TECHNICAL FIELD

The invention relates in general to a dairy composition suitable for making a foamed dairy product, to its manufacture process, and to a process for preparing a foamed dairy product.

BACKGROUND OF THE INVENTION

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Yoghurt is a common dairy product consumed globally. Its organoleptic properties have a large effect on consumer acceptability. Whipped yoghurts (also called yoghurt mousses) evolved as a new category of dairy products due to their ability to provide new and unique textures, mouth-feels and product appearances.

Currently, the large majority of texturized chilled products that are consumed at home, such as whipped yoghurt, are bought chilled or frozen at the selling point, and are consumed at home without the need of any additional preparation. However, these products have several drawbacks. Among others, the cold chain must remain unbroken for such products, from the manufacturing point to the transporters, retailers, through to the consumer's refrigerator. Transport at chilled temperature is costly, and temperature fluctuations during transport, loading and unloading impact the product quality. At the selling point and at home, the products must be stored in a refrigerator, which imposes limits on the diversity of the product offering, considering the standard refrigerator volume.

Whipping or foaming consists in dispersing and stabilizing a gas phase (usually nitrogen or air) in the form of tiny bubbles into the continuous yoghurt matrix. Foaming processes can be performed batchwise or continuously. For instance, foaming may be performed by batch with standard kitchen mixers, such as a HOBART or a KITCHENAID mixer. Continuous foaming is generally performed on an industrial scale, for instance using equipment described in WO 2013/068426 Al. The properties of the foamed yoghurt depend on the foaming operation, gas fraction (expressed as the overrun), the bubble size distribution, as well as on the distribution of the ingredients between the bulk and the gas-yoghurt interface. Usually, the manufacture of commercial yoghurt mousses is based on a continuous process. The foams are characterized by on overrun of about 100% which remains stable for 1 month under refrigerated storage conditions.

Patent application WO 2010/122033 A2 discloses fermented dairy products with reduced caloric values, in particular low-fat milkshakes and smoothies having reduced amounts in sugar. The dairy product contains gelatine. It also contains live probiotic bacteria. The compositions which contain an emulsifier exhibit a foaming rate of less than 50%, lower than the compositions which do not contain the emulsifier. The compositions which contain gelatine having a bloom index of 125 or 130, without emulsifier, exhibit a foaming rate above 50% or 70%. Patent application WO 2010/122376 Al relates to a similar product. This document also discloses a composition which contains alive probiotics.

Patent application WO 2011/084570 Al discloses a whippable composition suitable for making a topping. The composition comprises yogurt and a whip topping emulsion. The yoghurt and the whip topping emulsion are prepared separately, and then combined at low temperature (3 to 15°C). The composition is manufactured in a manner that preserves the microflora of the yogurt. It has a shelf life of up to one year when frozen. The whippable composition must be thawed for at least 12 hours in a refrigerator (4 to 7°C) before whipping in a mixer. The finished whipped product may be stored for up to 5 days in a refrigerator.

Patent application US 2003/068406 Al discloses a chilled whipped yogurt product and its method of preparation. In particular, a hydrated pasteurized emulsifier blend is added after fermentation of the yogurt product, before aeration. The hydrated emulsifier blend contains a wetting agent such as polysorbates or sodium stearyl lactylate, and an emulsifier blend of lactylated mono- and di-glycerides. The yogurt product also contains gelatine. A gas in injected into the product, and then it is whipped with a standard continuous whipping equipment. The whipped product is stored, distributed and sold under refrigerated conditions.

Patent application US 2011/020512 Al discloses a method to enhance the foam retention property of a beverage. Enhanced foam retention properties in a beverage are achieved with a fermentation-derived cellulose complexed with a high-molecular substance such as xanthan gum, guar gum, and carboxymethylcellulose.

JP 2007 006738 A discloses a method for producing a fermented milk beverage having a good storage stability.

Whey ingredients are known ingredients in the dairy industry. They can provide nutritional and functional benefits to yogurts and yogurt beverages ("U.S. Whey Ingredients in Yogurt and Yogurt Beverages, Alan Hugunin, U.S. Dairy Export Council, 2009).

Patent application US 2012/0052160 Al discloses a foamable composition that comprises calcium-depleted casein and whey protein. This composition has foaming and heat-set characteristics similar to that of egg white.

Patent US 5,308,628 relates to a method of preparing frozen dairy desserts. Specifically, a method of preparing thickener-free ice cream from a mixture of fermented milk constituents and sugars, is disclosed.

As outlined above, foaming agents, stabilisers, and gelling agents are used in industrial processes. In general the foaming agents are emulsifiers such as mono- and di-glycerides and their derivatives, which are not always well perceived by consumers. Gelatine is a common stabilizer in commercial products. Gelatine is produced by partial hydrolysis of collagen extracted from animal tissues, such as cattle or pig. Gelatine replacement represents a major consumer requirement in the recent years, as well as for the vegetarian, halal and kosher markets. Similarly, hydrocolloids such as xanthan gum, guar gum, or cellulose derivatives are not always well perceived by consumers.

It is desirable to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. Especially, it is desirable to provide a foamed dairy product comparable to a foamed yogurt, without gelatine or other food additives generally used to stabilise foamed yogurt. It is also desirable that such product be prepared and exhibit consistent organoleptic characteristics upon consumption by the consumer, despite the absence of undesired foaming or gelling agents. SUMMARY OF THE INVENTION

To this end, a first embodiment of the invention proposes a liquid dairy composition suitable for making a foamed dairy product, wherein said liquid dairy composition is shelf-stable under ambient storage conditions, has a pH between 3.8 and 4.6, and comprises fermented milk, up to 3% by weight of whey protein concentrate based on the weight of the total composition, up to 6% by weight of fat based on the weight of the total composition, optionally up to 1% by weight of high methylester pectin based on the weight of the total composition, optionally up to 4% by weight of starch based on the weight of the total composition; and wherein the liquid dairy composition has a whey protein / casein ratio ranging from 0.8 to 3 and a dairy protein content ranging from 4.5 to 5.5% by weight based on the weight of the total composition.

In an embodiment, the foamed dairy product is a foamed yogurt-type product or a foamed yogurt.

Preferably, the liquid dairy composition is a foamable liquid dairy composition. It is suitable for making a foamed dairy product having an overrun of 50% to 150%.

In an embodiment, the liquid dairy composition comprises from 0.05% up to 5% by weight of fat based on the weight of the total composition.

In an embodiment, the liquid dairy composition comprises from 1.2 to 2.5% by weight of whey protein concentrate based on the weight of the total composition.

In an embodiment, the liquid dairy composition has a total solid content from

10 to 30% based on the weight of the total composition, preferably from 13 to 30%.

In an embodiment, the liquid dairy composition comprises from 60% to 97% by weight of fermented milk based on the weight of the total composition.

In an embodiment, the liquid dairy composition is packed in a single-portion container. Such compositions may be used in the preparation of a foamed dairy product, for instance a foamed yogurt-type product, in less than 5 minutes, starting from the liquid composition at an ambient temperature.

It was quite surprising for the inventors to achieve the preparation of a cooled, single portion of a foamed yogurt-type product, with such a high overrun, a pleasant mouthfeel, while starting from a non-foamed low-fat acid fermented dairy composition, all in less than 5 minutes.

A second embodiment of the invention proposes a pack comprising at least two containers, preferably single-portion containers, wherein at least one of said containers contains a liquid dairy composition according to the first embodiment of the invention, and wherein each of the remaining containers contains a liquid composition selected from the group comprising: a liquid dairy composition according to the first embodiment of the invention, a liquid composition which is shelf-stable under ambient storage conditions and is suitable for making a frozen confection, and a liquid composition which is shelf-stable under ambient storage conditions and is suitable for making a chilled beverage containing a dairy component and a sweet flavour component.

A third embodiment of the invention proposes a process of manufacturing a liquid dairy composition suitable for making a foamed dairy product, comprising the steps of:

a) providing a liquid milk blend,

b) homogenising and pasteurising the milk blend,

c) inoculating the milk blend with ferment, and fermenting said milk blend until it reaches a pH between 3.8 and 4.6, to obtain a fermented milk composition,

d) before step f), adding up to 1% by weight of high methylester pectin based on the weight of the total composition, to the milk blend or to the fermented milk composition,

e) before step f), adding up to 4% by weight of starch based on the weight of the total composition, to the milk blend or to the fermented milk composition, f) homogenising and heat-treating the fermented milk composition, to obtain said liquid dairy composition which is shelf-stable under ambient storage conditions, g) packing said liquid dairy composition,

wherein up to 3% by weight of whey protein concentrate based on the weight of the total composition is added to the liquid milk blend, to the fermented milk composition, or to the heat-treated fermented milk composition,

and wherein the liquid dairy composition has a whey protein / casein ratio ranging from 0.8 to 3, has a dairy protein content ranging from 4.5 to 5.5% by weight based on the weight of the total composition, and comprises up to 6% by weight of fat based on the weight of the total composition.

In an embodiment, the whey protein concentrate is added to the liquid milk blend.

In an embodiment, the high methylester pectin or the starch is added to the fermented milk composition before homogenising and heat-treating the fermented milk composition. Preferably, the high methylester pectin and the starch are both added to the fermented milk composition before homogenising and heat-treating the fermented milk composition.

In an embodiment, the liquid dairy composition is packed into a single-portion container. Preferably, the liquid dairy composition is packed aseptically.

A fourth embodiment of the invention proposes a process of preparing a foamed dairy product, comprising the steps of

a) providing a liquid dairy composition according to the first embodiment of the invention, at ambient temperature, preferably at a temperature between 10°C and 25°C

b) cooling the liquid dairy composition to a temperature between 1°C and 8°C for a period below 10 minutes, preferably below 5 minutes, even more preferably below 3 minutes, under mild agitation, and then,

c) aerating the liquid dairy composition to an overrun in the range from 50% to 150% by stirring the composition with a stirring member. In an embodiment, the foamed dairy product is a foamed yogurt-type product or a foamed yogurt.

In an embodiment, the liquid dairy composition is dispensed from a single- portion container into a process container before step b).

In an embodiment, said stirring member has a planetary movement with an angular velocity ω2 between 100 and 200 rpm and a rotation about an axis with an angular velocity ωΐ of 0 to 350 rpm during the cooling step b).

In an embodiment, the aeration step c) lasts up to 120 seconds, preferably from 60 to 90 seconds. Preferably, the liquid dairy composition is further cooled down to or maintained at a temperature between 1°C and 5°C during the aeration step c).

In an embodiment, said stirring member has a planetary movement with an angular velocity ω2 between 200 and 400 rpm and a rotation about an axis with an angular velocity ωΐ of 500 to 1200 rpm during the aeration step c).

In an embodiment, the angular velocity ωΐ has an opposite direction to the angular velocity ω2 during the cooling step, during the aerating step or during both the cooling and aerating steps. Preferably, the angular velocity ωΐ has an opposite direction to the angular velocity ω2 at least during the aerating step.

These and other aspects, features and advantages of the invention will become more apparent to those skilled in the art from the detailed description of embodiments of the invention, in connection with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures are provided as black-and-white pdf documents after conversion from a coloured pre-conversion document. The pre-conversion document is filed together with this patent application as the "pre-conversion archive".

Figure 1 is a diagram showing embodiments of the process of manufacturing a liquid dairy composition.

Figure 2 shows air bubbles dispersions using a quantitative image analysis, from foamed compositions Rl of Example 1. Figure 3 is a confocal microscopy picture showing simultaneously the distribution of fat (in red in the pre-conversion figure) and proteins (in green in the pre- conversion figure), in the liquid dairy composition recipes Rl of Example 1 before whipping.

Figure 4 are confocal microscopy pictures showing simultaneously the distribution of fat (in red in the pre-conversion figure) and proteins (in green in the pre- conversion figure), in foamed recipes Rl and RC4 of Example 1.

Figure 5 are confocal microscopy pictures showing the distribution of fat (in red in the pre-conversion figure) at the air bubbles interface, in foamed recipes Rl and RC4 of Example 1.

DETAILED DESCRIPTION OF THE INVENTION

Unless the context clearly requires otherwise, throughout the specification, the words "comprise", "comprising" and the like are to be construed in an inclusive sense, that is to say, in the sense of "including, but not limited to", as opposed to an exclusive or exhaustive sense.

As used in the specification, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

Unless noted otherwise, all percentages in the specification refer to weight percent, where applicable.

Unless defined otherwise, all technical and scientific terms have and should be given the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

In a first embodiment, the invention relates to a liquid dairy composition suitable for making a foamed dairy product. The liquid dairy composition is shelf-stable under ambient storage conditions. In the context of the invention, "ambient" refers to an ambient temperature, for instance between 15°C and 25°C. More specifically, in the context of the invention, "shelf-stable under ambient storage conditions" means that the composition does not undergo spoilage, and maintains its organoleptic properties, in particular its foaming capacity, for up to 6 months, preferably up to 9 months, when stored at a temperature of up to 20°C, and preferably up to 25°C. In a preferred meaning, the liquid dairy composition is shelf stable for up to 9 months at 25°C. To achieve the desired shelf life, the liquid dairy composition is heat-treated. For instance, the liquid dairy composition is heat-treated at a temperature lower than 100°C as it has a pH lower than 4.6. The pasteurisation temperature could range from 75°C to 95°C for 2 to 180 sec depending on the composition. Thus, the ferments in the liquid dairy composition are inactivated.

In this context, the invention relates in part to a liquid dairy composition which is shelf-stable at storage temperatures ranging from 15°C to 25°C, for up to 6 months, and even up to 9 months. In particular, the liquid dairy composition comprises fermented milk, where ferments are inactivated. Preferably, inactivation of the ferments is performed by heat treatment, such as pasteurisation.

During storage, the liquid dairy composition is non-foamed. Nevertheless, the liquid dairy composition remains foamable upon appropriate aeration, as will be explained below.

The liquid dairy composition has a pH between 3.8 and 4.6, preferably between 4.1 and 4.3, and more preferably about 4.2. The pH of the composition results from fermentation of milk by a starter culture, during manufacture of the composition, as will be explained below and is illustrated on Figure 1. An acidic pH is a usual component in the flavour of a yogurt-type product.

In an embodiment, the liquid dairy composition comprises, or is, a liquid fermented dairy composition, such as a liquid yogurt-type composition. Preferably, the liquid dairy composition comprises, or is, a heat-treated liquid fermented dairy composition, where the heat-treatment is sufficient to inactivate the ferments therein. Within the context of the present invention, "liquid" refers to a composition having a viscosity which may range from 30 000 to 100 000 mPa.s.

Usually, foamed dairy products must be stored under chilled conditions, and they contain foaming agents, stabilisers, and gelling agents, all of which do not derive from milk. The liquid dairy composition does not contain gelatine. The liquid dairy composition does not contain foaming agents that do not derive from milk. The liquid dairy composition is non-foamed. The liquid dairy composition is shelf-stable under ambient storage conditions, and it can be used to prepare a foamed dairy product, preferably a yogurt-type foamed product, in less than 5 minutes. This is quite an exceptional achievement.

The liquid dairy composition contains fermented milk. While bovine milk is preferred, other milks can be used instead of, or in addition to bovine milk. Examples of alternative milk include camel, goat, sheep and equine milk. Alternatively, milk can comprise vegetable milk, such as soy milk. Various milk ingredients can be used, including skim milk, semi-skim milk, full-fat milk, in a liquid or powder form, condensed milk, as well as milk fractions. Preferably, milk is inoculated with standard yogurt ferments, namely Lactobacillus bulgaricus and Streptococcus thermophilus. Most jurisdictions provide a regulatory definition of "yogurt", depending on the presence of live or inactivated yogurt ferments, on the presence or absence of other ferments, or on their respective ratios. However, the invention should not be limited by such regulatory definitions. Indeed, milk can also be inoculated with and fermented by other ferments, such as bacteria from a genus selected from Lactobacillus, Leuconostoc, Streptococcus, Lactococcus, Bifidobacterium, Enterococcus, and Pediococcus. For instance, the ferment may be selected from Lactobacillus acidophilus, L. plantarum, L. casei, L. lactis, L. helveticus, L. paracasei, L. cremoris, L. rhamnosus, L. delbrueckii, L. reuteri, L. johnsonii, L. brevis, Streptococcus thermophilus, Lactococcus lactis, Bifidobacterium longum, B. breve, B. bifidum, B. infantis, and B. lactis. The liquid dairy composition comprises from 60% to 97% by weight of fermented milk based on the weight of the total composition, preferably from 75% to 97% by weight of fermented milk based on the weight of the total composition. Preferably, the fermented milk is prepared from bovine milk.

In addition to fermented milk, the liquid dairy composition comprises up to 3% by weight of whey protein concentrate based on the weight of the total composition. In an embodiment, the liquid dairy composition comprises at least 1.2% by weight of whey protein concentrate based on the weight of the total composition. Preferably, the liquid dairy composition comprises from 1.2% up to 3% by weight of whey protein concentrate based on the weight of the total composition, more preferably from 1.5% up to 2.8%, and even more preferably from 1.8% up to 2.5% by weight of whey protein concentrate based on the weight of the total composition. Whey protein concentrates are used to increase the foaming capacity of the liquid dairy composition. In addition, whey protein concentrates have a better taste profile than whey protein hydrolysates. However, adding more than 3% by weight of WPC may lead to flocculation issues during the heat-treatment, as will be explained later. Too much WPC may also impact the flavour profile of the final product. Whey protein concentrate can be found from various suppliers. For instance, WPC can be obtained from Fonterra, such as WPC515. Whey proteins are natural components of milk. Hence, in the liquid dairy composition, whey proteins may come from the fermented milk, and from whey protein concentrate. Unless indicated otherwise, "whey protein content" includes whey protein from the fermented milk and whey protein from the whey protein concentrate.

Preferably, the whey protein / casein ratio in the liquid dairy composition ranges from 0.8 to 3. When the whey protein / casein ratio is below 0.8, it becomes difficult to reach the desired overrun in a short timeframe. On the other hand, when the whey protein / casein ratio is above about 3, the milk blend may become unstable during the pasteurisation (before the fermentation step) and there is a higher risk of floculation of the proteins. Preferably, the whey protein / casein ratio ranges from 0.8 to 2, more preferably from 0.9 to 1.5.

As mentioned above, the liquid dairy composition comprises from 4.5 to 5.5% by weight of dairy protein based on the weight of the total composition.

As mentioned above, the liquid dairy composition is heat-treated. For instance it is pasteurised. An objective of the heat-treatment is to inactivate the ferments in the fermented milk composition. Appropriate heat-treatments are known to the person of ordinary skill in the art. Proteins, in particular whey proteins, must be protected against the heat-treatment, so that they retain their foaming properties after heat-treatment. This is achieved by the addition of high methylester (HM) pectin based during manufacture of the liquid dairy composition. HM pectin have a degree of methyl esterification (DE) higher than 50. Hence, the liquid dairy composition comprises up to 1% by weight of high methylester pectin based on the weight of the total connposition. Examples of HM pectin include Pectin Genu Type HM-115-H from CP Kelco, Grindsted Pectin AMD Series from Dupont Dansico. Alternatively to HM pectin, carboxymethylcellulose (CMC) can be used. Examples of CMC include Cekol HVD from CP Kelco, Grindsted AMD 258 from Dupont Danisco, Walocle CRT 1000 from Dow.

The liquid dairy composition also contains up to up to 5% by weight of fat based on the weight of the total composition. Preferably, the liquid dairy composition contains less than 4%, or less than 3%, or less than 2% by weight of fat based on the weight of the total composition. Usually, mouthfeel and foam structure are achieved thanks to a relatively high fat content, for instance above 6% by weight, especially in fermented milk products. Indeed, the low pH of such products is detrimental to foaming, and this is counterbalanced by the high fat content or the presence of gelatine. The liquid dairy composition has a low fat content, even as low as 0.05% of fat based on the weight of the total composition. Despite this low fat profile, the liquid dairy composition can be used in the preparation of a foamed dairy product, such as a foamed yogurt-type product, with an appealing mouthfeel and a rather high overrun of 50% to 150%. For instance, the liquid dairy composition comprises from 0.05% up to 2% by weight of fat based on the weight of the total composition. Preferably, the liquid dairy composition comprises from 0.1% up to 1.5% by weight of fat based on the weight of the total composition.

Preferably, the fat is milk fat, although vegetable fat could also be considered, especially to improve the fat profile of the liquid dairy composition, from a nutritional perspective. For instance, the content in mono-or poly-unsaturated triglycerides could be adjusted to provide a better balanced fat profile. Milk fat can be added from various ingredients, such as cream, or whole milk. Non-milk fat can be added from various vegetable oils, such as coconut oil, palm oil, sunflower, rapeseed oil. Mixes of milk fat ingredients and vegetable oils are also useful.

The liquid dairy composition can further include sweeteners, such as nutritive carbohydrate sweetening agents. Examples of nutritive carbohydrate sweetening agents include sucrose, high fructose corn syrup, various DE corn syrups, beet sugar, cane sugar, malt extract, honey, or maple syrup.

The liquid dairy composition can contain further ingredients such as minerals and vitamins, flavours and aromas, such as fruit extract, fruit juice, fruit syrup, fruit puree, fruit flavour, cereal ingredients, cereal flavour, vanilla, chocolate, coffee, or caramel. Examples of fruit components include for instance, but are not limited to apricot, banana, strawberry, maracuja, grape, grapefruit, or mango. For instance, the liquid dairy composition may contain up to 30% by weight of a fruit component, preferably a fruit preparation which contains fruit syrup, fruit zest and/or fruit puree. For example, the liquid dairy composition contains about 20% of a fruit component.

Preferably, the liquid dairy composition is essentially or completely free of any artificial or non-natural emulsifier or stabilizer. Examples of artificial and non-natural ingredients which are avoided in a particular embodiment of the invention include for example the following emulsifiers: mono- and diglyceride of fatty acids, acid esters of mono- and diglycerides of fatty acids such as acetic, lactic, citric, tartaric, mono- and diacetyl tartaric acid esters of mono- and diglycerides of fatty acids, mixed acetic and tartaric acid esters of mono- and diglycerides of fatty acid, sucrose esters of fatty acids, polyglycerol esters if fatty acids, polyglycerol polyricinoleate, polyethylene sorbitan mono-oleate, polysorbate 80 and, chemically extracted lecithins.

Chemically modified starches which are used in the art as stabilizers are also preferably avoided. These include for example modified starch, monostarch phosphate, distarch phosphate, phosphate or acetylated distarch phosphate, acetylated starch, acetylated distarch adipate, hydroxyl propyl starch, hydroxypropyl distarch phosphate, acetylated modified starch. Hydrocolloids such as xanthan gum, guar gum, carboxymethylcellulose or other cellulose derivatives, are also preferably avoided. Usually, these hydrocolloids are used in the art as texture agents. The products of the present invention are preferably essentially free of the preceding synthetic esters, modified starches, and hydrocolloids.

In the context of the invention, "essentially free" means that these material are not intentionally added for their conventional property imparting abilities, e.g. stabilizing, although there could be unintended nninor amounts present without detracting from the performance of the products. Generally and preferably, the products of the invention will not contain any non-natural materials. By the term "essentially or completely free" is therefore meant that the product comprise 1% by weight or less of a given compound.

For instance, the liquid dairy composition is essentially free of xanthan gum, or guar gum, or carboxymethylcellulose, or other cellulose derivatives, or synthetic esters, or modified starches, or their mixtures.

However, the liquid dairy composition may comprise starches which are not chemically modified, such as native starch or physically-modified starch. Optionally up to 4% by weight of starch based on the weight of the total composition. Examples of native starch include, for instance, rice starch, maize starch, or potato starch. Native starch are staple ingredients in the food industry. Suitable examples of physically- modified starches include, for instance, C Tex 06204 from Cargill or Clearam CH 4020 from Roquette.

The liquid dairy composition has a total solid content from 10 to 30% based on the weight of the total composition. Too high a total solid content may impact negatively the viscosity and foamability of the liquid dairy composition.

The liquid dairy composition may be packed in a container, preferably a single- portion container. Preferably, packing of the liquid dairy composition is done aseptically, to avoid any contamination with environmental bacteria, spores, or moulds, and prevent spoilage during storage. The single-portion container can be used, as will be explained below, in the preparation of a foamed dairy product. In the context of the invention, "single-portion container" encompasses any container suitable for being disposed after being used for the preparation of the single-portion of foamed dairy product. Thereby, the containers are preferably at least partially recyclable. "Single-portion" also means that the container contains the amount of liquid dairy composition sufficient to prepare one portion of foamed dairy product. For instance, one portion of foamed dairy product represents any amount of product from 50g to 180g, such as 50g, 60g, 70g, 80g, 90g, lOOg, HOg, 120g, 130, 140g, 150g, 160g, 170g, or 180g of product. Alternatively, one portion can represent any volume between 50mL and 150mL of liquid dairy composition, such as 60mL, 70mL, 80mL, 90mL, lOOmL, HOmL, 120mL, 130, 140mL, or 150mL of liquid dairy composition.

Further, the container may also be designed for being used as process container, i.e. a container in which the foamed dairy product is prepared, as well as serving container, i.e. a container from which the consumer may directly consume the resulting foamed dairy product. Preferably, the packaging container comprises an identification means containing a recipe code related to the type of foamed dairy product to be prepared. In a preferred mode, the identification means comprises at least one barcode. In an embodiment, the container is a pouch from which the liquid dairy composition may be dispensed into a separate process container.

As will be described below, the liquid dairy composition can be used in the preparation of a foamed dairy product, such as a foamed yogurt-type product. Preparation of the foamed dairy product can be executed in less than 5 minutes, preferably in about 3 minutes. As the liquid dairy composition is shelf-stable under ambient storage conditions, it does not need to be stored at refrigerated temperatures, contrary to current foamed or whipped dairy products. For instance, it may be stored at ambient temperatures in warehouses or in shops. In addition, the foamed dairy product can be prepared easily and directly from an ambient temperature liquid composition, as a single portion, which reduces losses which typically occur in standard whipping devices. The foamed product has a low fat content, which is very interesting from a nutritional standpoint. Possibly, the foamed product does not contain gelatine. Because whipping can be performed at the moment of consumption, instead of several days or weeks before with standard whipped yogurts, it becomes possible to overcome issues associated with transport, the cold chain or the fragile structure of whipped products. For instance, the product does not show structure/texture changes, or syneresis. In fact, it becomes possible to offer a foamed dairy product, with consistent and high quality, to be prepared at home for instance. Therefore, in an embodiment, the invention relates to a pack comprising at least two containers, preferably single-portion containers, wherein at least one of said containers contains a liquid dairy composition as described above. The remaining containers contain a liquid composition selected from: a similar liquid dairy composition, a liquid composition which is shelf-stable under ambient storage conditions and is suitable for making a frozen confection, and a liquid composition which is shelf-stable under ambient storage conditions and is suitable for making a chilled beverage containing a dairy component and a sweet flavour component. In other words, the pack comprises one or several categories of containers, preferably single-portion containers. Said frozen confection could be selected from a smoothie, a frappuccino, a sorbet, or an ice-cream. Examples of liquid compositions suitable for making a frozen confection are described in co-pending International patent applications PCT/EP2015/060000 and PCT/EP2015/060002 filed on May 6, 2015. Said chilled beverage, such as a chilled dairy beverage, could be selected from caffe latte, tea latte, cereal-based dairy beverage, milk-shake type beverages, including milk-shake flavoured with fruit, cocoa, coffee, caramel, vanilla, malt, or tea.

Either all of the containers, or only some of them contain a liquid dairy composition as described above, which are suitable for making a foamed dairy product, such as a foamed yogurt-type product. In that situation, the liquid dairy composition in each container may be flavoured differently from one another, or may all have the same flavour, or may have other combinations of flavours. When only some of the containers contain such a liquid dairy composition, the remaining containers are any combination of containers containing a liquid composition suitable for making a frozen confection, and a liquid composition suitable for making a chilled beverage containing a dairy component and a sweet flavour component. Preferably, the pack comprises only single-portion containers. For instance, the pack comprises only containers which contain a liquid dairy composition suitable for making a foamed dairy product, such as a foamed yogurt-type product. For instance, the pack is for on-shelf disposal. In this event, the pack preferably comprises a single category of containers, for instance from 10 to 50 containers. Alternatively, the pack may be to be bought by consumers. In this event, the pack may comprise a mix of containers, for instance from 2 to 20 containers.

An example of a process of manufacturing the liquid dairy composition will be described with reference to Figure 1. The process for manufacturing the liquid dairy composition begins with preparing or providing a liquid milk blend. Preferred or alternative milk sources, and fat contents are described above. Sweeteners can be added in the liquid milk blend at this stage. Sweeteners can be added in the dry blend, when relevant, or as an aqueous solution into the liquid milk blend. The ingredients are mixed to form a homogeneous liquid blend. The blend can be stored overnight for complete hydration, especially when using milk powder. The milk blend is then heated from the typical milk storage temperature of 4-5°C, to about 70°C prior to homogenization in a conventional homogeniser. Homogenisation further disperses the fat component and other ingredients. To ensure that no biological contamination occurs before fermentation, the milk blend is pasteurised typically at 92°C for 6 minutes. Alternative heat-treatments are known to the person of ordinary skill in the art. Then the homogenised and pasteurised milk blend is cooled to the fermentation temperature. The fermentation temperature depends on the ferment. Typically, it varies between 37°C and 45°C.

A ferment is added to the milk blend, for instance as a freeze-dried culture. The starting conditions (pH, water content, inoculation ratio) as well as the fermentation condition (temperature, duration) are generally known. Fermentation of the milk blend is performed until a pH between 3.8 and 4.6 is reached. Preferably, the target pH is from 4.1 to 4.3, and even more preferably, about 4.2.

Thereafter, the fermented dairy product - "the curd" - is broken, smoothed, and cooled to about 20°C. As explained above, this is where high methylester pectin and/or starch may be added to the composition. When the high methylester pectin and the starch are added after fermentation, these ingredients undergo only one heat- treatment which is beneficial for taste and texture purposes. However, it is worth noting that the starch and/or the high methylester pectin could also be added into the liquid milk blend, prior to pasteurisation and homogenisation. Pectin and starch can be added as an aqueous solution or as a dry blend. A sweetener can be added in the fermented dairy product at this stage also, preferably as an aqueous solution. Preferably, the composition is let to rest for sufficient time, such as 15 to 30 minutes, before a heat treatment is performed to inactivate the ferments. Conventionally, the composition is pre-heated to about 70°C, then it is homogenised, pasteurised typically at 94°C for 3 minutes, then cooled down to about 20°C for final storage in aseptic conditions.

A fruit preparation can be added to the composition during aseptic storage. The fruit preparation must also be aseptically treated. The pasteurised fermented dairy composition is then filled aseptically into a container, preferably a single-portion container, before storage in ambient conditions. Hence, the liquid dairy composition is not foamed before storage. In other words the liquid dairy composition is non-foamed.

As shown on Figure 1, the whey protein concentrate (WPC) may be added at several steps during the manufacture of the liquid dairy composition. Preferably, the whey protein concentrate is added in the liquid milk blend, at the very beginning of the process. Alternatively, or in addition to it, whey protein concentrate can be added during storage, just before the final pasteurisation, for instance together with the pectin ingredient. Finally, but this is less preferred due to the risk of contamination, aseptically treated whey protein concentrate may be added in the aseptic storage. In that case, it is preferred that the whey protein concentrate be added as a blend in liquid milk.

Another embodiment of the invention is a process of preparing a foamed dairy product, comprising the steps of

a) providing a liquid dairy composition as described above, at ambient temperature, preferably at a temperature between 10°C and 25°C,

b) cooling the liquid dairy composition to a temperature between 1°C and 8°C for a period below 10 minutes, preferably below 5 minutes, even more preferably about below 3 minutes, under mild agitation , and then, c) aerating the liquid dairy composition to an overrun in the range from 50% to 150% by stirring the composition with a stirring member.

As can be understood from the brief description of the process above, the liquid dairy composition is non-foamed at the beginning of the process.

Preferably, the foamed dairy product is a foamed yogurt-type product or a foamed yogurt. The foamed dairy product is spoonable. The foamed dairy product is not a frozen product. Preferably, the liquid dairy composition is aerated to an overrun from 70% to 140%, more preferably from 80% to 130%. The overrun is defined in the examples below. The foamed dairy product does not flow easily from the processing container: it must be spooned off for consumption for instance, as a set yogurt or a dessert creme. In addition, the foamed dairy product has a micro-foam structure with very small bubbles distributed throughout the product. For instance, the bubbles have a size between 50 and 110 μηη. This imparts a very light and smooth texture to the foamed dairy product.

In particular, this is achieved with a single-portion whipping and cooling device as described in co-pending application PCT/EP2013/072692 filed on 30 October 2013 and published as WO 2014/067987, or in co-pending application PCT/EP2015/059930 filed on 6 May 2015.

In an embodiment, the foamed dairy product is prepared in its container. In particular, the foamed dairy product is prepared in its container from the non-foamed liquid dairy composition. For this purpose a container is having a heat exchange contact surface through which the liquid dairy composition is cooled may conveniently be used. This allows for a quick cooling of the liquid dairy composition when the container is brought into contact with cooling means during the aeration.

Alternatively, the liquid dairy composition is dispensed from a single-portion container into a process container before step b). ). The liquid dairy composition is a non-foamed liquid dairy composition. The duration of the cooling step depends mainly on the initial temperature of the liquid dairy composition. For instance, the cooling step may last from 5 to 100 seconds. During the cooling step, the stirring member imparts a mild agitation to the liquid dairy composition. The liquid dairy composition is non-foamed before the agitation and aeration steps.

The objective of the mild agitation is to ensure a homogeneous temperature distribution throughout the liquid dairy composition without incorporating air, or with marginal incorporation of air. Indeed, air slows down heat transfers. Once the liquid dairy composition contains air bubbles, it becomes more difficult to cool it down to the target temperature. In addition, the mild agitation prevents freezing of the liquid dairy composition onto the internal walls of the processing container.

For instance, during the cooling step b), the stirring member has a planetary movement with an angular velocity ω2 between 100 and 200 rpm, preferably 130 to 180 rpm, and a rotation about an axis with an angular velocity ωΐ of 0 to 350 rpm, preferably 50 to 330 rpm. Optionally, the angular velocity ωΐ has an opposite direction to the angular velocity ω2. In other words, the ratio ω1 / ω2 is negative. Preferably, the ratio ranges ωΐ / ω2 from -2.2 to 0. The angular velocities ωΐ and ω2 of the stirring member may be varied during the cooling step.

Once the liquid dairy composition has reached the target temperature, the aeration step c) may begin. The objective of the aeration step is to incorporate air bubbles into the liquid dairy composition and to reach an overrun between about 50% and 150%. The target temperature ranges from 1°C to 8°C, preferably from 1°C to 5°C. The aeration step lasts up to 120 seconds, preferably from 60 to 90 seconds, more preferably from 60 to 85 seconds. The liquid dairy composition is further cooled down to or maintained at a temperature between 1°C and 5°C during the aeration step. For example, the stirring member has a planetary movement with an angular velocity ω2 between 200 and 400 rpm, preferably 250 to 350 rpm, and a rotation about an axis with an angular velocity ωΐ of 500 to 1200 rpm, preferably 600 to 1000 rpm, during the aeration step c). In a preferred embodiment, wherein the angular velocity ωΐ has an opposite direction to the angular velocity ω2 at least during the aerating step. While one runs clockwise, the other runs counter-clockwise. In other words, the ratio ωΐ / ω2 is negative. The angular velocities ωΐ and ω2 of the stirring member may be varied during the aeration step. Advantageously, the process mentioned above may be performed in a single- portion whipping and cooling device as described co-pending application PCT/EP2013/072692 filed on 30 October 2013 and published as WO 2014/067987, or in co-pending application PCT/EP2015/059930 filed on 6 May 2015. This machine comprises:

- a receiving seat, for accommodating a container, comprising a heat exchange element having a heat exchange contact surface arranged to be in contact with an outer surface of a side wall of the container when the container is placed in the machine,

- a cooling unit arranged for cooling the heat exchange element and,

- a stirring unit connectable to a stirring member and arranged for driving the stirring member in at least one rotational movement;

wherein it comprises

- means for measuring the temperature of the product while being prepared, - a control unit for automatically setting output parameters according to input parameters received by the control unit and compared to threshold values stored in the unit;

- wherein the output parameters comprises: at least one rotational velocity of the stirring member and the cooling power of the cooling unit, and

- wherein the input parameters comprises any one or a combination of: the measured product temperature and the stirring time.

The machine preferably has a stirring unit being arranged for driving the stirring member according to a combination of movements, wherein the combination of movement comprises a first rotational movement of the stirring member about its longitudinal axis which is arranged offset to a central longitudinal axis of the receiving seat and/or of the container and wherein the second rotational movement comprises an orbital or planetary rotational movement about the central longitudinal axis of the container or seat and wherein the output parameters comprise the first velocity (ωΐ) of the first rotational movement and the second velocity (ω2) of the second rotational movement of the stirring member. An advantage of such a device is that it does not require injection of a gas under pressure to reach a desired overrun, and it can process a single-portion.

A machine of the above-mentioned type was used in the examples identified with the letters SP.

EXAMPLES

The following illustrate various embodiments of the invention by way of example, and not limitation.

Example 1: Yogurt-type compositions

Three yogurt-type compositions (Recipe Rl, R2 and R3) are prepared according to several embodiments of the invention. A comparative composition (Comparative recipe CR4) is prepared according to a similar process. The final composition and nutritional composition is indicated in Table 1 below. The manufacturing process is shown at Figure 1.

Recipes 1-3 differ by the ratio whey protein concentrate (WPC) / caseins, sugar content, and presence of fruits introduced in the composition during its manufacture. In recipe Rl, R2 and R3, WPC is added in the milk base, before fermentation. Comparative recipe RC4 does not contain whey protein concentrate, contrary to recipes Rl, R2 and R3.

Recipe Rl was prepared first by mixing the milk ingredients. After fermentation, an aqueous HM pectin solution (5% pectin by weight) and an aqueous sugar solution was added to the fermented during storage, before the post-fermentation pasteurisation, as shown on Figure 1.

Recipe R2 was prepared first by mixing the milk ingredients. After fermentation, a dry blend of HM pectin , starches and sugar was added to the fermented during storage, before the post-fermentation heat treatment, as shown on Figure 1. Table 1 - Final connpositions and nutritional analysis

Recipe R3 was prepared as recipe R2. Fruits were added aseptically in the finished product, as shown on Figure 1. Comparative recipe RC4 was prepared using a process as shown on Figure 1, but without addition of WPC. Also, RC4 has a higher fat content than either of recipes Rl, R2, and R3. This is to ensure better foaming of the comparative recipe RC4.

The liquid dairy compositions are shelf-stable under ambient storage conditions. They are non-foamed. They can be used to produce a foamed yogurt-type product using a Kitchen Aid device or a device described in co-pending application PCT/EP2013/072692 filed on 30 October 2013, or in co-pending European patent application EP 14 167344 filed on 7 May 2014.

Example 2: Overrun (%)

"Overrun" refers to the increase in volume of a product due to whipping or foaming. It is also referred to as "foaming capacity". The overrun is measured according to the following equation: (volume of the product after aeration - volume of the product before aeration) / (volume of the product before aeration). In other words, the overrun corresponds to the ratio between the volume of gas and the volume of product before aeration. It is reported as a percentage value.

Whipping of the compositions mentioned in Table 1 was performed with a KITCHENAID Artsan K45 (stainless steel bowl of 4.2L, 250W, voltage: 220/240V) (KA) or with a single-portion whipping and cooling device (SP).

Because the KA device does not have a cooling function, it was necessary to cool down the composition to 4°C in the refrigerator before whipping. In addition, a minimum of 500 g of composition must be poured into the bowl. Whipping was done at speed 5, using the metal whisk during the time mentioned in Table 2 below. If the room temperature was too high, ice packs were placed on the outside wall of the bowl to keep it cool during whipping.

When using the single-portion whipping and cooling device, a volume of 90 mL of the composition was poured into a single-portion processing container and inserted into the device. An 8-wire metal whisk was used during the cooling and aerating (whipping) steps. Initially, the composition was cooled from ambient temperature (about 18°C) to 8°C in about 100 seconds, with a planetary speed of the whisk oo2 of 150 rpm and axial speed of the whisk ool of -300 rpm. Then, the composition was whipped with a planetary speed of the whisk oo2 of 300 rpm and an axial speed of the whisk ool of -800 rpm during 80 seconds. During the whipping step, the temperature of the composition was further reduced from about 8°C to about 4°C.

The overrun was measured immediately after whipping.

Table 2 - Overrun

KA: KITCHEN AID Artsan K45

SP: Single-portion whipping and cooling device described co-pending application PCT/EP2013/072692 filed on 30 October 2013 and published as WO 2014/067987, or in co-pending application PCT/EP2015/059930 filed on 6 May 2015

With a single-portion whipping and cooling device, compositions Rl, R2 and R3, can reach an overrun above 70%, even up to 110% in 1.5 to 2 minutes. With each of these compositions, the single-portion whipping and cooling device provides a greater overrun than the KA device after a 3-minute whipping.

Recipe RC4, which does not contain whey protein concentrate, yields an overrun of 48% after 9 minutes of whipping with the single-portion whipping and cooling device. Hence, it appears that compositions which contain whey protein concentrate can be whipped to an overrun of more than 70% in less than 5 nninutes (about 3 nninutes) and cooled to a chilled temperature of less than 5°C. A foamed yogurt-like product, with a very interesting texture and mouthfeel, can be produced, using the single-portion whipping and cooling device, for immediate consumption and enjoyment.

Example 3: Foam assessment

A foamed yogurt-type product was prepared under the following conditions with the compositions mentioned in Example 1 and the equipment mentioned in Example 2:

Table 3 - Whipping conditions

3.1 Air bubble dispersions analysis by quantitative image analysis

Air bubbles dispersion are prepared as follows:

- Disperse and dilute the foam in a dispersion medium, using from 0.2 to 4 g of product in 20 g dispersion medium). The dispersion medium is made with 5% of solution A (3 parts pure acetone + 1 part glacial acetic acid) in solution B (glycerol 87%).

- Spread an aliquot of the dispersion in an observation chamber.

- Adjust the microscopy settings to get highly contrasted images.

- Capture images to get a sufficient number of air bubbles (about 2000)

- Carry out the dispersion in triplicate.

- Launch the batch analysis. - Collect the data in a Excel file

Figure 2 shows air bubbles dispersions using a quantitative image analysis, from foamed compositions Rl, obtained with either the KA device or with the SP device.

The air bubbles in the foamed recipe Rl are bigger than in the foamed comparative recipe RC4, irrespective of the whipping device used. However, while the mean and median diameter of the air bubbles increase when using the SP device to whip the comparative recipe RC4, using the SP device instead of the KA device yields smaller air bubbles with the recipe Rl. Table 4 - Bubble size measures

3.2 Protein, fat and air distribution imaging by confocal microscopy

Fats are stained with Nile red (Sigma # Sigma N3013), 5 mg/100 ml absolute ethanol. Proteins are stained with Fast green FCF (Serva electrophoresis # SVA2129502) 1% in ethanol. An aliquot of the stained whipped product is placed in a 5 mm deep observation chamber and covered with a cover slide. Confocal imaging is done as follows:

- Nile red: Excitation wavelength = 488 nm; Emission bandwidth= 510-600 nm

- Fast green: Excitation wavelength = 633 nm; Emission wavelength = 640-700 nm Figure 3 is a confocal microscopy picture showing simultaneously the distribution of fat (in red in the pre-conversion figure) and proteins (in green in the pre- conversion figure), in the liquid dairy composition recipes Rl of Example 1 before whipping. Figure 4 are confocal microscopy pictures showing simultaneously the distribution of fat (in red in the pre-conversion figure) and proteins (in green in the pre- conversion figure), in foamed recipes Rl of Example 1 using the KA and SP devices, at two scales: 200 microns (top) or 20 microns (bottom).

When whipping the compositions with the SP device, the protein and fat signals are separate. Fats constitute the major component of the air bubbles interfaces. Proteins are mostly in the continuous phase.

When whipping the compositions with the KA device, the protein and fat signals seem to overlap: fats and proteins are both present at the air bubbles interfaces.

Figure 5 shows are confocal microscopy pictures showing the distribution of fat (in red in the pre-conversion figure) at the air bubbles interface, in the foamed recipe Rl of Example 1 either with the KA device or the SP device, at two different scales. The scales are 200 microns (top) and 20 microns (bottom). It seems that the fat globules at the air bubble interface are larger when using the KA device.

It shows that the SP device imparts a different fat and protein distribution than commercial whipping equipment such as a KA device. SP device is leading to a separated location of proteins and fat in the whipped structure which can be identified by confocal microscopy. Although preferred embodiments have been disclosed in the description with reference to specific examples, it will be recognised that the invention is not limited to the preferred embodiments. Various modifications may become apparent to those of ordinary skill in the art and may be acquired from practice of the invention. It will be understood that the materials used and the chemical details may be slightly different or modified from the descriptions without departing from the methods and compositions disclosed and taught by the present invention.