A process for making a meat analogue product

Background

Almost all commercially available vegetarian and vegan meat analogue food products currently use methylcellulose alone or combined with other additives for achieving optimal binding properties.

Methylcellulose (MC) is the simplest cellulose derivative. Methyl groups (-CH3) replace the naturally occurring hydroxyls at the C-2, C-3 and/or C-6 positions of the cellulose anhydro-D- glucose units. Typically, commercial MC is produced via alkaline treatment (NaOH) for swelling cellulosic fibres to form an alkali-cellulose which would then react with an etherifying agent such as chloromethane, iodomethane or dimethyl sulfate. Acetone, toluene, or isopropanol can also sometimes be added, after the etherifying agent, for tailoring the final degree of methylation. As a result, MC has amphiphilic properties and exhibits a unique thermal behavior which is not found in naturally occurring polysaccharide structures i.e. it gels upon heating.

Gelation is a two step process in which a first step is mainly driven by hydrophobic interactions between highly methylated residues, and then a second step which is a phase separation occurring at T > 60 °C with formation of a turbid strong solid-like material. This gelation behavior upon heating of MC is responsible for the unique performance in cook from raw burgers when shape retention is required upon cooking. It is similar to the performance of an egg white binder.

However, consumers are becoming increasingly concerned about undesirable chemically modified ingredients in their products. Existing solutions for replacing MC involve the use of other additives in combination with other ingredients for achieving desired functionality. Some of those additives also undergo chemical modification during manufacturing to achieve desired functionality.

Carbohydrate based binders can be based on calcium-alginate gels. In order to achieve gelation, a slow acid release (from either glucono-delta-lactone, citric acid, lactic acid) is needed to liberate calcium ions for crosslinking with alginate to form the gel. This process is rather complex to use in application and the functionality is limited to strong, firm gels hence applicable only for specific meat analogues (e.g. sausages).

The use of starch-based binders has a detrimental effect on texture, leading to products with a mushy sensory perception which also crumbles when it is cooked. In addition, starches and flours are high glycemic carbohydrates, which might be not desired or recommended for specific consumer populations (e.g. diabetics or those wishing to limit carbohydrate content).

All of the following meat analogues comprise an additive as part of the binding agent solution. In EP 1 759 593 Al, a minced meat analogue is described containing proteins combined with fibres and an 10 wt% of alginate, pectin and combinations.

In US 2005/0008758A1, the binder comprises hydrogenated fat, water, and a component selected from the group consisting of methylcellulose, modified cornstarch, and a combination thereof.

WO 2016/120594 describes an edible vegan formulation comprising fungal particles, potentially strengthened by presence of calcium ions, hydrocolloids, gluten or a non-wheat based vegetable protein.

Due to all those deficiencies, there are nowadays no plant-based meat analogues that are acceptable for consumers in terms of optimal textural attributes and a more label-friendly, natural ingredient list.

There is a clear need for a plant-based, label-friendly, natural binding agent as an analogue to MC with enhanced functional properties.

Summary of invention

The present invention relates to meat analogue products having a plant based, clean label, natural binding agent as a substitute for methylcellulose and its derivatives (e.g. hydroxypropyl-methylcellulose) in food applications.

The inventors of the present application have surprisingly found a fibre and protein combination that, when mixed under specific conditions in a meat analogue gives a binder or binding agent which has similar functional properties to methylcellulose. The functional properties refer to binding the meat analogue product in cold or room temperature conditions (prior to cooking), hence enabling optimal molding and shape retention during storage while not crumbling on cooking due to the formation of firm gel.

The texture of the product is improved versus alternative binders such as hydrocolloids (e.g. alginate, agar, konjac gum) which tend to give gummy mouthfeel and starches which are perceived as mushy and have the perception of being uncooked. Also, it avoids the use of starch which leads to an undesirable crust formation.

Moreover, the fibre and protein combination when used as a binding agent does not exhibit water leakage during storage of the meat analogue product in the cold. Compared to burgers with binding agents comprising methylcellulose or other hydrocolloids, no water leakage was observed after a 2 week storage period. This is due to the fact that fibres also comprise an insoluble fraction that can bind water via capillary, hence water retention capacity is higher compared to those hydrocolloids that behave as a purely polymer melt.

In addition, a surprising change of color (uniform color transformation from reddish to brown) is found when the meat analogue product of the invention is cooked. This is a desired attribute by consumers expecting a meat-like product. The present invention relates to a process for making a meat analogue product, comprising mixing a plant extract, dietary fibre and protein.

The present invention further relates to a process for making a meat analogue product, comprising hydrating a plant extract, preparing a binding agent by mixing dietary fibre and protein, mixing the plant extract and binding agent, and molding into a shape.

The present invention further relates to a process for making a meat analogue product, comprising

a. Hydrating a plant extract, preferably by mixing with water;

b. Preparing a binding agent by mixing dietary fibre, for example potato fibre, and plant protein;

c. Mixing the plant extract and binding agent; and

d. Molding into a shape.

In particular, the present invention relates to a process for making a meat analogue product, comprising

a. Mixing 15 wt% to 35 wt% plant extract with water;

b. Preparing a binding agent by mixing 0.1 wt% to 10 wt% dietary fibre, for example potato fibre and 0.3 wt% to 10 wt% plant protein;

c. Optionally adding flavor and colorings;

d. Mixing the hydrated plant extract and binding agent; and

e. Molding into a shape.

In one embodiment, 18 wt% to 30 wt% plant extract is mixed with water, preferably about 23 wt% plant extract.

In one embodiment, the plant extract is derived from legumes, cereals or oilseeds.

In one embodiment, the plant extract is derived from soy, pea, wheat or sunflower.

In one embodiment, the plant extract is textured protein preferably made by extrusion.

In one embodiment, the plant extract is derived from soy or pea, preferably textured soy or textured pea.

In one embodiment, the textured soy or textured pea is made by extrusion.

In one embodiment, the dietary fiber at 5 wt. % in aqueous solution at 20°C exhibits the following viscoelastic properties 1) shear thinning behavior with zero shear rate viscosity above 8 Pa.s and 2) G' (storage modulus) greater than 65 Pa and G" (loss modulus) lower than 25Pa of at 1Hz frequency.

In one embodiment, about 0.5 wt% to about 4 wt% dietary fibre is mixed, preferably about 1- 3 wt% fibre is mixed, preferably dry mixed. In one embodiment, not less than 30 wt% of the dietary fibre is soluble, preferably 50 wt% to 70 wt% of the dietary fiber is soluble, preferably about 60 wt%. of the dietary fiber is soluble

In one embodiment, not less than 20 wt% of the soluble fibre is pectic polysaccharide, preferably not less than 40%.

In one embodiment, the dietary fibre is derived from tubers, for example potato, cassava, yam, or sweet potato.

In one embodiment, the dietary fibre is derived from vegetables, for example carrot, pumpkin, or squash.

In one embodiment, the dietary fibre is derived from fruit, for example citrus fruit.

In one embodiment, the dietary fibre is derived from legumes, for example pulses.

In one embodiment, the dietary fibre is derived from oilseeds, for example flaxseed.

The dietary fiber can be derived from potato, apple, psyllium, fenugreek, chickpea, carrot, flaxseeds or citrus fruit.

In one embodiment, the dietary fibre is derived from potato, fenugreek, citrus, or psyllium.

In one embodiment, the dietary fiber comprises potato fibre. In one embodiment, the dietary fiber is derived from potato and psyllium, for example Hi Fibre 115.

In one embodiment, about 0.5 wt% to about 10 wt% plant protein is mixed, or dry mixed.

In one embodiment, about 0.5 wt% to about 5 wt% plant protein is mixed, or dry mixed.

In one embodiment, the plant protein gels upon heating at a temperature at or above 50°C. The person skilled in the art will know that minimal gelling concentration of a protein depends on pH, ionic strength and heating kinetics.

For example, a potato protein heated for about 30 minutes at 70°C may gel at 3% at pH 7, while in the presence of lOmM NaCI, the same protein can also gel at 2% concentration under the same conditions.

In one embodiment, the plant protein is at least partially native.

In one embodiment, the meat analogue product is a burger and the plant protein is potato protein, preferably about 1 wt% to about 3 wt% potato protein.

In one embodiment, beetroot based color is added.

In one embodiment, the meat analogue product is substantially free of hydrocolloids.

In one embodiment, the meat analogue product is substantially free of modified starches.

In one embodiment, the meat analogue product is substantially free of emulsifiers.

In one embodiment, the meat analogue product is substantially free of additives In one embodiment, a fat source and/or oil are added to the plant extract and binding agent mixture.

Also provided is a meat analogue product obtainable by the process of the invention, wherein said product is a burger, sausage, minced meat, meatballs or cold cuts.

Also provided is a meat analogue product comprising

a. Plant extract;

b. Flavoring;

c. Fat; and

d. Binding agent

wherein the plant extract is selected from soy, pea, and gluten and wherein the binding agent comprises 0.1 wt% to 10 wt% dietary fibre and 0.3 wt% to 10 wt% plant protein.

Also provided is a meat analogue product comprising

a. Plant extract;

b. Flavoring;

c. Fat; and

d. Binding agent

wherein the plant extract is selected from soy, pea, wheat, and sunflower and wherein the binding agent comprises 0.1 wt% to 10 wt% dietary fibre and 0.3 wt% to 10 wt% plant protein, and wherein not less than 50 wt% of the dietary fibre is soluble.

In one embodiment, not less than 20 wt% of the soluble fibre is pectic polysaccharide, preferably not less than 40%.

In one embodiment, the plant extract is textured soy.

In one embodiment, the binding agent comprises more than 50% soluble fibre and plant protein.

In one embodiment, the binding agent comprises potato fibre and potato protein.

In one embodiment, the binding agent is substantially free of hydrocolloids.

Also provided is a meat analogue product comprising: 15 wt% to 30wt% soy extract, preferably about 20 wt% soy extract; about 2 wt% potato fibre; 1 to 3 wt% potato protein; fat source; water; beetroot powder; flavoring; and salt

Also provided is a meat analogue product comprising: 15 wt% to 30wt% soy extract, preferably about 20 wt% soy extract; about 2 wt% potato fibre; 1 to 3 wt% potato protein; 3 - 15 wt% fat source; water; beetroot powder; flavouring; and salt. Also provided is a meat analogue product comprising: 20 wt% to 30wt% soy extract, preferably about 23 wt% soy extract; about 3 wt% potato fibre; about 2 wt% potato protein; 3 - 15 wt% fat source; water; beetroot powder; flavouring; and salt.

Also provided is a meat analogue product comprising: 20 wt% to 30wt% soy extract, preferably about 23 wt% soy extract; about 3 wt% potato fibre; about 1 to 3 wt% potato protein; 3 - 15 wt% fat source; water; beetroot powder; flavouring; and salt.

Also provided is a meat analogue product comprising: 20 wt% to 30wt% soy extract, preferably about 23 wt% soy extract; about 3 wt% potato fibre; about 2 wt% potato protein; 3 - 15 wt% fat source; water; beetroot powder; flavouring; and salt.

Also provided is a meat analogue product comprising: 20 wt% to 30wt% soy extract, preferably about 23 wt% soy extract; about 1 wt% potato fibre; about 1 to 3 wt% potato protein; 3 - 15 wt% fat source; water; beetroot powder; flavouring; and salt.

Also provided is a meat analogue product comprising: 15 wt% to 30wt% pea extract, preferably about 20 wt% pea extract; about 1 wt% potato fibre; about 3 wt% potato protein; 3 - 15 wt% fat source; water; beetroot color; flavouring; and salt.

Also provided is a meat analogue product comprising: 15 wt% to 30wt% pea extract, preferably about 20 wt% pea extract; about 1.5 wt% potato fibre; about 3 wt% potato protein; 3 - 15 wt% fat source; water; beetroot color; flavouring; and salt

Also provided is a meat analogue product comprising: 15 wt% to 30wt% pea extract, preferably about 20 wt% pea extract; about 1 wt% potato fibre; about 2 wt% potato protein; 3 - 15 wt% fat source; water; beetroot color; flavouring; and salt

Also provided is a meat analogue product comprising: 15 wt% to 30wt% sunflower extract, preferably about 20 wt% pea extract; about 1 wt% potato fibre; about 3 wt% potato protein; 3 - 15 wt% fat source; water; beetroot color; flavouring; and salt.

Also provided is a meat analogue product comprising: 15 wt% to 30wt% sunflower extract, preferably about 20 wt% pea extract; about 1.5 wt% potato fibre; about 3 wt% potato protein; 3 - 15 wt% fat source; water; beetroot color; flavouring; and salt

Also provided is a meat analogue product comprising: 15 wt% to 30wt% sunflower extract, preferably about 20 wt% pea extract; about 1 wt% potato fibre; about 2 wt% potato protein; 3 - 15 wt% fat source; water; beetroot color; flavouring; and salt

Also provided is the use of a binding agent in a meat analogue product, wherein the binding agent comprises 0.1 wt% to 10 wt% dietary fibre and 0.3 wt% to 10 wt% plant protein.

In one embodiment, the binding agent is substantially free of hydrocolloids.

In one embodiment, the binding agent is substantially free of modified starches.

In one embodiment, the binding agent is substantially free of emulsifiers.

In one embodiment, the plant protein is at least partially native. In one embodiment, the binding agent comprises about 0.5 wt% to about 4 wt% dietary fibre.

In one embodiment, not less than 50 wt% of the dietary fibre is soluble, preferably 50 wt% to 70 wt% of the dietary fiber is soluble, preferably about 60 wt%. of the dietary fiber is soluble

In one embodiment, not less than 20 wt% of the soluble fibre is pectic polysaccharide, preferably not less than 40%.

In one embodiment, the dietary fibre is derived from tubers, for example potato, cassava, yam, or sweet potato.

In one embodiment, the dietary fibre is derived from vegetables, for example carrot, pumpkin, or squash.

In one embodiment, the dietary fibre is derived from fruit, for example citrus fruit.

In one embodiment, the dietary fibre is derived from legumes, for example pulses.

In one embodiment, the dietary fibre is derived from oilseeds, for example flaxseed.

The dietary fiber can be derived from potato, apple, psyllium, fenugreek, chickpea, carrot, flaxseeds or citrus fruit.

In one embodiment, the dietary fibre is derived from potato, fenugreek, citrus, or psyllium.

In one embodiment, the dietary fiber is potato fibre. In one embodiment, the dietary fiber is derived from potato and psyllium.

In one embodiment, the binding agent comprises about 0.5 wt% to about 5 wt% plant protein.

In one embodiment, the binding agent comprises about 2 wt% to about 4 wt% potato fibre and about 1 wt% to about 3 wt% potato protein.

In one embodiment, the meat analogue product is a burger and the plant protein is potato protein, preferably about 1 wt% to about 3 wt% potato protein.

In one embodiment, beetroot based color is added.

In one embodiment, the meat analogue product is substantially free of additives

In one embodiment, the meat analogue comprises a fat source and/or oil.

The meat analogue product may be a burger, sausage, minced meat, meatballs or cold cuts.

Detailed description of the invention

Plant fibre

In one embodiment, a Newtonian fluid behavior is observed at low concentrations when the plant fibre component of the binding agent is dispersed in water (below 1 wt%). In one embodiment, a shear thinning response becomes apparent at concentrations equal or above 1 wt% when dispersed in water.

A water based solution comprising 5 wt% of plant fibre at 20°C may exhibit the following viscoelastic properties (i) shear thinning behavior with zero shear rate viscosity above 8 Pa.s, and (ii) G' (storage modulus) greater than 65 Pa and G” (loss modulus) lower than 25Pa of at 1Hz frequency. Within the scope of this invention, the shear thinning is defined as any material that exhibits a decrease in viscosity with increasing shear rate or applied stress.

In one embodiment, modulus G' is greater than the modulus G” up to and including at least 100% of applied strain, at concentrations of 5 wt% when dispersed in water.

Plant protein

In one embodiment, the plant protein component of the binding agent comprises proteins that form a gel upon heating above 50°C. The person skilled in the art knows that gelling is protein concentration and conditions dependent. In one embodiment, the binding agent comprises at least partially native proteins that have onset temperature for denaturation (Tonset) in near neutral conditions and 10% protein (w/w) concentration at about 60 °C. In one embodiment, the endothermic peak of the plant protein component of the binding agent is between 60°C to 90°C, or 70°C to 80°C. This is important for gelling during cooking.

The preferred plant protein of the binding agent is potato protein.

Method of making the meat analogue product

The meat analogue product of the invention can be made or prepared according to the following method: a) develop gluten with water, vinegar and ascorbic acid into a relaxed, viscous liquid like mass as described in US Patent 4938976 (Nestle/Tivall); b) hydrate textured protein (for example soy, pea, gluten, sunflower or combination thereof) with water and optional other ingredients (e.g. vinegar, color mix, natural antimicrobial); c) combine all dries (protein/fibre mix, salt, flavoring, optional dried beetroot color); d) mix developed gluten, textured soy, and dries until the ingredients are distributed equally (if developed gluten is present, until gluten is incorporated into the mix as fine strands); e) add fat flakes (coconut fat or other suitable fat solid at 15°C); f) form patties, refrigerate or freeze until testing; g) test by cooking on hot plate (griddle) at about 175°C (about 350°F) for 10-12 min.

The meat analogue product of the invention can be made or prepared according to the following method:

a) develop gluten with water, vinegar and ascorbic acid into a relaxed, viscous liquid like mass as described in US Patent 4938976 (Nestle/Tivall); b) mix water, protein powder, vinegar, color mix, natural antimicrobial; c) hydrate textured protein (for example soy, pea, gluten, sunflower or combination thereof) with the water dispersion; d) combine remaining dries (fibre, salt, flavoring); e) mix developed gluten, textured soy, and dries until the ingredients are distributed equally (if developed gluten is present, until gluten is incorporated into the mix as fine strands); f) add fat flakes (coconut fat or other suitable fat solid at 15°C); g) form patties, refrigerate or freeze until testing; h) test by cooking on hot plate (griddle) at about 175°C (about 350°F) for 10-12 min.

Definitions

The term "wt%" used in the entire description below refers to total weight % of the final product. The final composition included water unless specified. The recipes in the examples show an illustration of how wt% is to be understood by the skilled person in the art.

As used herein, "about," "approximately" and "substantially" are understood to refer to numbers in a range of numerals, for example the range of -40% to +40% of the referenced number, more preferably the range of -20% to +20% of the referenced number, more preferably the range of -10% to +10% of the referenced number, more preferably -5% to +5% of the referenced number, more preferably -1% to +1% of the referenced number, most preferably -0.1% to +0.1% of the referenced number. All numerical ranges herein should be understood to include all integers, whole or fractions, within the range. Moreover, these numerical ranges should be construed as providing support for a claim directed to any number or subset of numbers in that range. For example, a disclosure of from 1 to 10 should be construed as supporting a range of from 1 to 8, from 3 to 7, from 1 to 9, from 3.6 to 4.6, from 3.5 to 9.9, and so forth.

The term "additive" includes one or more of modified starches, hydrocolloids (e.g. carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, konjac gum, carragenans, xanthan gum, gellan gum, locust bean gum, alginates, agar, gum arabic, gelatin, Karaya gum, Cassia gum, microcrystalline cellulose, ethylcellulose); emulsifiers (e.g. lecithin, mono and diglycerides, PGPR); whitening agents (e.g. titanium dioxide); plasticizers (e.g. glycerine); anti-caking agents (e.g. silicon-dioxide).

The terms "food", "food product" and "food composition" mean a product or composition that is intended for ingestion by an animal, including a human, and provides at least one nutrient to the animal or human. The present disclosure is not limited to a specific animal.

A "meat-analogue" is also called a meat alternative, meat substitute, mock meat, faux meat, imitation meat, or (where applicable) vegetarian meat or vegan meat. Meat analogue is understood to mean a food made from non-meats, without other animal products, such as dairy. Therefore protein from animal source is completely absent. Protein from animal source is animal meat protein and/or milk protein. A meat-analogue food product is a composition in which meat (i.e. skeletal tissue and non- skeletal muscle from mammals, fish and fowl) and meat by-products (i.e. the non-rendered clean parts, other than meat, derived from slaughtered mammals, fowl or fish) are completely absent. The market for meat imitations includes vegetarians, vegans, non-vegetarians seeking to reduce their meat consumption for health or ethical reasons, and people following religious dietary laws. The term "plant protein" includes "plant protein isolates" or "plant protein concentrates" or combination thereof. The person skilled in the art knows how to calculate the amount of plant protein within a plant protein concentrate or plant protein isolate.

The term "binder" or "binding agent" as used herein relates to a substance for holding together particles and/or fibres in a cohesive mass. It is an edible substance that in the fina l product is used to trap components of the foodstuff with a matrix for the purpose of forming a cohesive product and/or for thickening the product. Binding agents of the invention may contribute to a smoother product texture, add body to a product, help retain moisture and/or assist in maintaining cohesive product shape; for example by aiding particles to agglomerate.

The term "fibre" or "dietary fibre" relates to a plant-based ingredient that is not completely digestible by enzymes in the human gut system. The term may comprise plant based fibre-rich fraction obtained from vegetables, seeds, fruits, nuts, pulses. The dietary fibre may comprise cellulose, hemicellulose, pectin, B-glucans, arabinoxylans, galactomannans, mucilages and lignin. In one embodiment, the dietary fibre is a fibre with a soluble polysaccharide fraction greater than 50 wt%. In one embodiment, the soluble polysaccharide fraction comprising pectins as main polysaccharide component of the soluble fraction and may contain residual starch and protein. In one embodiment, the soluble fraction comprises arabinoxylans. In one embodiment, the dietary fibre can be derived from potato, apple, psyllium, fenugreek or citrus. The dietary fibre of the invention typically exhibits the fibre rheology characteristics in water based solutions shown below.

The term "textured protein" as used herein refers to plant extract material, preferably derived from legumes, cereals or oilseeds. For example, the legume may be soy or pea, the cereal may be gluten from wheat, the oilseed may be sunflower. In one embodiment, the textured protein is made by extrusion. This can cause a change in the structure of the protein which results in a fibrous, spongy matrix, similar in texture to meat. The textured protein can be dehydrated or non-dehydrated. In its dehydrated form, textured protein can have a shelf life of longer than a year, but will spoil within several days after being hydrated. In its flaked form, it can be used similarly to ground meat.

Brief description of figures

Figure 1. Apparent viscosity (Pa.s) of potato fibre water dispersions as a function of shear rate (s ¹ ) at a range concentrations, at 20°C.

Figure 2. Strain sweeps for 5 wt% potato fibre water dispersions, measured at constant Frequency of 1 Hz, at 20°C.

Figure 3. Mechanical spectra of potato protein gel (PP1) and ovalbumin (OA) gel obtained after heating protein dispersion at 3 wt% and 4 wt% at 85°C for 15 min in presence of NaCI 0.1M. Filled symbols correspond to elastic modulus G' and empty symbols to storage modulus G”. Key: dark squares - PP1 (4 wt%); light squares - OA (4 wt%); light triangles - PP1 (3 wt%); and dark triangles - OA (3 wt%).

Figure 4. G' as function of temperature for 6%, 14% potato protein solutions

Figure 5. Minimal gelling concentration determination of potato protein isolate at pH 7, heated 30' at 70°C, Minimal gelling concentration is indicated by gray number. The value considered as the minimal gelling concentration is the concentration where the sample stayed at the bottom of the vial (i.e. did not slide down), when they were turned upside down.

2% potato protein dispersions heated 30' at 70°C at pH 7 or 4, alone or in the in the presence of various concentrations of NaCI (indicated below the picture). Gels are indicated by the grey number. Gel is considered where vial the sample stayed at the bottom of the vial (i.e. did not slide down), when they were turned upside down.

Figure 6. DSC thermogram of two potato protein isolates (PP1 and PP2)

Figure 7. Cooked burger patties made with texturized pea protein containing 2% wt methylcellulose or 1% wt potato fiber combined with 0.5, 0.75 and 1% wt potato protein.

Figure 8. Burger patty made with textured pea/gluten protein obtained by high moisture extrusion, containing 1.5% wt fiber and 3% wt potato protein in the final mixture, before and after cooking.

EXAMPLES

Example 1: Rheological behavior of potato fibre

Potato fibres (Hi Fibre 115, according to supplier specification comprises about 92% total fibre, about 2% protein, wherein 98% of the ingredient is derived from potato source and about 2% of the ingredient is derived from soluble psyllium husk) were selected based on their rheological response when dispersed in water. The desired functionality from the fibre is mostly related to binding of the meat pieces, hence enabling molding into burger shape that does not crumble as well as preventing water leakage during cold storage.

Figure 1 shows shear viscosity of potato fibre dispersions at a range of concentrations. A Newtonian fluid behavior is observed at low concentrations (below 1 wt%) whereas a shear thinning response becomes apparent at concentrations equal or above 1 wt%. The onset concentration for shear thinning response for this potato fibre is rather low compared to fibres comprising large amounts of insoluble polysaccharides (e.g. cellulose, hemicellulose). This is mainly due to the increased amount of soluble, high molecular polysaccharide chains from the potato fibre (primarily galacturtonic and glucuronic type, but also glucans, mannoses, xyloses, rhamonoses and arabinoses) which are solubilized in the water continuous phase and hence occupy large hydrodynamic volumes.

The viscoelastic properties of 5 wt% potato fibre water dispersions are shown in Figure 2, with G' being significantly greater than G" and constant over wide range of applied strain (corresponding to the linear viscoelastic region) until the microstructure breaks down and the material yields. The fact that potato fibre dispersions show G' > G" indicates the dominant solid-like response over the applied strain ranges, which is attributed to the chain entanglement between the previously mentioned polysaccharides that are solubilized in the water-continuous phase. The insoluble fibre fraction of the potato fibre is acting as a filler, with less contribution to the viscoelastic response of the fibre suspension.

This particular viscoelastic response is not measured when fibres with greater insoluble fraction (comprising primarily cellulose, hemicellulose, and lining) are used at the same concentration. Those fibres behave as particulate dispersions in which insoluble fibre particles have the tendency to sediment thereby displaying lower viscosity values and without any elastic contribution at equal concentration ranges. For these insoluble fibre rich ingredients, increased concentrations are needed for the particulate dispersions to exhibit solid-like behavior. This occurs when the suspensions are densely packed, with an effective phase volume greater than their maximum packing fraction which leads to solid-like linear viscoelastic response that exhibits flows only if a sufficient shear stress is applied (i.e. the yield stress).

Example 2: Rheological properties of potato protein

Mechanical spectra of potato protein gels

Gelling properties of potato protein isolate PP1 from a commercial source and ovalbumin from a commercial source were compared using small deformation rheology. Gelation of protein dispersion was performed in situ in an Paar Physica MCR501 (Anton Paar Ostfildern, Germany) stress-controlled rheometer, using a concentric cylinder setup (inner and outer cylinder are 8.33 and 9.04 mm respectively). The rheomether was equipped with a Peltier heating and cooling device. Protein dispersion was placed in the geometry and a thin layer of paraffin oil was carefully placed on top to prevent evaporation during the experiment.

The temperature was raised from 20 °C to 85 °C at 5 °C/min. After 15 minutes holding at 85 °C, the temperature was decreased to 20 °C at -5 °C/min. After reaching 20 °C, the system was left to equilibrate at 0.05% strain and 1 Hz for 10 minutes. A frequency sweep was subsequently performed. Figure 3 shows the mechanical spectra obtained after cooling. All systems formed strong gels with G' value being higher than G" over the whole frequency range with a decade of difference between the two moduli.

Interestingly this first screening showed that similar profiles were obtained for PP1 and Ovalbumin at 3 wt% and 4 wt% protein in the presence of 0.1M NaCI suggesting similar gel strengths.

G' for 6%, 14% potato protein solutions as function of temperature, at pH= 6.

A solution of potato protein was prepared by dispersing the protein in a degassed water and stirring overnight. The pH was adjusted to pH of 6 using HCI.

Evolution of G' was measured as function of temperature in stress-controlled rheometer (MCR 502, Anton Paar) with a sandblasted concentric cylinder geometry. Samples were placed and left to stabilize for 5 minutes at 20°C. After that, the following heating/cooling sequence was applied: heating ramp from 20°C to 90°C at 5°C/min, holding at 90°C for 20 minutes, followed by cooling from 90°C to 20°C at 4°C/ min. Measurements were carried out at a constant strain of 0,5% and a constant frequency of 1Hz (Figure 4).

In order to prevent evaporation, the samples were covered using mineral oil during rheological measurements.

Minimal gelling concentration of potato protein determination

Dispersions having increasing protein concentrations were prepared by dissolving corresponding amount of potato protein isolate in Millipore ^® water. Subsequently pH was adjusted to 4 or 7 by using 1M and 2M HCI or NaOH. After preparation, 3 mL of each sample was transferred into a 4 mL glass vial with screw-cap and heated in a water bath without stirring. Samples were heated 30 minutes at at 70°C. After cooling on ice, the sol - gel transition of the samples was analysed using the 'tilting-test', i.e. vials with samples were turned upside down and when the sample stayed at the bottom of the vial (i.e. did not slide down), it was considered as a gel.

The minimal gelling concentration in the presence of lOmM NaCI at pH 7 decreased to 2% protein while at pH 4 20mM NaCI had negative impact on gel formation.

To test the influence of salt addition on minimal gelling concentration, 2M NaCI solution was prepared and added in different amounts to chosen protein dispersions to achieve lOmM and 20mM NaCI.

Example 3: Denaturation temperature of potato protein isolates

Heating causes denaturation of proteins as a result of disruption of bonds that are involved in the formation and maintenance of the protein structure. Denaturation temperatures of potato protein isolates were determined by differential scanning calorimetry (DSC). Presence of endothermic peaks observed in thermograms (figure 6) suggest that both evaluated potato protein isolates (PP1 and PP2) contain native proteins that denature upon heating above 65°C.

Example 4: Textured soy recipes

Water was added to textured soy in a Hobart mixer and stirred until properly hydrated. Salt, color and savory powders were dry mixed separately and then added to the hydrated texturized protein. Canola oil and methylcellulose, fibre or fibre/protein combination were then added to the mixture, which was subsequently hand mixed until homogeneous appearance.

Shea/coconut fat flakes were then incorporated and the final mixture was gently mixed by hand, molded to a burger shape and kept in the fridge (4 °C) overnight. Molding was done for 100 g of the mix using a round mold. The next day, burgers were cooked by first searing the burger both sides in a skilled pan and cooked in the oven at 180°C for 12 minutes.

(All values expressed in the above table are wt%)

Example 5: Results obtained with the textured soy Based on the performance of all the evaluated recipes, i.e. their ability to be molded into burgers, shape retention during cooking, appearance and sensory characteristics, the combination of 3 wt% potato fibre and 2 wt% potato protein has been identified as the most promising solution.

Example 6: Burger molding and storage in cold conditions

Molding burgers into appropriate shape was not possible for samples which only contained protein as a binder. This is mainly due to a reduced viscosity of the protein-water solutions compared to the methylcellulose solution at the same concentration in cold conditions.

All recipes containing fibres or fibre-protein combinations could be molded into burgers the same way as with methylcellulose and were stable upon storage at 4°C (no water leakage was observed after 2 weeks storage).

Example 7: Burger cooking

Burgers containing higher amount of fibres (4 wt%) and burgers with fibre-protein combinations as a binder retained the structure upon pan-searing and oven cooking.

Interestingly, burgers containing protein in the recipe showed a significant color change, browning upon searing, which did not occur with either methylcellulose or fibres alone. This effect is most likely due to Mallard reaction occurring between protein and the sugar from the beetroot-based Fiesta colorant.

Example 8: Panel tasting of burgers

Tasting of burgers was performed with 8 panelists.

• Methylcellulose reference was described as somewhat dry.

• Samples containing only higher amount of fibre (4 wt%) had a quite/too crunchy surface.

• Most of the panelists liked recipes containing potato fibre and protein combinations.

The best burger was the one containing 3 wt% of potato fibre and 2 wt% of potato protein - described as having the best texture by far (better than the methylcellulose reference) and somewhat meaty taste. Second best was the burger with 3 wt% of potato fibre and 2 wt% of soy protein (SP1).

• Samples containing 2 other fibres were perceived as gummy by 2 panelists or as presenting some off-flavors, mouth/tongue coating and were described as somewhat slimy. Samples containing soy protein and potato fibre were cohesive but perceived as soft in texture.

Samples containing only protein as a binder could not be molded, mainly due to a reduced viscosity of the protein-water solutions compared to the methylcellulose solution at the same concentration in cold conditions.

Example 9 Textured pea recipes

Water was added to textured pea in a Hobart mixer and stirred gently until properly hydrated. Vinegar, colors, flavors and spices were then added to the hydrated texturized protein. Canola oil was added as well. This mass was used as a base for different recipes. To the adequate amount of the base, methylcellulose or fibre/protein combinations were added and mixed. Fat flakes were added at the end and the final mixture was gently mixed by hand, molded to a burger shape and kept in the fridge (4 °C) until cooking. The burgers were cooked in a skilled pan on both sides until internal temperature was over 70°C.

All patties were shapeable and retained the form upon cooking. Only the patty containing methylcellulose shrank upon cooking, was sticking to the pan and burned ring was formed around it due to the fluid leaking (figure 7). The texture of all patties was acceptable, with the exception of the one containing gluten and faba bean proteins that was described as mushy. The hemp protein recipe was less firm than the potato protein recipe but less mushy than the faba protein recipe.

(All values expressed in the above table are wt%)

Example 10

Pea/gluten protein textured by high moisture extrusion was mixed with vinegar, colors, flavors and spices in the similar ratio as in the example 9. Separately, potato protein water dispersion was mixed with the oil and then potato fiber was added to form a highly viscous paste. This paste was added to the textured protein mass to achieve 1.5% wt fiber and 3% wt potato protein in the final mixture. Fat flakes were added at the end and the final mixture was gently mixed by hand, molded into a burger shape and kept in the fridge (4 °C) until cooking. The burgers were cooked in a skilled pan on both sides until internal temperature was over 70°C. The patties were easily shapeable and retained the form upon cooking. Upon tasting, the patties were described as having a firm bite. Figure 8 shows burger patty made with textured pea/gluten protein obtained by high moisture extrusion, before and after cooking.