GB2565178B

GB2565178B - Egg gel food additive

Info

Publication number: GB2565178B
Application number: GB1805970.9A
Authority: GB
Inventors: Pakdel Saeed
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-04-11
Filing date: 2018-04-11
Publication date: 2019-07-31
Anticipated expiration: 2038-04-11
Also published as: GB201805970D0; GB2565178A

Description

EGG GEL FOOD ADDITIVE

The present invention relates generally to an egg gel food additive composition, methods for preparing the egg gel and food products prepared using the egg gel. In particular, the present invention is directed towards an egg gel composition for use in food products as a replacement for fresh egg or egg powder.

Egg is a commonly used component of many food products and has a variety of functions in addition to contributing to organoleptics, including binding ingredients together, leavening baked goods, acting as a thickening agent and acting as an emulsifier.

When food compositions are whipped, air bubbles are formed in the composition. When these air bubbles are trapped and stabilised in the mixture, a foam is formed. This foam is stabilised when egg is present as the proteins present in the egg denature upon whipping and stabilise the air bubbles. The leavening properties of egg are thus the result of this feature of the egg component, whilst the proteins present in egg also cause the observed emulsifying properties.

When eggs are used in the food industry, they must be washed and disinfected thoroughly before being broken in order to prevent microbial contamination. Additionally, the lifetime of an egg is short, which can cause problems with storage and food production. For these reasons, egg powder is commonly used in industry as it can be stored for up to one year. Egg powder is fully dehydrated egg which may be made, for instance, using spray drying methods. In the formation of egg powder from egg, the product loses its emulsifying and foaming properties, even once rehydrated, and the rheological features of the egg are lost. For this reason, an improved egg-containing product with an extended storage life which retains the properties of egg is desirable.

The reduction in the water content of a product can extend the shelf life by reducing microbial growth. Egg concentrates have been formed by evaporation of water from eggs, without complete water removal, with examples typically having a water content in the range of approximately 15 to 30 wt.%. Normally, egg concentrates have poor preservation properties and are, therefore, difficult to store in concentrated form for a long period of time without losing their original organoleptic qualities (e.g. taste, smell, etc). US 3,409,446 relates to an egg-sugar concentrate which may be preserved and stored for long periods without deterioration, the sugar content decreasing decomposition of the egg. The process involves time consuming evaporation of the composition, with the final concentrate proving to be unstable due to crystallisation of the sugar after about 3 months. US 5,028,448 discloses an egg concentrate containing egg and sugar, with glycerol, alginate and maltodextrin present to prevent crystallisation of the sugar, which claims to have a shelf life of up to 6 months to a year. In these compositions, the addition of large quantities of sugar (egg:sugar mass ratio of about 2:1) limits the use of the concentrate to sweet foods. Additionally, the evaporation procedure requires the use of fresh eggs and is time consuming, ranging from 2 to 3 days, making it a labour intensive process.

There remains a need for egg replacement products which are storage stable over an extended time period and which retain the organoleptic properties of egg, in particular the taste, whilst providing desirable emulsifying and foaming properties not associated with conventional egg powders. The use of egg powder in the production of such products, as opposed to fresh egg, is nevertheless still desirable due to the difficulty in dealing with fresh eggs, as detailed above.

This invention relates to an egg gel food additive comprising glycerol, propylene glycol, egg powder, fat, a non-alpha-tending emulsifier and an alpha-tending co-emulsifier. It has surprisingly been found that this particular combination of ingredients results in an gel product which is shelf stable against microorganic decomposition, to the extent that the necessity of further treatments to provide bacteriostasis and protection against development of moulds is obviated. The egg gel also provides the emulsifying and whippable and/or foamable properties of egg whilst being formed from egg powder. The egg gel also retains an acceptable egg flavour and may be used as an egg or egg powder replacement in a variety of food types without adversely affecting the organoleptics, particularly taste.

Reference to “egg” in this application is intended to mean “fresh egg” unless the definition is otherwise specified, for instance as “egg powder” or “egg gel”.

Gels are typically defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state. By weight, gels are mostly liquid, yet behave like solids due to a three-dimensional cross-linked network within the liquid. It is the crosslinking within the fluid that gives a gel its structure (hardness) and contributes to the adhesive stick (tack). In this way gels are a dispersion of molecules of a liquid within a solid in which liquid particles are dispersed in the solid medium. Reference to “egg gel” herein is intended to mean a gel, as defined above, comprising egg powder, the protein component of which is believed to contribute to the three-dimensional cross-linking characteristic of the gel. A “food additive” is a product which may be included as an ingredient in a food product. The food additive may confer a variety of beneficial properties on the resulting food product, including desirable organoleptics and emulsifying/stabilising properties. “Egg-containing products” are food products which comprise raw egg, egg powder, the egg gel of the present invention or any other form of egg. A food product comprising the egg-gel of the present invention, or prepared using the egg-gel of the invention, may take a variety of different forms and may generally be employed in food products typically prepared using egg powder and/or egg. Examples of such egg-containing products include baked goods such as cakes, breads, cookies, pie shells, muffins, turnovers, pancakes, waffles, donuts, souffles, and meringues, as well sauces such as mayonnaise and creams of various forms. “Whippable” or “foamable” used herein is intended to refer to the ability of a food product to be converted to a stable whipped or foamed product following the entrainment of an inert gas / air in the food product through the action of whipping or foaming.

The microbial stability of food products is based upon the principles of water activity (Aw), the amount of free water available to bacteria. Under certain values of Aw, microbes are unable to survive and thus the product becomes stable during storage conditions.

Water in food interacts with the other components of the food product and may be bound by these components, for example, it may be bound to ions as water of hydration, or bound to surfaces of large molecule or cell structures. These interactions between water and the other components of a food product may include intermolecular interactions such as hydrogen bonding, van der Waals interactions and electrostatic interactions such as dipole-dipole and ion-dipole forces. This bound water is not free to support microbial growth, or to participate in or support chemical or enzyme reactions and spoilage processes. The total amount of bound water in a food has no relation to food stability.

Water that is not bound is called free water. The free water in a food may support microbial growth, and may participate in and support chemical and enzymatic reactions and spoilage processes. It is the amount of free water which determines the Aw, and it is more important for food stability, chemical and microbial, than the total water content. When the water in a food is bound, its tendency to evaporate is reduced and the vapour pressure of the substance is reduced. This provides a means of defining and measuring the amount of free water.

The Aw value is the partial vapour pressure of water in a substance divided by the standard state partial vapour pressure of water. In the field of food science, the standard state is most often defined as the partial vapour pressure of pure water at the same temperature that the partial vapour pressure of water in the substance was measured at. Using this definition, pure distilled water has a water activity of exactly 1. The Aw value of a substance may be determined by placing a sample in a container which is then sealed, and after equilibrium is reached determining the relative humidity above the sample. An example of a suitable apparatus for determining Aw is the LabMaster-aw by Novasina.

The lower the Aw value, the more stable the food product is against microbiological decomposition, e.g., 0;80 Aw in a product indicates more stability than 0.90 Aw in a similar type product. Most enzymes are inactivated at an Aw below 0.85. Bacteria usually require an Aw of at least 0.91, and fungi at least 0.7 to grow and reproduce. A reduction of Aw below 0.6 will inhibit all growth of bacteria, yeasts and mould. The Aw may be reduced through the addition of substances which bind water. The novel egg gel of this invention is characterised by an Aw of below 0.6. The egg gel of the present invention may have an Aw of less than 0.5 or less than 0.4. In preferred embodiments, the egg gel of the present invention has an Aw of from 0.2 to 0.5, more preferably from 0.3 to 0.4. The low free water content of the egg gel is believed to result in the observed stability against microorganic decomposition.

The Aw of the egg gel may be modified by changing the ingredients and/or the water content. A low water content is more likely to result in a low Aw as more of the water is likely to be bound water as opposed to free water, and thus may result in a longer storage lifetime. It should be noted that the Aw is dependent upon many other features of the composition, with the water content being only one contributing factor. Water present in the egg gel of the present invention may be naturally present in low quantities in the ingredients of the egg gel and thus may not be provided as a result of an addition step during the preparation of the egg gel as an isolated ingredient.

The reduction in the water content of the egg gel may extend its shelf life, for the reasons discussed above. Preferably, water is present in the egg gel in the lowest possible quantities. Typically, the egg gel of the present invention may have a water content of less than 5 wt. %, preferably less than 2 wt.%, more preferably less than 1 wt.%, even more preferably less than 0.5 wt.%, most preferably less than 0.1 wt.% water content.

It has been found that the particular combination of ingredients in the egg gel of the present invention results in surprisingly good shelf life. When the egg gel is used in the preparation of food products, it produces egg-containing products with rheology, foaming and/or whipping properties particularly similar to those provided by raw egg. Therefore, the egg gel of the present invention is particularly suitable as a fresh egg substitute than egg powder alone.

As described above, the egg gel food additive of the invention comprises glycerol, propylene glycol, egg powder, fat, a non-alpha-tending emulsifier and an alpha-tending co-emulsifier.

Polyhydric alcohols having two or more hydroxyl groups such as glycerol and propylene glycol and mixtures thereof are present in the egg gel. Without being bound by theory, in some instances it is believed that these polyhydric alcohols can assist in reducing the water content of the egg gel by substituting for a portion of the water present in the interior of the product and causing water transfer to the exterior thereof. This reduces the quantity of water in the egg gel and may reduce the amount of free water in the egg gel, resulting in a reduction in Aw and an increase in storage lifetime. Additional polyhydric alcohols which may be used in combination with glycerol and propylene glycol include sorbitol, mannitol and the like.

Glycerol is well known and commercially available. Any glycerol having a purity sufficient for use in food products may be used in the present invention. The glycerol may, for example, be E422. The addition of glycerol to the egg gel has been found to increase the shelf life and prohibit the growth of bacteria, yeast and mould since the water activity of the final product is substantially lowered when compared to products that do not comprise glycerol. The glycerol is also believed to act as a solvent for the egg gel ingredients. Glycerol may also be a humectant and a softener. Suitable amounts of glycerol in the egg gel are 50-65 wt.%.

Propylene glycol is a humectant, retaining water and imparting a degree of product softness or tenderness. It may also serve as an antibacterial and/or antimycotic. In addition, it is believed to act as a solvent for the egg gel ingredients. The propylene glycol may be E1520. Suitable amounts of propylene glycol in the egg gel are 8-15 wt.%.

Additional humectants may be used either alone or in combination with glycerol and propylene glycol; these include sorbitol. Other antimycotic agents will be apparent to those skilled in the art and include benzoic acid, sodium benzoates, propionic acid, sodium and calcium propionate, sorbic acid, potassium and calcium sorbate, diethyl pyrocarbonate, menadione and sodium bisulfite.

The egg powder may be egg white powder, egg yolk powder or whole egg powder. Preferably the egg powder is whole egg powder. Avian eggs such as hen egg, duck egg or goose egg may be used. Preferably hen egg is used. Egg powder may be formed using any dehydration method known to a person skilled in the art, for example spray drying. Suitable amounts of egg powder in the egg gel are 10-20 wt.%.

In addition to the fat that is already present in the ingredients, additional fat is added to the egg gel. The term “fat” refers to the common usage of the term including glycerides that are solid and those that are liquid at room temperature, therefore the term “fat” also encompasses glyceride oils. Suitable amounts of fat in the egg gel are from 1 to 7 wt.%.

The fat may be any edible fat. The fat may be a triglyceride comprising C2 to C26 saturated or unsaturated fatty acids, preferably C6 to C24 saturated or unsaturated fatty acids, more preferably Ci2 to C20 saturated or unsaturated fatty acids. The fatty acids of the triglyceride may comprise monounsaturated, polyunsaturated and saturated free fatty acids and combinations thereof. Examples of unsaturated free fatty acids include myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid and docosahexaenoic acid. Examples of saturated free fatty acids include caprylic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, heneicosylic acid, behenic acid, lignoceric acid and cerotic acid.

The fat may comprise one or more vegetable fats. The fat may consist of, or consist essentially of, one or more vegetable fats. Vegetable fats include all plant, nut and seed oils. Examples of suitable vegetable fats which may be of use in the present invention include: agai oil, almond oil, babassu oil, beech oil, canola oil, cashew oil, coconut oil, colza oil, corn oil, cottonseed oil, grapefruit seed oil, grape seed oil, groundnut oil, hazelnut oil, hemp oil, hydrogenated palm kernel oil, lemon oil, macadamia oil, mustard oil, olive oil, orange oil, palm kernel oil, partially hydrogenated coconut oil, peanut oil, pecan oil, pine nut oil, pistachio oil, poppyseed oil, rapeseed oil, rice bran oil, safflower oil, sesame oil, soybean oil, sunflower oil, tucum oil, walnut oil, wheat germ oil or any fraction or combination thereof.

The fat may comprise one or more marine oils. Suitable marine oils include oils derived from the tissues of oily fish or crustaceans (e.g. krill). The fat may comprise one or more animal fats. Examples of suitable animal fats include pig fat (lard), duck fat, goose fat, tallow oil, and butter.

Emulsifiers are important ingredients in providing the emulsification and foaming properties typically associated with egg. Emulsifiers may be present in many different forms, such as alpha, alpha prime, beta and beta prime forms. In order to achieve the desired emulsification and foaming properties, it may be advantageous for the emulsifier to be in the alpha-crystalline form. The alpha-crystalline form is more flexible than the beta-crystalline form, thus emulsifiers in the alpha-crystalline form may be able to form more flexible and more protective films around the dispersed phase.

Non-alpha-tending emulsifiers are emulsifiers that may not form the alpha-crystalline form unless heated to above their melting point and/or may convert into another crystalline form from the alpha-crystalline form, impairing their emulsifying and/or foaming properties.

Alpha-tending co-emulsifiers are emulsifiers which are stable in the alpha-crystalline form and/or are ingredients which stabilise the alpha-crystalline form of the non-alpha-tending emulsifier. The use of an alpha-tending co-emulsifier may help to retain non-alpha-tending emulsifiers in the active alpha-crystalline phase. The specific combination of non-alpha-tending emulsifier and alpha-tending co-emulsifier in the egg gel of the present invention is believed to be important in producing the whippable and/or foamable properties observed in products comprising egg gel. Without being bound by theory, the addition of alpha-tending co-emulsifiers is believed to result in a flexible film of emulsifier at the fat interface between different phases, forming a stable emulsion and resulting in a stable foam after whipping.

The non-alpha-tending emulsifier may be any food grade emulsifier and may be natural or synthetic. Examples of emulsifiers used commercially include lecithins (E322) and esters of monoglycerides of fatty acids (E472a-E472f). Suitable amounts of non-alpha tending emulsifier in the egg gel are 2-10 wt.%.

Monoglycerides are polymorphic since they can exist in four crystalline forms: alpha, alpha prime, beta and beta prime. Powdered monoglyceride emulsifiers exist in the beta crystalline form, which is the most rigid and stable at low temperatures. When heated in the presence of water, the monoglyceride converts to the alpha-crystalline phase. This alpha-crystalline form is unstable and has a tendency to revert back to the beta-crystalline form. For this reason, monoglycerides are non-alpha-tending emulsifiers according to the present application.

The non-alpha-tending emulsifier used in the egg gel may comprise at least one mono-and/or di-glyceride. The non-alpha-tending emulsifier used in the egg gel may consist of, or consist essentially of, at least one mono- and/or di-glyceride. Suitable amounts of the at least one mono- and/or di-glyceride in the egg gel are 2-10 wt.%. The mono- and/or diglyceride may be a food grade E471 emulsifier.

The mono and/or di-glyceride may be a glyceride of one or two C2 to C26 saturated or unsaturated fatty acids, preferably C6 to C24 saturated or unsaturated fatty acids, more preferably Ci2 to C20 saturated or unsaturated fatty acids. The fatty acids of the mono-and/or di-glycerides may comprise monounsaturated, polyunsaturated and saturated free fatty acids and combinations thereof. Examples of unsaturated free fatty acids include myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid and docosahexaenoic acid. Examples of saturated free fatty acids include caprylic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, heneicosylic acid, behenic acid, lignoceric acid and cerotic acid.

The alpha-tending co-emulsifiers used in the egg gel may comprise glycerol monostearate, lactylated monoglycerides, acylated monoglycerides, propylene glycol monoesters, polyglycerol esters of one or more fatty acids, potassium stearate and sodium stearate. Suitable amounts of alpha-tending co-emulsifiers in the egg gel are 2-10 wt.%. The alpha-tending co-emulsifier may comprise at least one polyglycerol ester of one or more fatty acids and/or potassium stearate. Suitable amounts of at least one polyglycerol ester of one or more fatty acids in the egg gel are 2-10 wt.%. Suitable amounts of potassium stearate in the egg gel are 0.1-2 wt.%. The alpha-tending stabiliser may consist of, or consist essentially of, at least one polyglycerol ester of one or more fatty acids and/or potassium stearate. The weight ratio of the at least one mono-and/or di-glyceride to the at least one polyglycerol ester of one or more fatty acids may be 0.9:1 to 1.2:1, more preferably 1.1:1.

The polyglycerol ester of one or more fatty acids may comprise 2 to 10 glycerol repeat monomer units, preferably 2 to 4 glycerol repeat monomer units and/or may comprise one or more C2 to C26 saturated or unsaturated fatty acids, preferably C6 to C24 saturated or unsaturated fatty acids, more preferably Ci2 to C20 saturated or unsaturated fatty acids. The fatty acids of the polyglycerol ester of one or more fatty acids may comprise monounsaturated, polyunsaturated and saturated free fatty acids and combinations thereof. Examples of unsaturated free fatty acids include myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, a-Iinolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid and docosahexaenoic acid. Examples of saturated free fatty acids include caprylic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, heneicosylic acid, behenic acid, lignoceric acid and cerotic acid. The polyglycerol ester of one or more fatty acids may be food grade E475.

It has been found to be beneficial to use at least one mono- and/or di-glyceride as the non-alpha-tending emulsifier in combination with at least one polyglycerol ester of one or more fatty acids as the alpha-tending co-emulsifier. It has also been found to be particularly beneficial to include potassium stearate to the alpha-tending co-emulsifier . Without being bound by theory, it is believed that potassium stearate is important in retaining the mono- and/or di-glyceride in the alpha-crystalline form and helps to improve the dispersibility of the polyglycerol ester of one or more fatty acids in aqueous solutions, resulting in an egg gel which, when used in a food product, produces an egg-containing product which is whippable and/or foamable. A vegetable protein may optionally be added to the egg gel, which may be used to increase the protein content of the egg gel. The vegetable protein may be any known vegetable protein, including soy protein isolate, casein, caseinate salts, albumin, whey, pea isolate and/or lupin isolate. Also acceptable are cereal proteins such as wheat gluten and corn zein, and the common oilseed proteins. Soy flour is made by grinding soybeans into a fine powder and may be concentrated to provide at least 50 wt.% protein. Soy protein isolate (about 90 wt.% protein) is made from defatted soy flour which has had most of the nonprotein components, fats and carbohydrates removed. Suitable amounts of vegetable protein in the egg gel are 1-6 wt.%. The vegetable protein preferably comprises soy protein isolate. Suitable amounts of soy protein isolate in the egg gel are 1-6 wt.%. The vegetable protein may consist of, or consist essentially of, soy protein isolate.

The egg gel may optionally comprise a stabiliser. The stabilisers in the egg gel may be hydrocolloids. These may be natural or synthetic. Examples include guar gum, locust bean gum, acacia gum, caregeenan, methyl cellulose and HPMC. Suitable amounts of stabiliser in the egg gel are 0.05-1 wt.%. The stabiliser may comprise carrageenan. Suitable amounts of carrageenan are 0.05-1 wt.%. The stabiliser may consist of, or consist essentially of, carrageenan.

It has been found that the egg gel of this invention has an Aw below 0.6, preferably below 0.4. The egg gel may have an Aw from 0.2 to 0.5, preferably from 0.3 to 0.4. The egg gel of the invention has been found to be microbiologically stable under ambient temperature (e.g. from 10 °C to 40 °C, more typically from 15 °C to 35 °C, even more typically from 20 °C to 30 °C) and atmospheric pressure for a period of at least 1 month. Thus, in preferred embodiments, the egg gel of the present invention is stable under ambient temperature and atmospheric pressure for at least 1 month, more preferably at least 6 months, even more preferably at least 1 year. In particularly preferred embodiments, the egg gel of the present invention is stable when stored at 40 °C and at atmospheric pressure for at least 1 month, more preferably at least 6 months, even more preferably at least 1 year.

Reference to “microbiologically stable” above is intended to mean that the total concentration of bacteria, yeast and mould does not increase by more than 5 wt.% over the storage time, based on assessment of bacteria, yeast and mould concentration immediately before and after the storage period using the same assessment method.

The acid index is the mass of potassium hydroxide (mg) that is required to neutralise one gram of the egg gel. This is a measure of the number of free carboxylic acids in the compound, such as fatty acids. The egg gel of the invention was found to have an acid value within the range 1-5 mg KOH/g.

The saponification value is the mass of potassium hydroxide (mg) required to saponify one gram of fat and provides information about the average molecular weight of the fatty acid chains present in the egg gel. Long fatty acids have low saponification values because they have fewer carboxylic functional groups when compared to short chain fatty acids. The egg gel of the invention was found to have saponification values in the range 35-55 mg KOH/g.

It has been found that the particular combination of glycerol, propylene glycol, egg powder, fat, a non-alpha-tending emulsifier and an alpha-tending co-emulsifier in the egg gel food additive of the present invention, as described above, results in a low Aw and thus a long product shelf life, which is improved over that of fresh egg. This Aw may be in the range 0.2 to 0.5. These ingredients also result in the beneficial rheological and foamable and/or whippable properties observed in a food product comprising egg gel, which is improved over that observed in food products comprising conventional fresh egg substitutes such as egg powder. In particular, the combination of a non-alpha-tending emulsifier and an alpha-tending co-emulsifier is believed to result in the beneficial rheological and foamable and/or whippable properties observed in a food product comprising egg gel.

It has been found to be particularly beneficial to use at least one mono- and/or diglyceride as the non-alpha-tending emulsifier in combination with at least one polyglycerol ester of one or more fatty acids and potassium stearate as the alpha-tending co-emulsifier.

In one embodiment, the egg gel comprises glycerol, propylene glycol, egg powder, fat, at least one mono- and/or di-glyceride, at least one polyglycerol ester of one or more fatty acids and potassium stearate. In a further embodiment, the egg gel further comprises a vegetable protein and/or a stabiliser. In an embodiment, the egg gel comprises glycerol, propylene glycol, egg powder, fat, at least one mono- and/or di-glyceride, at least one polyglycerol ester of one or more fatty acids, potassium stearate, soy protein isolate and carrageenan.

In a further embodiment, the egg gel comprises 50-65 wt.% glycerol, 8-15 wt.% propylene glycol, 10-20 wt.% egg powder, 1-7 wt.% fat, 2-10 wt.% at least one mono-and/or di-glyceride, 2-10 wt.% at least one polyglycerol ester of one or more fatty acids and 0.1-2 wt.% potassium stearate. In a further embodiment, the egg gel further comprises 1-6 wt.% soy protein isolate and/or 0.05-1 wt.% carrageenan.

The invention further provides a process for producing an egg gel food additive comprising glycerol, propylene glycol, egg powder, fat, an alpha-tending co-emulsifier and a non-alpha-tending emulsifier, optionally further comprising a vegetable protein and/or a stabiliser, comprising the steps of: (i) mixing a minor portion of the glycerol and the alpha-tending co-emulsifier and heating the mixture to 70-90 °C; (ii) mixing the non-alpha-tending emulsifier, propylene glycol and fat and heating the mixture to 70-90 °C; (iii) combining the mixtures of (i) and (ii) and mixing at 70-90 °C before cooling to 40-60 °C; (iv) mixing the egg powder and a major portion of the glycerol (i.e. the remaining portion of glycerol to be added) and optionally the vegetable protein and/or the stabiliser and heating the mixture to 40-60 °C; and (v) combining the mixture from (iii) and (iv) at 40-60 °C. Additionally, the mixture of (iii) may be mixed at 70-90 °C for 5-30 min prior to cooling to 40-60 °C and the mixture of (iv) may be mixed at 40-60 °C for 5-30 min. The method may further comprise packaging the egg gel at 30-50 °C and/or the method may further comprise incorporating the egg gel into a food product.

In the method for making the egg gel, three reactors may be beneficially used, referred to as the first reactor, the second reactor and the third reactor. These reactors may be any reactor capable of performing the requisite steps. For example, the reactor may be a batch reactor, a tubular reactor such as a plug flow reactor or a continuous stirred tank reactor. These reactors may each comprise separate heat exchangers. The first reactor and second reactor must be capable of being heated to 70-90 °C. Heating may be performed by any suitable means known in the art. All three reactors must be capable of mixing the ingredients. Mixing may be performed by any suitable means known in the art.

The minor portion of the glycerol and the alpha-tending co-emulsifier are combined in the first reactor and heated to 70-90 °C with mixing. In the second reactor, the non-alpha-tending emulsifier, propylene glycol and fat are combined and the mixture heated 70-90 °C with mixing. Once the contents of the first reactor and the second reactor achieve the same temperature within the range 70-90 °C, the contents are combined by combining the mixture of the first reactor with that of the second reactor, for example by conveying the mixture of the first reactor to the second reactor via an outlet and inlet of the first and second reactors, respectively. Where, preferably, the content of the first reactor is added to that of the second, the addition is conducted gradually at a controlled rate. The combined contents are then mixed at 70-90 °C for 5-30 minutes before being cooled to 40-60 °C, preferably inside the second reactor.

In a third reactor the egg powder and a major portion of glycerol and optionally the vegetable protein and/or the stabiliser are combined and the mixture heated to 40-60 °C for 5-30 minutes with stirring. The mixture of the third reactor is then combined with that of the second reactor, preferably by adding the content of the third reactor to that of the second, whilst the second reactor is at 40-60 °C, and the resulting mixture stirred until the contents are well combined. Stirring may be performed for 5-30 minutes. The final egg gel may be packaged and/or used in a food product.

Alternatively, the minor portion of the glycerol and the alpha-tending co-emulsifier are combined in the first reactor and heated to 70-90 °C with mixing. In the second reactor, the non-alpha-tending emulsifier, propylene glycol and fat are combined and the mixture heated 70-90 °C with mixing. Once the contents of the first reactor and the second reactor achieve the same temperature within the range 70-90 °C, the contents are combined by adding the mixture of the second reactor into the first reactor. Where, preferably, the content of the second reactor is added to that of the first, the addition is conducted gradually at a controlled rate. The combined contents are then mixed at 70-90 °C for 5-30 minutes before being cooled to 40-60 °C, preferably inside the first reactor.

In a third reactor the egg powder and a major portion glycerol and optionally the vegetable protein and/or the stabiliser are combined and the mixture heated to 40-60 °C for 5-30 minutes with stirring. The mixture of the third reactor is then added to the first reactor while the first reactor is at 40-60 °C and the mixture stirred until the contents are well combined. Stirring may be performed for 5-30 minutes. The final egg gel may be packaged and/or incorporated into a food product.

The egg gel produced by this method may comprise any egg gel composition discussed above, with the alpha-tending co-emulsifier, the non-alpha-tending emulsifier, the vegetable protein and the stabiliser having been defined above. The alpha-tending coemulsifier may comprise potassium stearate and/or the non-alpha-tending emulsifier may comprise at least one mono- and/or di-glyceride and at least one polyglycerol ester of one or more fatty acids and/or the vegetable protein may comprise soy protein isolate and/or the stabiliser may comprise carrageenan. The fat may comprise vegetable fat. The alpha-tending co-emulsifier may consist of, or consist essentially of, potassium stearate and/or the non-alpha-tending emulsifier may consist of, or consist essentially of, at least one mono- and/or di-glyceride and at least one polyglycerol ester of one or more fatty acids and/or the vegetable protein may consist of, or consist essentially of, soy protein isolate and/or the stabiliser may consist of, or consist essentially of, carageenan. The minor portion of the glycerol may be 10-30 wt.% of the glycerol, preferably 20 wt.% of the glycerol. Mixing may be performed by any suitable means known in the art.

In yet a further aspect, the invention provides a food product comprising the egg gel as described above. These food products may be complete in flavour, texture and appearance as compared to products containing fresh egg, and may exhibit extended storage lifetime when compared to said fresh-egg-containing products.

It has surprisingly been found that a food product comprising the egg gel of the present invention is whippable and/or foamable and has very good foaming properties. These foaming properties greatly exceed those of food products comprising egg powder and more closely match food products made using fresh egg.

In some embodiments, the food products comprising the egg gel of the present invention are whippable and/or foamable and optionally the food products comprising the egg gel of the present invention are whipped and/or foamed. Preferably, the food products comprising the egg gel of the present invention are whipped and/or foamed. More preferably, this foam is stable.

The foaming qualities and coagulation properties of the various materials can be tested as follows: approximately 200 cm3 of an egg mass is beaten for 5 minutes and thereafter tested to determine the final volume and "drip" (amount of liquid settled in one hour). The drip test is a means of determining the stability of the foam. Thus, the more stable the foam, the less the drip. As defined in the present application, a stable foam exhibits no drip for at least 1 minute, preferably at least 5 minutes, more preferably 10 minutes and even more preferably 15 minutes.

It was found that the foaming qualities of the egg gel was substantially improved over a composition using egg powder and better simulated the foaming properties of fresh egg.

The egg gel of the present invention is suitable for replacing fresh egg and/or egg powder and/or other egg products in food products. In the replacement of egg powder with egg gel, approximately the same mass of egg gel may be used as would have been used of egg powder. For example, 1 g egg powder may be replaced with approximately 1 g of egg gel. In the replacement of fresh egg, approximately one quarter of the mass that would have been used of fresh egg may be replaced with egg gel, with water added to make up the remaining approximately three quarters of the mass. For example, 4 g fresh egg may be replaced with approximately 1 g of egg gel and 3 g water.

The invention also provides the use of the egg gel described above for improving the shelf life of an egg-containing food product, said egg-containing food product being described above. The invention further provides the use of egg gel for improving the shelf life of an egg-containing food product when the food product is whippable. The egg gel of the present invention has also been found to extend the storage life of an egg food product containing the egg gel when compared to an analogous product comprising fresh egg. Without being bound by theory, it is believed that the egg gel reduces the Aw of the food product, inhibiting microbial growth.

The present invention will now be described by reference to the appended figure and the below Examples, which are illustrative only.

Figure 1 is a schematic diagram illustrating the reactor set up and process for producing the egg gel in accordance with the process of the present invention.

As illustrated in Figure 1, a minor portion of the total glycerol (GL) and the alpha-tending co-emulsifier (ATCE) are fed into the first reactor (R1) in a feed stream (01). The glycerol (GL) and alpha-tending co-emulsifier (ATCE) feeds may be mixed prior to addition to the first reactor (R1) or added separately to the first reactor (R1) in any order. The mixed glycerol (GL) and the alpha-tending co-emulsifier (ATCE) may be combined using a stirrer (S1). The first reactor may be heated by a heater (H1), heating the mixed glycerol (GL) and the alpha-tending co-emulsifier (ATCE). The mixture in the first reactor (R1) is preferably heated by the heater (H1) to 70-90 °C.

The non-alpha-tending emulsifier (NATE), propylene glycol (PG) and fat (FAT) are fed into the second reactor (R2) in a feed stream (02). The non-alpha-tending emulsifier (NATE), propylene glycol (PG) and fat (FAT) feeds may be mixed prior to addition to the second reactor (R2) or added separately to the second reactor (R2) in any order. The mixed glycerol (GL) and the alpha-tending co-emulsifier (ATCE) may be combined using a stirrer (S2). The second reactor may be heated by a heater (H2), heating the mixed non-alpha-tending emulsifier (NATE), propylene glycol (PG) and fat (FAT). The mixture in the second reactor (R2) is preferably heated by the heater (H2) to 70-90 °C.

The egg powder (EP) and a major portion of the total glycerol (GL) and optionally the vegetable protein (VP) and/or the stabiliser (ST) are fed into the third reactor (R3) in a feed stream (03). The egg powder (EP) and glycerol (GL) and optionally the vegetable protein (VP) and/or the stabiliser (ST) may be mixed prior to addition to the third reactor (R3) or added separately to the third reactor (R3) in any order. The mixed egg powder (EP) and glycerol (GL) and optionally the vegetable protein (VP) and/or the stabiliser (ST) may be combined using a stirrer (S3).

Once the mixtures of the first reactor (R1) and second reactor (R2) have been heated, preferably to 70-90 °C, the mixture in the first reactor (R1) may be fed into the second reactor (R2) in a feed stream (04) and the mixture combined using a stirrer (S2). Once combined sufficiently, this mixture may be cooled to the temperature of the third reactor (R3).

The contents of the third reactor (R3) may be subsequently be added to the second reactor (R2) in a feed stream (05) and the mixture combined using a stirrer (S2).

The mixture in the second reactor (R2) may be removed via a stream (06) for further processing and/or packaging.

The example provided in Figure 1 is illustrative and demonstrates only one embodiment of the invention and should not be considered to limit the scope of the invention. For instance, in some configurations the mixture of the second reactor (R2) may be added to the third reactor (R3). Alternatively, the mixtures of the first and second reactors (R1 and R2) may be combined in the first reactor (R1) and subsequently the contents of the third reactor (R3) added to the first reactor (R1) or the mixture of the first reactor (R1) added to the third reactor (R3).

Examples

Example 1 - formation of an eoo pel

In this example, the following ingredients and quantities were used, as provided in Table 1 below.

Table 1

The egg gel was formed by the following process. In a first reactor, 62 kg of glycerol and 5 kg potassium stearate were combined and the mixture heated to 80 °C. In a second reactor, 25 kg mono- and/or di-glyceride, 60 kg propylene glycol, 23 kg polyglycerol ester of one or more fatty acids and 20 kg of fat were combined and the mixture heated to 80 °C. Once the materials in the first and second reactors came to 80 °C, the mixture of the first reactor was added to the second reactor. The resulting mixture was stirred at 80 °C for 10 min, following which it was cooled to 50 °C.

In a third reactor, 76 kg egg powder, 17 kg soy protein isolate, 1 kg carrageenan and 248 kg glycerol were combined and mixed for 10 min at ambient temperature. This mixture was then added to the second reactor with mixing. The resulting egg gel was packaged into 10 and/or 20 kg containers at 40 °C.

Example 2 - physical and chemical analysis of the egg gel

Analysis of the egg gel of Example 1 was performed after storage for 15 days. This analysis was performed by the Kimia Test Pharm Food and Health Lab (licensed by the Ministry of Health, Iran Standards and Industrial Research Organisation) using industry standard tests. These test results are shown in Table 2 below.

Table 2

Example 3-Aw of the egg gel

The Aw of the egg gel of Example 1 was determined using a LabMaster-aw machine manufactured by Novasina using standard techniques. The Aw was determined to be 0.3. This Aw value is sufficiently low so as to prevent the growth of microorganisms upon storage.

Example 4 - microbial analysis of the egg pel

Analysis of the egg gel of Example 1 was performed after storage for 15-30 days. This analysis was performed by the Kimia Test Pharm Food and Health Lab (licensed by the Ministry of Health, Iran) using industry standard tests. These test results are shown in

Table 3 below.

Table 3

Microbiological evaluation of the liquid egg gel of Example 1 disclosed a standard plate count, mould count and yeast count. The Commission Regulation (EC) No 2073/2005 states that for egg-containing products, salmonella should be absent in a 25 g sample during the shelf-life of the product. The test for salmonella under these conditions was negative; therefore, this sample meets these requirements. The low Aw of egg gel means that the growth of bacteria, yeast and mould is inhibited, as indicated in these tests. For this reason, egg gel is safe for long-term storage.

Example 5 - foaming ability of egg gel 50 g of the egg gel of Example 1, 200 g sugar and 100 mL of water were combined with a mixer for 5 minutes. A white foam was observed, which exhibited no drip for at least 1 minute.

Comparative Example 1 - foaming ability of egg powder 50 g of egg powder, 200 g sugar and 200 mL of water were combined with a mixer for 3 minutes. A white cream was formed and no foaming was observed.

The comparative example shows the advantage of egg gel over egg powder when used in a food composition. As egg powder does not contain emulsifiers, the product does not foam. Conversely, the egg gel of the present invention contains a particular combination

of emulsifiers which have been found to mimic the properties of fresh egg so as to rectify this deficiency in egg powder, resulting in a more acceptable egg substitute which has a longer storage lifetime than egg.

Claims

1. An egg gel food additive comprising glycerol, propylene glycol, egg powder, fat, a non-alpha-tending emulsifier and an alpha-tending co-emulsifier, wherein the egg gel has a water activity (Aw) below 0.6.

2. The egg gel according to Claim 1, wherein the non-alpha-tending emulsifier comprises at least one mono- and/or di-glyceride and the alpha-tending coemulsifier comprises at least one polyglycerol ester of one or more fatty acids and potassium stearate.

3. The egg gel according to Claim 1 or Claim 2, wherein the weight ratio of the at least one mono- and/or di-glyceride to the at least one polyglycerol ester of one or more fatty acids is 0.9:1 to 1.2:1.

4. The egg gel according to any one of Claims 1 to 3, wherein the egg gel further comprises a vegetable protein.

5. The egg gel according to any one of Claims 1 to 4, wherein the egg gel further comprises a stabiliser.

6. The egg gel according to any one of the previous claims, wherein the egg gel comprises 50-65 wt.% glycerol, 8-15 wt.% propylene glycol, 10-20 wt.% egg powder, 1-7 wt.% fat, 2-10 wt.% non-alpha-tending emulsifier, 2-10 wt.% alphatending co-emulsifier, 1-6 wt.% vegetable protein and/or 0.05-1 wt.% stabiliser.

7. The egg gel according to Claim 6, wherein the non-alpha-tending emulsifier comprises or consists essentially of mono- and/or di-glycerides, the alpha-tending co-emulsifier comprises or consists essentially of polyglycerol ester of one or more fatty acids and potassium stearate, the vegetable protein comprises or consists essentially of soy protein isolate, and wherein the stabiliser comprises or consists essentially of carrageenan.

8. The egg gel according to any one of the previous claims, wherein the egg gel has a water activity (Aw) from 0.2 to 0.5.

9. The egg gel according to Claims 2 to 8, wherein the mono and/or di-glyceride is a glyceride of one or two C2 to C26 saturated or unsaturated fatty acids.

10. The egg gel according to any one of Claims 2 to 9, wherein the mono- and/or diglyceride is a food grade E471 emulsifier.

11. The egg gel according to any one of Claims 2 to 10, wherein the polyglycerol ester of one or more fatty acids comprises 2 to 10 glycerol repeat monomer units.

12. The egg gel according to any one of Claims 2 to 11, wherein the polyglycerol ester of one or more fatty acids is food grade E475.

13. The egg gel according to any one of the preceding claims, wherein the fat is a vegetable fat.

14. The egg gel according to any one of the preceding claims, wherein the fat is a triglyceride comprising C2 to C26 saturated or unsaturated fatty acids.

15. The egg gel according to any one of the preceding claims, wherein the egg gel has an acid value of 1 to 5 KOH/g and/or a saponification value of 35 to 55 KOH/g.

16. A method for producing an egg gel food additive comprising glycerol, propylene glycol, egg powder, fat, a non-alpha-tending emulsifier, an alpha-tending coemulsifier, said method comprising the steps of: i. mixing a minor portion of the glycerol and the alpha-tending co-emulsifier and heating the mixture to 70-90 °C; ii. mixing the non-alpha-tending emulsifier, propylene glycol and fat and heating the mixture to 70-90 °C; iii. combining the mixtures of (i) and (ii) and mixing at 70-90 °C before cooling to 40-60 °C; iv. mixing the egg powder and a major portion of the glycerol and heating the mixture to 40-60 °C; and v. combining the mixture from (iii) and (iv) at 40-60 °C.

17. The method of Claim 16 where the egg gel food additive further comprises vegetable protein and/or a stabiliser, wherein the vegetable protein and/or the stabiliser are mixed with the egg powder in step iv.

18. The method of Claim 16 or 17, wherein the minor portion of the glycerol is 10-30 wt.% of the glycerol.

19. The method of any one of Claims 16 to 18, wherein the mixture of (iii) is mixed at 70-90 °C for 5-30 min prior to cooling to 40-60 °C and wherein the mixture of (iv) is mixed at 40-60 °C for 5-30 min.

20. The method of any one of Claims 16 to 19, wherein the egg gel comprises at least one mono- and/or di-glyceride, the alpha-tending co-emulsifier comprises at least one polyglycerol ester of one or more fatty acids and potassium stearate, the vegetable protein comprises soy protein isolate, and the stabiliser comprises carrageenan.

21. The method of any one of any one of Claims 16 to 20, wherein the method further comprises packaging the egg gel at 30-50 °C.

22. The method of any one of any one of Claims 16 to 21, wherein the method further comprises incorporating the egg gel in a food product.

23. A food product comprising an egg gel, wherein the egg gel has the composition of any of Claims 1 to 15.

24. A food product according to Claim 23, wherein the food product is whippable and/or foamable.

25. Use of an egg gel for improving the shelf life of an egg containing food product, wherein the egg gel is as defined in any one of Claims 1 to 15 and wherein the food product is whippable and/or foamable.