NO771363L - LIPOPROTEIN EMULSIONS FOR USE IN FOODS, PROCEDURES FOR THEIR PREPARATION AND FOODS CONTAINING SUCH EMULSIONS - Google Patents

Description

The invention relates to methods of production

of lipoprotein systems intended for use in baked goods and other foodstuffs. The invention also relates to the composition of egg yolk substitutes that are used alone or combined with egg white or other types of heat-coagulable proteins as a substitute for all or part of the eggs used in the baked goods or food.

Eggs are a basic ingredient in cakes and other baked goods and fulfill specific functions while increasing their quality. The functions of eggs and egg yolks that are important in cake batter include: emulsifying ability, raising effect, protein-binding effect for maintaining the cake's volume and cell structure, softening effect, moisturizing effect that maintains freshness, nutritional value from proteins and overall improvement of eating quality.

Although eggs are readily available, their price limits their use in baking. A cheap substitute that would have the functions of the egg yolk would be of great value.

About a dozen egg yolk substitutes are now available

in the trade (USA) and is analyzed. The present applicants' investigations show that they lack the desired functional properties for use in cake products and the like. The cake samples made with marketed egg yolk substitutes produced cakes with varying degrees of low volume, coarse texture, uneven cell structure, brittleness and useless taste.

It is therefore an aim of the invention to provide an improved composition and method for the production of lipoprotein emulsion systems which have the desired properties for replacing part or all of the amount of egg yolks in cakes and other foodstuffs.

One aspect of the invention is to provide methods that improve the solubility and properties of soy protein fractions as egg yolk substitutes.

Thus, as a side of the invention, egg yolk substitutes are provided which consist of an emulsion of a water-soluble protein component, vegetable oil, lecithin and other selected ingredients.

According to the invention, methods are provided for the production of egg yolk substitute in liquid or dried form for use in cakes and other foodstuffs.

Another aspect of the invention consists in egg yolk substitutes to be used in combination with egg white or other temperature-coagulable proteins as a substitute for part of the eggs used in cakes and other foodstuffs.

According to the invention, it is used liquid

or dried fat-protein emulsions to replace egg yolks in cakes, doughnuts, buns, puddings and similar foods.

Another aim of the invention is to provide stable lipoprotein emulsions which can be used as a substitute for the fat globule membrane in whole milk for use in the production of beverages with a high protein content.

Another purpose of the invention is to produce lipoprotein emulsions that can be used for special dietary purposes

where the content of the food in protein, unsaturated fat and cholesterol

is of importance.

Yet another object of the invention is to provide

an easily digestible food system that can provide good protein and fat digestion in people with digestive difficulties,

e.g. peptic ulcer, liver disease or gallbladder disease.

Other features and advantages of the invention will be understood from the following description in connection with the attached drawings, where: fig. 1 schematically reproduces the method for producing lipoprotein emulsions from a protein solution,

fig. 2 schematically shows the procedure for

in

position of lipoprotein emulsions with dry protein that have high solubility and dissolve easily in water,

fig. 3 schematically shows the procedure for

the procedure for producing fat-protein emulsions with a sparingly soluble protein,

fig. k schematically reproduces a modified method from fig. 3 for the production of lipb protein emulsions from protein that is difficult to dissolve.

The functional properties of egg yolk in cakes

and other foods and which include emulsifying ability, protein-binding ability, tenderizing ability, moisturizing effect etc. can be attributed to the properties of lipoproteins found in the egg yolk. The lipoproteins in the yolk, lipovitellin and lipovitellin, are made up of the proteins vitellin and vitellin with the phospholipids lecithin (phosphotidylcholine) and cephalin (phosphotidylethanolamine). The proteins vitellin and vitellin are insoluble except at alkaline pH

and only part of the phospholipids, lecithin and cephalin are in equilibrium binding with these proteins.

There is a remarkable similarity between the natural lipoproteins in egg yolk and lipoprotein emulsion systems produced according to the invention. Soy protein isolates or other protein sources used in the preparation of egg-yolk emulsions as emulsions become soluble at alkaline pH. This gives a strong net electronegative charge on the protein molecules. The electronegatively charged protein molecules then form complexes or groups with strong electropositive groups in lecithin (phosphotidylcholine) and cephalin (phosphotidylethanolamine) found in the soybean lecithin used in the emulsion system. Fat protein conjugates (-complexes) that are formed in this way

are hydrophilic (protein) hydrophobic (fat) dipoles that reduce the surface tension between the oil and water phases of the emulsion system and form lipid globule membranes that serve as a protective sescolloid for stabilizing the emulsion and provide the functional properties that are characteristic of natural lipoproteins in egg yolk or the fat globule membrane in milk.

Lipoproteins produced according to the invention can therefore be used as a substitute for egg yolk in cakes and other foodstuffs. These emulsions can also be used for the production of liquid or dried protein drink preparations that have the same physical stability as whole milk.

Present lipoprotein emulsions provide a significant improvement in quality and functional properties for egg yolk substitutes to be used in cakes and other baked goods. A method has been developed for the production of lipoprotein emulsions which have the functional properties of egg yolk. The emulsions are made from proteins from soybeans or whey as well as other cheap food ingredients. The emulsions have a low cholesterol content, which is an advantage for people who want to reduce the absorption of cholesterol. The lipoprotein emulsions can be prepared in liquid, frozen or solid dry form for use

in different foods. They can also be mixed with whole eggs, egg whites or other temperature-coagulable proteins for use as an egg substitute.

The lipoprotein system consists of protein, edible oil, lecithin, emulsifiers and dyes which are mixed and homogenised into a stable emulsion. When the lipoprotein emulsion is produced in dry form by spray drying or freeze drying, sucrose or other soluble carbohydrates such as maltodextrins or solids from corn syrup are added to the emulsion before drying to prevent protein denaturation during drying, to provide emulsion stability and contribute to the solubilization of the dry product . The composition of the emulsion, including the content of protein, cooking oil and lecithin, can be varied to adapt the properties to those desired in different foodstuffs.

The applicants have discovered that the solubility and the gel or film-forming property of the protein component is particularly important for the production of egg yolk substitutes to be used in cakes. The binding ability of the protein is also important in cakes where such binding force is necessary to maintain the cake volume, cell structure and consistency. Inexpensive and readily available proteins rated as protein sources are soy protein isolates and whey proteins. Examples of different proteins that have been taken into account appear in Table I.

Good results with regard to cake volume, particle structure and consistency were achieved with a fat protein-egg-yolk batter made from soy protein isolate "Supro 700", which has good solubility and film-damaging properties. Good results have also been achieved with other soy protein isolates when in soluble liquid form or when treated to improve solubility as described later.

Different types of fats and cooking oils were evaluated for use in egg yolk substitutes. A good cake appearance and consistency was achieved with soybean oil, which is easily available on the market. However, other "vegetable" oils can also be used and they give better results than solid fats such as hydrogenated lard and lard which were also tested.

Various lecithin products were tried as substitutes for phospholipids, namely lecithin and cephalin which are found in natural egg yolk and provide emulsifying properties which are essential for good cake batter. Commercially available soybean lecithin, A.E. Staley's "Sta-Sol" containing approx. 63% phosphatides and approx. 37$ soybean oil produced the desired result.

Beta-carotene was chosen for coloring the emulsions because it is a natural product and it is cheaper than the other natural pigments in eggs such as xanthophyll and zeaxanthin.

Disodium phosphate and surfactants including sorbitan monostearate, polysorbate 60 and sodium stearoyl-2-lactylate were added to improve the solubilization of the protein and provide emulsifying properties.

When using protein solutions such as liquid soy protein isolate of the "Supro 620" type, the pH is adjusted if necessary, the other ingredients are added and the mixture is emulsified.

As mentioned, procedures have been developed to improve the solubility and functional properties of dried soy protein isolates to be used in lipoprotein emulsions.

When using dried protein products that are difficult to dissolve, the desired solubility is achieved by setting the pH of the protein dispersion to alkaline pH, heating the solution to between 65 and 82°C and homogenizing. The effect of alkaline pH on the solubility of soy protein is well known. The combined effect of alkaline pH plus heating and homogenization for breaking up the protein aggregates is particularly effective for dissolving soy & protein isolates.

Investigations into the protein solubility at different pH values showed that the desired results could be achieved by setting the pH of the protein dispersion to 9.5 to 10.0. Setting the protein dispersion to pH 9-5 improves the emulsifying ability and the functional properties of protein to be used in egg yolk substitutes. When the protein dispersion is adjusted to pH 9 to 5, the final pH in the lipoprotein emulsion is pH 8.4 to 8.8, which is about the same as the pH in technically manufactured dried whole egg products.

The effect of pH, heating and homogenization on the solubility of soy protein isolates appears in Table II. The solubility of soy protein isolate "Supro 620" was increased from 27.9$ to 96.6$ by adjusting to pH 9.5, heating to 82°C

and homogenize. The effect of pH on the properties of egg yolk tatting of formula V-A (Table v) using "Supro 710" soy protein isolate is shown in Table III. The specific cake volume and the quality assessment were improved when the pH of the protein solutions was increased from 7 to 10.

The effect of increased protein solubility on the functional properties of egg yolk substitutes was investigated in cake baking experiments where 50$ of the natural egg yolk in the dough was replaced with a fat protein emulsion. The results of these investigations are shown in table IV. Cake volume as well as appearance, consistency, graininess, tenderness and eating quality were improved by treating "Supro 620" or "Supro 710" soy protein isolates by improving their solubility in the emulsion system.

Illustrations of methods that can be used

for the production of lipoprotein emulsions with good properties for use in cakes and other baked goods can be found in fig. 1 to 4.

Fig. 1 shows the method used when using a protein solution such as e.g. liquid soy protein isolate of the type "Supro 620".

When using soluble dried protein such as "Bupro 700" or Protolac, Lactalbumin Phosphate, for the production of egg yolk substitutes, effective results are obtained by the method shown in fig. 2. The protein is dissolved by rapid mixing in water at room temperature, containing disodium phosphate and surfactants such as sodium monostearate, polysorbate 60 and sodium stearyl-2-lactylate. Soybean oil, lecithin, beta-carotene and sucrose or other soluble carbohydrates are added during thorough mixing. The mixture is emulsified through a Gaulin homogenizer, which during the first pass is set at 175 kg/cm and in the second step at 35 kg/cm. The liquid emulsion can be used as a substitute for egg yolk or can be spray-dried or freeze-dried into a dry product.

Fig. 3 illustrates a process that gives good results with proteins that are difficult to solubilize. A liquid mixture was prepared with the following recipe for the method in fig. 3"

Lipoprotein Egg Yolk Substitute Recipe

Approach.

1. The first four ingredients (3 emulsifiers and disodium hydrogen phosphate or polyphosphates) were mixed in hot water (approx. 45°C) in a 200 liter boiler with a heating jacket. 2. Long-stem soy protein was added to the water, which was stirred relatively slowly with a large-bladed stirrer. The mixing speed was approx. 200 - 300 with a stirrer with approx. 25 cm diameter wooden blade propeller, The dry soy protein isolate was easily dispersed without clumping. Thorough mixing with good turbulence was achieved with the help of the large stirring blades. 3"pH adjusted to 9.5 with sodium hydroxide solution. 4. The mixture was slowly heated with continued stirring. The contents were heated from 32 - 82°C during 39 minutes with a vapor pressure of approx. 1/0.35 kg/cm 2 for steam in/steam out, respectively. 5. The mixture was homogenized in a positive pump "Crepaco 2R" for feeding two Gaulin homogenizers in series. Both homogenizers operated in the first/second stage with a pressure of approx. 175/35 kg/cm 2. 6. Oil, lecithin and beta-carotene were mixed together and added to the mixture while stirring. Sugar was stirred in. 7. The mixture was homogenized again at the same pressure as during step 5, but only in a homogenizer. 8. The emulsion was cooled to room temperature. It can be used as such in liquid form or can be spray- or freeze-dried to a substantially dry product. 9. Spray drying was carried out in a gas-fired drying tower with a diameter of 1.8 m and a height of 10.5 m. 10. The moisture content of the final product was kept between 2-8$ and preferably 4-5$.

The procedure shown in fig. 4 differs from the above in that the first homogenization step for solubilization of the protein is omitted and the protein solubilization and emulsification are carried out simultaneously. By using the method in fig. 4, the protein is dispersed and the pH adjusted in the same way as in process 3» Soybean oil, lecithin, beta-carotene and sucrose or other carbohydrate are added and the entire mixture is homogenized twice through a Gaulin homogenizer where the first stage is set to 175 kg/cm 2 and second steps of 35 kg/cm 2. After cooling, the emulsified egg yolk substitute can be used in liquid form or dried in the same way as described above under method 3"

Both process 3 and 4 give good results, but method 3 is preferred as it is more effective with proteins that are difficult to dissolve.

Process sizes and preferred conditions for the production of lipoprotein emulsions

(l) pH adjustment

(2) temperature

(3) homogenization

In Gaulin homogenizer:

Other conditions can be used in a colloid mill or similar equipment.

(4) emulsification, process I, II and III

In Gaulin homogenizer:

Experiments with the best surface appearance and other trials were carried out to find the best combinations of the main ingredients including protein, soybean oil and lecithin as necessary for the composition of egg yolk substitutes in cakes and other baked goods. These studies showed that the composition can be varied to fulfill certain functional properties for special purposes. Examples of lipoprotein emulsions that give varying properties in cakes and other foodstuffs appear in table V:

Experiments with the above recipes for egg-yolk tatting have shown that the following ingredients are not absolutely necessary when the pH of the protein solution is adjusted to pH 9.0 to 10.0: disodium phosphate, sodium stearoyl-2-lactylate, polysorbate 60 and sorbitan monostearate. However, the consistency of certain cake products is improved when these ingredients are added individually or in various combinations to the basic recipe found in the preferred embodiments.

Substitutes for whole egg dry matter were produced

by mixing approx. 70 parts by weight of dried egg yolk substitute, formula V-A, V-B or V-C with approx. 30 parts by weight of dried egg white, which is approximately the ratio of yolk/white in dried whole eggs,

or an equivalent amount of temperature coagulable protein such as Borden<1>'s "protolac" lactalbumin phosphate. These mixtures of egg yolk substitute and egg white were used to replace approx.

50$ whole egg dry matter that was used for cake tin.

Egg yolk substitute V-A gives cakes with a fine internal pore structure and soft consistency with a specific volume (cm/g) as large as the control sample. Substitute V-B containing no added oil other than the oil in the lecithin ingredient gave a uniform grain or pore structure more open than that of the control sample and a firm consistency that was less mushy with Substitute V-A

or the control sample, but with excellent cake volume. Substitute V-C containing a smaller amount of added soybean oil gave

very usable pore structure and the cake had a softer consistency than cakes with the substitute V-B and better volume than V-A. Formula V-C

was chosen as a general egg yolk substitute for use in cakes, V-C is useful when softness and moistness in the mouth are of greatest importance and V-B can be used when cake volume and firmness are of greatest importance.

Formula V-D has been developed as an egg yolk substitute for use in combination with whole egg dry matter to produce yolk-fortified whole eggs to be used in cake recipes that require added egg yolk. A mixture of approx. 3^.6 parts by weight emulsion V-D with approx. 61.4 parts by weight whole egg dry matter was evaluated with regard to replacing a marketed yolk-enhanced whole egg dry product in small chocolate cookies. The test cakes had very good volume, pore structure, consistency and eating quality and were of the same quality as comparison cakes made with marketed yolk-enhanced whole egg dry matter products.

The following examples illustrate the invention: Example I Mold cake A

As an example of the application of the invention, cakes were made with egg yolk substitute formula V-C, which replaced 50% of the egg yolk solids, and the results were compared with control cakes. The cakes contained the following ingredients:

The cakes were prepared as follows: All the dry ingredients except the yeast were mixed in a Hobart mixer model C100 (Hobart Manufacturing Co., Troy, Ohio) at the lowest speed for 2 minutes with a four-blade stirrer. Half the water was added and mixed at highest speed for 3 minutes. The rest of the water and yeast were added and mixed for 2 minutes at the lowest speed. Bake on a tray for 12 minutes at 205°C. This procedure was used for both the test cakes and the control cakes.

Results:

The cakes were judged after 24 days and 5 days after baking with regard to volume and general cake quality. The test cakes were judged to be equivalent to the control cakes after 24 hours and after 5 days of storage. The cake quality rating for these cakes after 24 hours was as follows:

Example II Mold cake B

As another example of the use of the invention, shaped cakes were produced by replacing 50$ of the whole egg dry substance with a combination of egg yolk substitute formula V-C and temperature-coagulable whey protein concentrate which was used instead of egg white. The ingredients used in the control sample and test cakes were as follows:

protein concentrate containing 57$ protein.

The cakes were prepared as described in Example I.

All the dry substances except the yeast were mixed in a Hobart mixer model C100 at low speed for 2 minutes with a four-blade stirrer. Half of the water was added and mixed at highest speed for 3 minutes. The rest of the water and yeast were added and mixed for 2 minutes at the lowest speed. The cakes were baked on trays for 12 minutes at 205°C. This was done for both test cakes and control cakes.

Results;

The cakes were judged after 24 hours and 5 days with regard to volume and other cake properties. The test cakes were considered as good as the control cakes after 24 hours and after 5 days of storage. The assessment figures for the test and control cakes after 24 hours were as follows:

Example III. Layer cake.

As a third example of the invention in practice, layer cakes with egg yolk substitute formula V-C were produced as a substitute for 50$ of egg yolk dry matter and the result was compared with control cakes. The ingredients were the following:

Approach:

The cakes were made in the following manner: All dry ingredients except the yeast were mixed in a Hobart mixer model C100 which was run at the lowest speed for 2 minutes. The fat was added and 2/3 of the water at the lowest stirring speed with a four-blade stirrer. One mixed for 2 minutes at the highest speed and the rest of the water was mixed in during 2 minutes at the lowest speed. 368 g of dough was weighed out in a 20 cm round cake form. It was baked for 25 minutes at 190°C.

The same procedure was used for both the test cake and the comparison cakes.

Results:

The cakes were judged after 24 hours and 5 days with regard to volume and overall quality. The test cake was judged to be about as good as the control sample after 24 hours and after 5

- days. The assessment after 24 hours was as follows:

Example IV. Chocolate cake cup.

Fortified whole egg dry matter containing added egg yolk is a common ingredient in many cake recipes.

As a fourth example of the execution in practice, chocolate cake cups were made with yolk-enhanced whole-egg dry matter, where the control cakes and experimental cakes were baked with whole-egg dry matter reinforced with egg yolk substitute formula V-D. The following ingredients were used in the dough for baking the comparison and test cakes:

Approach;

The cakes were prepared as follows: Mix the dry ingredients, add the fat and 2/3 of the water, mix for 1 minute at lowest speed and 2 minutes at medium speed in a C100 Hobart mixer with four-blade stirrers. Baking powder, soda and the rest of the water were added and mixed for 2 minutes at the lowest speed in the mixer. Portions of 30 g were weighed out in greased cup molds and these were baked for 14 minutes at 193°C. Results: The cakes were judged after 2k hours and 5 days with regard to volume and eating quality, the test cakes had just as good volume, appearance, internal consistency and taste as the control cakes. Details regarding the quality assessment were:

Example V. Donuts.

As another example of the invention's execution in practice, two different groups of donuts were made, where the control donut contained egg yolk solids and experimental donuts containing added egg yolk substitute (V-C) for partial replacement of the egg yolk. The donuts contained the following substances:

Approach:

The dough was made by mixing the ingredients in a bowl for 1 minute at lowest speed on a Hobart mixer C100 with a dough hook, mixing for 2 minutes at medium speed. The mixture was set aside for 10 minutes for equilibration. A DCA Lincoln lard pot was used for lard frying the rings. They were fried for 60 seconds on each side at 193°C. Results;

Addition of 2$ egg yolk replacer significantly improved the volume, overall quality and shelf life of the doughnuts. After 8 days of storage, the test donuts were clearly better with respect to freshness, softness and overall eating quality. A quality comparison follows below:

Example VI. Bowls.

As another example of the invention, ordinary buns were made with lipoprotein emulsion (formula V-C) to replace $100 of the egg yolk in the bun recipe.

The bowls were made with the following contents:

Approach:

The bowls were made in the following way: The dry ingredients were mixed, the fat and water added, mixed for 5 seconds at lowest speed in Hobart mixer C100, the bowl scraped and further mixed for 5 seconds at low speed.

50 g portions were weighed out in greased cup molds and these were baked for 18 minutes at 218°C,

Results:

The experimental and control bowls had the same volume. The test balls had the same appearance, consistency and eating quality as the control balls.

Example VII. Pudding.

As yet another example according to the invention, a pudding was made with egg yolk substitute with formula V-A to replace $100 of egg yolk solids in the recipe. For this purpose, egg yolk substitute V-A was made with sodium protolac, which is a whey protein concentrate supplied by Industrial Food Products, Borden, Inc. instead of soy protein isolate as a protein ingredient, and the egg yolk substitute was prepared according to process I, fig. 1. The ingredients used were the following:

Approach:

The pudding was made as follows: The dry ingredients were mixed in a bowl, water added and this mixed at high speed to dissolve the ingredients. The bun mixture was poured into 170 g molds which were placed in a water bath (2y cm deep) and baked at 177°C for h5 minutes.

Results:

The test pudding hardened in the same way as the control sample with whole eggs. The taste and consistency of the test pudding with egg yolk substitute was considered as good as the comparison sample.

Example VIII. Salad dressing.

As an example of yet another application of the invention, a creamy salad dressing was produced with lipoprotein emulsion formula V-A plus egg white in a natural yolk/white ratio, to replace whole eggs. The salad dressing was considered as good as a comparison sample with whole egg dry matter. The recipe was:

Approach;

The salad dressing was made as follows: The dry ingredients were mixed together, vinegar and eggs were added (in the test recipe, egg white solids are mixed with liquid lipoprotein emulsion), oil was slowly added and the whole thing was beaten in an electric mixer until all the oil had been added.

Results:

Both the test and control dressings were considered satisfactory in terms of consistency and smell and taste qualities. The test dressing was somewhat thicker than the comparison dressing, which is an advantage for this product. However, the consistency could be made thinner by reducing the amount of lipoprotein emulsion and egg white solids.

Example IX, Beverage with a high protein content.

Drinks with a high protein content are an example of another type of food that can be made with lipoprotein systems as described in the invention. Soya protein isolates or a combination of these and whey protein concentrates can be used for the production of physically stable drinks that have approximately the same protein and fat content as whole milk. Typical examples are:

Approach; 1. Disodium phosphate, sorbitan monostearate, polysorbate 60 and sodium stearoyl-2-lactylate were added to water at approx. 50°C and dispersed well in an electric stirrer.

2i Soy protein isolate and whey protein concentrate were added and homogenized under pressure settings on

175 kg/cm 2 in the first pass and 35 kg/cm 2 in the second pass.

3. Sugar, carrageenan and cocoa powder were added

to the homogenized protein solution. The mixture was pasteurized at 72°C for 40 minutes. 4. Soya oil, lecithin and flavorings were added and mixed thoroughly. Homogenization was done again as under point 2.

5»It was cooled to 5°C and stored in bottles, stored in a refrigerator.

Results:

Drinks with a high protein content of the aforementioned type had approximately the same protein and fat content as milk. Taste and consistency were rated as good as chocolate milk.

The invention has been demonstrated in practice as a full or partial replacement in cakes, buns, doughnuts, puddings and the like and in salad dressings, protein-containing drinks and other foodstuffs. The lipoprotein products according to the invention have nutritional qualities that are suitable for special dietary purposes. The lipo-protein has a high protein content, contains unsaturated fat and has a low cholesterol content, which can be an advantage when you want to reduce your intake of calories, fats and cholesterol. The digestibility of the fat components is increased by the highly emulsified state of the lipoprotein system and this property can be useful in regulating certain digestive disorders such as biliary colic.

Claims (1)

Process for the production of lipoprotein emulsions for use in foodstuffs, characterized by dissolving disodium phosphate, sorbitan monostearate, polysorbate 60 and sodium stearoyl-2-lactylate in warm water, dispersing the soy protein isolate in the water while stirring, setting the pH of the dispersion to approx. 9.0 to 10.0 upon addition of alkali, the pH-adjusted protein dispersion is heated to approx. 55 to 95 oC with stirring, homogenize the heated dispersion twice through homogenizer under a first homogenization pressure of 175 kg/cm 2 and a second stage pressure of 35 kg/cm 2 , add oil, lecithin, flavorings, colorants and soluble carbohydrate to the protein solution while stirring, emulsifies the entire mixture in a homogenizer under a first homogenization pressure of 175 kg/cm 2 and a second homogenization pressure of 35 kg/cm<2> and cools the emulsion.