushroom soup powder: retention of gas bubbles in the bulk liquid

Similarly as in example 3, dry mixtures of mushroom soup powder, xanthan gum (Keltrol AP-F) and coated (10% palm oil) gas release agent were prepared. Dry mixtures were prepared made containing 10 gram of dry soup mix 1 ; 3 gram of palm oil coated gas release agent (according to the invention) and various amounts (0, 0.05, 0.1 , 0.15, 0.2, 0.3, 0.4 gram) of xanthan gum (Keltrol AP-F). These powders were well mixed to prepare homogeneous dry mixtures. Immediately thereafter 150 ml. of hot water (just after boiling) was added to the mixtures and manually stirred for 30 seconds.

The total bulk volume (consisting of liquid and gas bubbles dispersed in the liquid) was determined by measuring the total volume of the bulk liquid as function of time. This excludes the volume of a possible foam layer on top of the liquid. Such a possible foam layer would be distinguishable from the bulk liquid by a lighter colour and a clear interface between the bulk liquid and the possible foam layer. The liquid bulk volume is maximally 210 ml_, consisting of 150 ml. water, and 60 ml. gas (20 ml. gas per gram gas release agent). Also the stability of the aerated composition is determined, namely the time it takes that the volume of the gas dispersion decreases due to gas bubble release to the atmosphere. The results are given in the following table. Table 6 Total volume of aerated instant soup mixture in milliliter as function of time and amount of xanthan gum (excluding foam layer on top).

This shows that 0.2 gram of xanthan gum (Keltrol AP-F) leads to good retention of gas bubbles in the bulk liquid.

To determine how much gas is released in total (both retained in the bulk as well as in a foam layer), it was also determined what the total volume of gas release was, and how much retained in the bulk, to determine the effectivity of the xanthan gum. The following table lists these data, taken at 1 minute after adding the water.

Table 7 Total volume of gas released in milliliter (retained in bulk liquid and in foam on top) as well as the volume of the gas bubbles retained in bulk liquid, 1 minute after addition of water.

amount xanthan gum [g] total gas release [mL] gas in bulk liquid [mL]

0 28 0

0.05 44 8

0.1 48 38

0.15 55 44

0.2 53 48

0.3 53 49

0.4 51 45 This shows that when the dry mix contains at least 0.2g xanthan gum (Keltrol AP-F), that most gas bubbles are retained in the bulk liquid, and do not create a foam layer on top. Example 5: Gas release agents with various coating materials

This example provides a hot chocolate type of drink. A powder mixture was made consisting of 17 g of instant chocolate mix (supplied by Heimbs) and 0.3 g of xanthan gum (Keltrol AP-F). To this mixture 3 gram of the following gas-releasing agents were added:

Sample 1 : Gas release agent coated with palm oil, from example 1 .

Sample 2 (comparative example): Gas release agent uncoated

Sample 3 (comparative example): Vana-Cappa B01 gas release agent coated with Metarin lecithin/hosol 1 :1 ratio.

Sample 3 (comparative example): Vana-Cappa B01 gas release agent coated with Topcithin NGM lecithin/hosol 1 :1 ratio.

Sample 3 (comparative example): Vana-Cappa B01 gas release agent containing 10% palm oil dispersed in the powder matrix. Sample 2 was the commercially available Vana-Cappa B01 . Samples 3 to 5 were coated in a fluidized bed at 50°C by spraying 500 gram of the respective lecithin mixture in 20 minutes on 25 kg of the gas release agent. Sample 6 was prepared similarly as the gas release agent containing dispersed sucrose fatty acid ester (as in example 2).

The mixtures were put in glass beakers (250 ml. with a diameter of 60 mm). 150 ml. of water at 85°C was added to each beaker and stirred for 30 seconds. The overruns and foam heights obtained were determined and are given in the following table. Tests were performed about 1 month after production of the samples. At that point in time comparative sample 6 had lost most of its gas. This can be explained by gas leaking through the fat droplets, showing that it was not possible to provide a gas release agent containing a dispersed oil in the particles, which was stable during shelf-life. Overrun and size of foam layer of samples coated with various

The data show that gas release agents coated with fat leads to the formation of a much thinner foam layer on top of the bulk phase. Dispersing gas release agents coated with phospholipids lead to the formation of a thick foam layer on top.

Example 6: Gas release agent coated with sucrose fatty acid ester

The bubble size distribution was determined of uncoated gas release agent, and gas release agent coated with 5% sucrose fatty acid ester and gas release agent with 5% sucrose fatty acid ester dispersed in the particle matrix (both from example 2). Dry mixtures were prepared containing 10 gram of dry soup mix 1 ; 2 gram of the respective gas release agent; and 0.2 gram of xanthan gum (Keltrol AP-F). These powders were well mixed to prepare homogeneous dry mixtures. Immediately thereafter 150 ml. of hot water (just after boiling) was added to the mixture and manually stirred for 30 seconds.

The bubble size distribution of samples taken at various times was determined. The results are given in the following table.

Table 9 Average bubble size (d3,2) of gas bubbles in mushroom soup containing coated (5% sucrose fatty acid ester) or 5% sucrose fatty acid ester dispersed in particle matrix, or uncoated gas release agent.

Dispersed 5% Coated 5% Uncoated

time [min]

d3,2 [μπ\] d3,2 [μπ\] d3,2 [μπ\]

1 143 147 174 10 195 191 183

20 208 202 200

30 195 195 210

This shows that in particular during the first 10 minutes the bubble size of the gas release agents either coated with sucrose fatty acid ester or sucrose fatty acid ester dispersed in the particle matrix is smaller than the size of the bubbles of the uncoated gas release agent. This is in particular interesting, because during this time the consumer will consume the instant soup mix, when it is still warm. Smaller bubbles are advantageous as compared to bigger bubbles, due to its perceived creaminess.

Although the bubble sizes seem to be the same for the two gas release agents containing sucrose fatty acid ester, coating is favourable above dispersion in the matrix. That is because the coating leads to the prevention of the formation of a foam layer on top of the bulk liquid, as the following experiment shows.

Similarly as above, dry mixtures were prepared containing 10 gram of dry soup mix 1 ; 3 gram of gas release agent coated with 5% sucrose fatty acid ester or gas release agent with 5% sucrose fatty acid ester dispersed in the particle matrix (both from example 2); and 0.2 gram of xanthan gum (Keltrol AP-F). These powders were well mixed to prepare homogeneous dry mixtures. Immediately thereafter 150 ml. of hot water (just after boiling) was added to the mixture and manually stirred for 30 seconds. The height of a possible foam layer on top of the liquid was determined at various times. The results are given in the following table.

Table 10 Gas retained in milliliter on top of mushroom soup containing coated (5% sucrose fatty acid ester) or 5% sucrose fatty acid ester dispersed in particle matrix.

Dispersed 5% Coated 5%

time [min]

Gas retained [mL] Gas retained [mL]

1 55 24

10 47 20

20 40 18

30 32 1 1 The sample with the coated gas release agent did not have any foam on top of the liquid, all gas was retained in the bulk of the liquid. The sample containing gas release agent with dispersed sucrose fatty acid ester had a foam layer on top of the liquid, of about 2 milliliter (5 minutes after addition of water). The gas bubbles were also relatively large, compared to the sample with coated gas release agent. This is illustrated in Figure 3, showing pictures of the two samples described here, taken from the top, 30 minutes after preparation of the two samples. Image A (top) shows the presence of relatively large gas bubbles in a foam layer, on top of the mushroom soup containing gas release agent particles with 5% sucrose fatty acid ester dispersed in the particle matrix. Image B (bottom) does not show a foamy layer, and no relatively large bubbles, in the mushroom soup containing gas release agent particles coated with 5% sucrose fatty acid ester. Example 7: Influence of coating layer on gas release agent on foam layer in beverage

This example shows a hot instant aerated drink, in this case a Cafe Latte type of drink. Dry powder mixtures were prepared containing 2 gram of instant coffee, either 2 gram of uncoated gas release agent (comparative example) or 2 gram of gas coated gas release agent powder (10% palm oil) of example 1 , 0.3 gram xanthan gum (Keltrol AP- F) and 6 gram of a creamer Vana-Cappa 25C (ex FrieslandCampina Kievit,

Netherlands). The mixtures were put in a beaker (250 ml. glass with a diameter of 60 mm). Then 150 ml. water at 85°C was added and stirred for 30 seconds. The beverages had an overrun of around 18%. For both samples, no clear layer of foam could be detected about 5 minutes after preparation, although for the sample with uncoated gas release agent some diffuse layering was visible. For the sample with coated gas release agent, no layering was observed after about 5 minutes. After 15 min this observation was enforced: the sample with uncoated gas release agent had a 30 mm thick foam layer on top, whereas for the sample according to the invention still no foam layer could be seen.

Example 8: Preparation of aerated milk tea Lipton 5 Bean Milk Tea (ex Unilever China, Shanghai, China) instant milk tea powder was used to prepare milk tea. The dry powder is individually packed in sachets, each containing in total 21 .7g of tea extract and milk powder. The amount of milk protein in a prepared milk tea in a cup is more than 0.5%, when following the instructions on pack.

A sachet was taken and added to an empty cup; this was mixed with 0.3g xanthan gum Keltrol AP-F, and 2.0g of gas release agent coated with 10% palm oil (from example 1 ). 150g of water just after boiling was added, and the preparations were manually stirred. This resulted in gas bubbles dispersed in the continuous aqueous phase. No foam layer on the top formed, and the total volume of the aerated milk tea decreased only very slowly during a period of 30 minutes. The following average bubble sizes were determined as function of time.

Table 11 Average bubble size (d3,2) of gas bubbles in milk tea containing coated gas release agent (10% palm oil).

Example 9: Preparation of aerated soy beverage

An aerated soy drink was prepared, by blending 2.0g of gas release agent coated with 10% palm oil (from example 1 ), 0.3g xanthan gum Keltrol AP-F, and 14.0g of a spray dried soy milk. This aerated soy beverage was prepared as a proof of principle.

Therefore the spray dried soy milk drink that was used, had the same composition and the same spray drying process was applied as described in O. Syll et al. (Dairy Sci. & Technol. (2013) 93:431-442). Soy supreme fiber reduced with 45% w/w total protein (ex SunOpta Grains and Food Group, St. Hope, MN, USA) was used to prepare the soy milk to be spray dried. This soy powder was combined with maltodextrin (dextrose equivalent 17, ex Glucidex Roquette, France). The soy protein amount in this mixture was 30% of the total amount of solids. The soy milk was prepared by dissolving the mixture of soy powder and maltodextrin. The total solids concentration in the soy milk was 20 wt%. After spray drying, the dry soy powder-maltodextrin mixture was used to blend with the gas release agent and the xanthan gum.

150g water at ambient temperature was added to this dry mixture, and the preparation was manually stirred. This resulted in gas bubbles dispersed in the continuous aqueous phase. No foam layer on the top formed, and the total volume of the aerated soy drink decreased only very slowly during a period of 30 minutes. The following average bubble sizes were determined as function of time.

Table 12 Average bubble size (d3,2) of gas bubbles in soy beverage containing coated gas release agent ( 10% palm oil).

Example 10: Qualitative determination of yield stress under dynamic conditions

In this experiment model solutions have been prepared containing the relevant hydrocolloid (either 0.2 g, 0.4 g, or 4 g), together with icing sugar (sucrose, 5.0 gram) and erythritol (2.0 g) to prevent lumping of the dry hydrocolloid. The premix was dry mixed well, and subsequently put into a tall form 300 ml glass beaker.

Three different types of precision plastic spheres (The Precision Plastic Ball Company Ltd., UK) are added to the premix in the beaker. These spheres are:

• high density polyethylene (HDPE) spheres, diameter of 3.17 mm coloured green, density of 0.952 g-cm ^"3 ,

• high density polyethylene (HDPE) spheres, diameter of 5.69 mm coloured bright red, density of 0.952 g-cm ^"3 ,

• polystyrene (PS) sphere, diameter of 4.76 mm, coloured dark red, density

1 .04 g-cm ^"3 . The size and density of the spheres was chosen in such a way that they would behave like gas bubbles of approximately 0.1 mm (4.76 mm PS sphere), 0.2 mm (3.17 mm HDPE sphere), and 0.3 mm (5.69 mm HDPE sphere). The differences to bubbles are that the terminal velocity of the probe spheres will be an order of magnitude bigger in a Newtonian fluid and that the PS sphere is going to sediment instead of cream.

For the experiments with xanthan gums, 150 g of water at ambient temperature was poured on top of a dry premix and was vigorously manually stirred with a metal spoon for 30 seconds. The density of the final solutions was (1.014 ± 0.001 ) g-crn ^"3 at 20°C. Xanthan gum's behaviour is independent of the water temperature.

The condition for static bubbles in a liquid which possesses an (apparent) yield stress is (N. D Physics of Fluids 16(12), p. 4319-4330): Where τ (in Pa) is the apparent yield stress, pi is the density of the liquid, p _g is the density of the gas, g = 9.816 m.s ^"2 , and D _b is the bubble diameter. The yield stress is the force required to keep a bubble with volume Ι/β-π-D _t , ³ stationary in the liquid, counteracting the buoyancy. The buoyancy is determined by the density difference between the liquid and the gas, the gravity constant and the surface area of the largest cross-section of the bubble ¼-π- D _b ² . This equation can be written for these spheres as:

Where p _pp is the density of the probe particle, and D _pp is the probe particle diameter. In the following table the critical yield stress for the three probe particles used in these dynamic yield stress measurements is given together with the equivalent bubble diameter in the respective model solutions, calculated with densities at 20°C. The probed yield stress depends on the particle size, particle density and the density of the model solution. With the three probe particles we cover more or less the range of apparent yield stress that would immobilize bubbles with diameters ranging from about 100 to 400 micrometer. Table 13 Critical yield stress for the three probe particles, together with the equivalent bubble diameter in the respective model solutions.

For the experiments with modified starches, 150 g of hot water (just after boiling) was poured on top of the premix and is vigorously stirred by hand with a metal spoon for 30 seconds. Here hot water is used, in order to gelatinise the starch and make it functional. The density of the final solutions was (1.023 ± 0.001 ) g-cm ^"3 at 20°C. After the stirring the spheres were suspended at a certain height in the liquid, and depending of the yield stress generated by the hydrocolloid, they would slowly move upward, or downward, or they would remain at its place. The higher the yield stress, the slower the spheres would move. The beaker was positioned on a stand and pictures were taken at fixed time intervals for 5 minutes. This way the movement of the spheres could be followed in time. The translation of the spheres relative to its starting position can be plotted as function of time in a graph. In case the processes are too fast to be captured on pictures, a video record was made instead.

If there is no yield stress in the system, the spheres will move with a constant velocity through the liquid. If sufficient yield stress is developed by the time the picture taking will have commenced the spheres will stay motionless. If yield stress is developing during the time of the experiments, the spheres' motion is going to be decelerative, i.e. they will slow down and eventually stop moving. The trajectories of the spheres in the experiments described above are measure using video imaging software ImageJ. As a result we get the translation of each type of sphere with time in the studied system. The following experiments were performed. Table 14 Description of experiments with precision spheres.

^* corrected for the icing sugar and erythritol The movement of the spheres in each experiment has been plotted in various graphs in Figure 4 and Figure 5. In some cases duplicate measurements are shown, wherein two similar spheres are followed. In general reproducibility is very good, as the trajectories of these two spheres almost coincide.

• In experiment 10-1 the largest sphere translates the most from its initial position, as compared to the other spheres. The smaller spheres only have a small translation.

• In experiment 10-2 the concentration of hydrocolloid has doubled, and the spheres nearly do not move. The maximum measured translation is about 0.25 cm. This shows that the yield stress in this system is high enough to suspend the spheres.

• In experiment 10-3 the yield stress did not develop rapidly enough to keep the largest sphere suspended, this sphere floated to the surface. The smaller spheres initially show a relatively rapid movement, which then decelerates because of the development of sufficient yield stress to keep the small spheres suspended.

• In experiment 10-4 the translation was very small, like in experiment 10-2. The yield stress that develops This shows that the yield stress in this system is high enough to suspend the spheres.

• In experiment 10-5 the behaviour of the spheres is different than in the previous experiments. The HDPE spheres rapidly moved to the surface of the liquid, and the PS sphere sedimented within 2 seconds. This is shown in Figure 5, where the translation of the particle lies on a straight line with a constant slope. This is indicative of typical Newtonian fluid rheology. Keltrol RD does not have any effect on dissolution or yield stress development.

• In experiment 10-6 the spheres show similar behaviour as in experiment 10-5, although the time scale is different, the HDPE particles initially accelerate, and after that move with constant velocities until they surface. This is a typical behaviour of probe particles in Newtonian fluid, and this shows that the presence of Keltrol RD in the solution does not lead to the development of yield stress large enough to oppose the buoyancy force acting on the HDPE particles. The PS particles show different behaviour: they initially decelerate and then move at constant velocities. The initial deceleration might be due to the nature of the experiment. In this case the PS particle were thrown into the solution after the video recording had started, i.e. they had some initial non zero velocity when they contacted the solution. Therefore, they decelerated due to the viscous drag of the solution. After the initial period of time all three PS particles moved with the same constant velocity during the time of the measurement, showing the same Newtonian behaviour of the surrounding solution.

• In experiment 10-7 the HDPE spheres rapidly moved to the surface of the liquid, while the PS spheres only showed limited movement, as shown in Figure 6 (duplicate measurement). The yield stress was sufficient to suspend the PS spheres.

· Also in experiment 10-8 similar behaviour of the spheres was observed. The HDPE spheres rapidly moved to the surface, while the PS spheres remained suspended during the experiment, see Figure 6 (duplicate measurement).

Therefore the amount of modified starch used to keep spheres suspended in the continuous liquid phase, is much higher concentration than the xanthan gums Keltrol AP and Keltrol AP-F. The amounts of Keltrol AP or Keltrol AP-F are 10 to 20 times lower than the amounts of modified starches to obtain the same effect.