CZ300210B6 - Method of removing sugar from egg white and gumbo - Google Patents

Abstract

When removing sugar from egg white and gumbo the present of glucose in a liquid egg white or a homogenized egg material is lowered to a desired level by batch or continuous fermentation process thereof under generation of ethanol, carbon dioxide and optionally other metabolic products after addition of a sufficient amount of lactic yeasts biomass of the Kluyveromyces or Fabosporana strains at a temperature ranging from 5 to 45 degC and pH value in the range of 4 to 8.

Description

Technical field

The invention relates to the removal of glucose from egg melange and egg white prior to drying and pastoral care in order to eliminate the formation of undesirable brown coloration of the end product and to extend its shelf life.

The current state of these niches

Dried egg white is an important raw material of the food industry. The liquid form of egg white contains approximately 4g / ^l glucose. The presence of glucose in the egg white causes it to turn brown during drying and storage of the dried product as a result of a Mailliard reaction in which reducing sugars react with amino groups of amino acids, free or bound in peptides and proteins, to produce a yellow or brown color. The brown color of dried egg white is considered to be a significant defect of this product and significantly reduces its marketability. The presence of glucose in egg products during drying also leads to their reduced solubility. Moreover, the elimination of glucose from dried egg mass and egg white increases the resistance of these products to the activity of microorganisms and thus increases their shelf life. For this reason, glucose is usually removed from egg mass or egg white prior to drying and pastoral care.

After removal of the glucose, egg egg and egg white are usually spray dried. Another way is to dry the trays and pans into flakes or granules.

The presence of undesirable microorganisms, in particular of hazardous Salmonella bacteria in the final product, is mostly eliminated by pastoral work, which is usually carried out after drying of the egg white in special heated chambers. Pastoral care must be carried out in a gentle manner to avoid coagulation and denaturation of proteins and consequently impairing the functional properties of the protein.

Industrially, two types of processes are used to remove glucose from liquid egg mass or egg white:

- fermentation process using appropriate micro-organisms, bacteria or yeasts, which break down glucose into suitable metabolic products

- Decomposition of glucose with the aid of the added glucose oxidase enzyme (GOD. β-D-glucose: oxygen I-oxidoreductase, EC 1.1.3.4) or micro-organisms producing this enzyme, to Dglucono-1,5-lactone and hydrogen peroxide according to the equation:

4l)

BD-glucose + O ₂ <-► D-glucono-1,5-lactone »IECl ·

Femientiation with naturally present microorganisms is a traditional method of reducing glucose content and hence improving the quality and shelf life of dried egg white. In 1943 successful attempts were made to stabilize the whole dried egg mass by its previous liquid fermentation by some added bacterial strains, but it was not clear from the results whether the final product quality was achieved by glucose fermentation or acidification of the mass by acidic bacterial fermentation products. (Stewart, Best and Lowe. Proc. Inst. Food Tech. 1943, 77). Soon thereafter, a fermentation procedure for removing glucose from liquid egg mass by added yeast was published by other authors (J.S.CT, 1944, 63, 234) without substantially altering the pH of the product. This procedure led to an increase in the durability of the subsequently dried egg mass, but the disadvantage was the apparent foreign flavor. The authors of this publication later received a patent GB 606 292 (1948) for an altered fermentation process for removing glucose from egg white using yeast biomass. This British patent describes a process for saccharification of egg white by fermentation

Bo brewer's yeast (Saccharomyces apiculatus) or baker's yeast (Saccharomyces eerevisiae) at temperatures above 45 ° C, but below the denaturation or coagulation temperature of the egg white. A temperature in the range of 45-50 ° C and a yeast biomass concentration of approximately 1% (wet weight of yeast relative to the wet weight of egg white) are recommended as the most suitable. The fermentation process is terminated after the glucose concentration has fallen to the desired level, most often after 20 to 30 minutes. After fermentation, the egg white with yeast biomass is immediately dried.

The use of high fermentation temperatures above 45 ° C has the advantage that the growth and multiplication of pathogenic bacteria is reliably suppressed. Yeast propagation is already at these temperatures. also suppressed, but κι fermentaee glucose continues at an elevated rate for a sufficiently long time to eliminate enough of it from egg white. The glucose concentration can be reduced to about 1/4 of the initial value by this procedure. The fermentation can be carried out in a batch or continuous manner. The egg white treated in this way does not brown during cooking and has a longer shelf life.

A method for saccharifying egg melange by rapid continuous heterogeneous fermentation using immobilized yeast has also been described (May SW. Padgette SK.

Indian authors have described the use of baker's yeast also mobilized in calcium alginate to remove glucose from egg melange in a batch manner. With a sufficiently high dose of immobilized yeast, almost complete glucose removal was achieved within 60 minutes. The preparation with mobilized bvl cells was used 30 times in succession without significant decrease in activity (DSouza, SF. Godbole, $. S. Went from glucose from egg prior to administration by fermentation with immobilized yeast cells. 21 1-212).

Egyptian authors described and compared the process of saccharification of egg white using baker's yeast (Saccharomyces eerevisiae) in the presence of 0.2% yeast extract (pH 6.5 to 7.5, temperature 32 ° C), Streptocoecus lactis in the presence of 0.2% yeast extract (pH 6.0, temperature 30 ° C) or Aerobacter aerogenes (pH 7.0, temperature 37 ° C). Significant adverse sensory and end product changes were observed with Streptocoecus lactis. When Aerohacler aerogenes were used, a sufficient reduction in glucose concentration was achieved after 3-4 hours of fermentation. when using baker's yeast after 9 hours. The fermentation time required to sufficiently reduce glucose concentration is dependent upon the initial concentration of the microorganism used (Shehab, SK. Darwish, NM. Sadek. MA. Depletion of glucose in Egyptian egg white before dehydration. ).

Russian authors used Acetobacter .xylinum for fermentation desugarization of egg whites,

4o Streptocoecus / actis. Propionibacterium sherwanii. Ex. Petersonia and coca-forming propionic acid. Optimal conditions for de-saccharification were found for individual bacterial strains. The best results were obtained with Propionibacterium sher mania. No extracellular proteolytic activity was observed for these bacteria and, in addition, beneficial enrichment of the product with vitamin B12 and propionate, which has preservative effects (Stoianova, EG. Vorobeva, L., Lobzov, Kl. Biokhim, Mierobiol. 1976, 12, 4, 629-35).

Other authors have tested several strains of the genus Lactobacillus for saccharification of egg whites. in particular L. brevis, I ,. in time i, L. ferrnenti and L. plantarum (Mulder, R. W. A. W. Bolder, N. M.).

The non-pathogenic Escherichia colL strain found naturally in egg white was also tested for fermentative glucose removal while inhibiting the growth of dangerous bacteria of the genus

Salmonella, which are the major pathogenic microbial contaminant of eggs (Mickelson, M.

C7. 300210 B6

N., Flippin, R.S. Use of Salmonellae Antagonists in Eermenting Egg While IL Microbiological Methods for Elimination of Salmonellae Frorn Egg White. Appl Microbiol. 1960, June 8, 371377).

The use of glucose oxidase enzyme to eliminate glucose in egg and egg white has been described in several publications (eg: Baldwin, RR, Campbell, HA, Tbiessen, R., Lorant, GJ). Food Technol 1953: 7: 275-82; Rao TSS Murali HS Evaluation of compressed bakers-yeast as a substitute for glucose - oxidase for desugaring egg melangc J Food Sci Technol Mysore et al 1985: 22: 47 -51). The enzyme glucose oxidase is mostly isolated from the fungus of Aspergillus niger for industrial purposes.

Since higher concentrations of hydrogen peroxide can oxidatively degrade parts of protein molecules and inhibit the further course of enzyme glucose oxidation, it is necessary to use glucose oxidase in combination with another enzyme, catalase, which breaks down the formation of hydrogen peroxide into water and oxygen molecules. Another function of catalase in commercial enzyme preparations for saccharifying battle and egg mass (eg Ovazyme, Novozym) is to provide the free oxygen molecules necessary for the oxidation of glucose to D-glucono-1,5laclone by the enzyme glucose oxidase. For these reasons it is in the saccharification of egg white or egg mass

Hydrogen peroxide is also added to the mixture by this enzyme system, which after decomposition by catalase provides a sufficient source of oxygen molecules necessary for the oxidative decomposition of glucose.

The use of soluble glucose oxidase allows only batch processes and in addition the enzyme remains as a contamination in the final product. For this reason, numerous attempts have been made and published to immobilize this enzyme in combination with catalase on various carriers, immobilizing this enzyme system would allow a continuous process for saccharification of egg mass and egg whites without releasing enzymes into the final product. These experiments are discussed by Sisak, C., et al. (Sisak. U., Csanadi, Z .. Ronay, E., Szajani, B .: Elimination of glucose in egg white using immobilized glucose oxidase. Enzyme Micrub. Technol. In Press. Corrected Proof, Available

3 (also online 6 March 2006). The authors of this publication immobilized the commercial enzyme system NOVOZYM 77E containing glucose oxidase and catalase to an anion exchange resin Amber Lite UP 900 using absorption and subsequent cross-linking with glutaraldehyde. The enzyme mobilized in this manner was successfully used to de-sacrifice egg white on a pilot scale in a three-stage fluid / m biorcactor, and the process was designed for industrial use.

The methods described above for industrial glucose removal, however, have some disadvantages.

Among the major disadvantages of industrial use of commercial enzyme preparations containing

4 (both glucose oxidase and catalase include:

Hydrogen peroxide can partially oxidatively degrade parts of protein molecules, eg amino acids cysteine and methionine in protein chains

- higher price of enzyme preparation

In the case of industrially used ferritic methods, the main disadvantages also include:

- the need to use a complex nutrient medium in the preparation of the microbial inoculum. usually containing yeast extract and other ingredients leading to a higher cost of the final product

- possible sensory defects of the final product (eg yeast aftertaste and odor)

- the need to conduct the fermentation at higher temperatures to achieve a sufficient rate of glucose removal, leading to a higher risk of multiplication of risk bacteria (with the exception of the process of GB 606 292. in which fermentation is conducted at temperatures above 45 ° C) and higher cost of the final product.

Cl 300210 136

The aforementioned disadvantages are substantially eliminated by a new fermentation process utilizing the fermentation process of the yyveromyces or Fahospora.

SUMMARY OF THE INVENTION

The above-mentioned deficiencies are eliminated by the process of de-saccharification of egg white and melange according to the invention, which consists in that the presence of glucose in liquid egg white or homogenised egg mass is reduced to the desired level by batch or continuous fermentation. products after the addition of a sufficient quantity of biomass of lactic yeasts of the genera Khtyveroniyces í Fahospora at a temperature of 5 to 45 ° C and a pH of 4 to 8.

The process according to the invention is further characterized in that, in a preferred embodiment, the saccharification takes place at a yeast biomass concentration of 0.7 to 1.3 g / kg, at a temperature of 10 to 20 ° C and a pH of 6 to 7.

The method according to the invention is further characterized by this. that de-saccharification takes place with yeast biomass. immobilized on a suitable carrier.

The invention relates to the use of dairy yeasts of the genera Khtyveroniyces or Fahospora for the fermentative removal of glucose from egg melange (which is a complete homogenized egg mass after removal of the shell) and egg white before drying in order to eliminate unwanted brown coloration of the final product and extend its shelf life. Fermentaee is terminated when the desired minimum glucose concentration is reached and the egg white and melange are further processed in the usual manner.

Glucose is converted under the conditions of the process according to the invention by yeast biomass into harmless metabolic products, in particular ethanol and carbon dioxide, which are present in the final product in trace amounts at most. The rate of fermentation degradation of glucose is

5o proportional to the concentration of yeast biomass in liquid egg white or egg melange. Milk yeast in the method of the invention replaces baker's yeast or some bacterial strains which have hitherto been used on an industrial scale for fermentative degradation of glucose.

The main advantages of the novel fermentation process according to the invention using yeast strains of the genus Khtyveromyces or Fahospora as compared to traditionally used processes are:

easy and cheap preparation of standard quality yeast inoculum in simple whey medium without the need for essential factors

- elimination of unnatural taste and odor when compared to baker's yeast or brewer's yeast

- there is no change in the pH of egg mass or egg white by metabolic products

- the possibility of keeping the fermentaee at lower temperatures while maintaining a sufficient rate of glucose removal leading to inhibition of growth and multiplication of risk bacteria and a reduction in the price of the final product

The egg melange or egg white fermentation according to the invention can be carried out in a batch process or economically and technologically advantageously in a continuous process. Furthermore, the fermentation biomass may be freely suspended in egg white or melange or immobilized by any of the methods described in the literature. The advantage of using immobilized yeast biomass is that yeast cells do not pass into the end product and therefore cannot be sensoryly influenced by it. A further advantage of using a biocatalyst formed by immobilizing yeast cells on a solid support is that it can be reused several times. By the process according to the invention, the desired end product is obtained cheaper and its shelf life is prolonged.

-4 C7 30021 «B6

The following examples illustrate the process according to the invention without limiting it in any way.

DETAILED DESCRIPTION OF THE INVENTION

Example 1 ni Comparison of the efficacy of the yeast strain Saceharomyces cerevisae and Fabospora fragUis in the fermentative removal of glucose from egg white

Inoculum of the yeast Fabospora fragiiis strain was prepared by seeding with 400 ml of sterile medium containing 10 wt. Whey powder with addition of 0.3 g KCk OJ g NaCl and OJ g (NH 3 O 3) by washing the yeast cells from slanted agar. 24 hours.

Two 500 ml fresh egg white eggs were weighed into two 1000 ml Erlenmeyer flasks. The pH of the egg white was adjusted by adding 10 wt. of hydrochloric acid solution to 6.4. To the first flask was added 5 ml of inoculum prepared by suspending 33J g of fresh compressed yeast (eg Pala brand) with a dry matter content of 30.2% by weight. in saline and make up to 100 ml. The resulting dry weight of the baker's yeast was 1 g. kg Into a second flask was added 12 ml of inoculum containing yeast bioinase

Fabospora fragiiis prepared as described above. The resulting dry matter of this yeast biomass in liquid white was again 1 g. Both Erlmnmayer flasks were sealed with cotton plugs and the egg white fermentation was carried out in a thermostat under semi-aerobic conditions on a shaker with slow stirring at 30 ° C.

Soil samples were taken at regular time intervals to determine glucose concentration. The glucose determination was performed using test strips (jlukophau (Pliva-Lachema). The principle of the method is the oxidation of glucose by the enzyme glucose oxidase. The glucose oxidase reaction is practically specific for glucose.

The resulting hydrogen peroxide is decomposed by catalase and the liberated oxygen oxidizes the colorless chromogen to a blue-green complex. The coloring of the reaction zone on the test strip after immersion in the sample is compared with the coloring of the zone on the color scale adhered to the packaging rhino and evaluated seinquantitatively. The manufacturer reports a positive reaction at a concentration of 300 mg.l ^! (-1.67 mmol.l ').

After 5 hours of fermentation, the glucose concentration in both flasks was below the detection limit of the method. Thus, the rate of glucose degradation in both yeast strains is comparable at this temperature and the product obtained has no undesirable brown coloration.

Example 2

Fermentation of egg white at 20 ° C

500 grams of fresh egg whites were weighed into two 1000 ml Erlenmeyer flasks. The pH of the egg white was adjusted by adding 10 wt. hydrochloric acid solution to 6.4. To the first flask was added 2 ml of inoculum prepared by suspending 33 µg of fresh pressed yeast (e.g. Fata brand) with a dry matter content of 30.2% by weight. in saline and make up to 100 ml. The resulting dry yeast dry matter was 400 mg kg. 4.8 ml of the same yeast strain inoculum was added to a second flask.

Fabospora fragilis as in Example 1. The resulting dry matter of this yeast biomass in liquid egg white was the same as in the case of baker's yeast, i.e. 400 mg. kg

Both Erlenmayer flasks were sealed with cotton plugs and the white fermentation was carried out under semi-anaerobic conditions on a shaker with slow stirring at 20 ° C.

White samples were taken at regular time intervals to determine glucose concentration. The glucose determination was again carried out in the same manner as in the previous example. After 12 hours of fermentation, the glucose concentration in the case of egg white with the addition of yeast biomass Fabospora fragi / is below the detection limit of the assay method (<300 mg.l -1). However, in the case of egg yeast with the addition of baker's yeast, the residual glucose concentration was still in the range of 500 to 1000 mg.l

The gemi-degradation of goat glucose usually occurs at a sufficient rate even at 20 ° C using the yeast Fabospora fragilis strain, while the rate of fermentation at this temperature is lower when baker's yeast is used.

The product obtained is white and has an extended shelf life.

Industrial usability

Dried egg melange and eggplant are important raw materials used in many pot2 sectors? and the wine industry. In many industrial applications, these dried products replace fresh eggs.

Claims (3)

PATENT CLAIMS CLAIMS 1. A process for the de-saccharification of egg white and inelement, characterized by a screen. The method of claim 1, wherein the presence of glucose in the liquid egg white or liomogenized egg mass is reduced to the desired level by fermentation in a batch or continuous manner to produce ethanol. of carbon dioxide and any other metabolic products after addition of a sufficient quantity of milk yeast biomass of the genera Kht \ xerom \ resìi Fabospora at a temperature of 5 to 45 ° C and a pH value 4 to 8. Process according to claim 1, characterized in that the de-saccharification takes place at a yeast biomass concentration of 0.7 to 1.3 g / kg, at a temperature of 10 to 20 ° C and a pH of 6 to 7. 3. The method of claim 1, wherein the de-saccharification takes place with fermented 45 biomass immobilized on a suitable carrier.