WO2002001963A2

WO2002001963A2 - Production of biohydrolysates

Info

Publication number: WO2002001963A2
Application number: PCT/EP2001/005202
Authority: WO
Inventors: Sunil Kochhar; Clara Lucia Garcia-Rodenas; Dharam Vir Vadehra
Original assignee: Societe Des Produits Nestle S.A.; Vadehra, Bina
Priority date: 2000-06-23
Filing date: 2001-05-07
Publication date: 2002-01-10
Also published as: WO2002001963A3; AU2001265935A1; AR030298A1; PE20020073A1

Abstract

A process for the production of a vegetable protein biohydrolysate which comprises forming an aqueous suspension of a vegetable protein in an amount of from 5 to 50 % by weight based on the weight of the suspension, adjusting the pH if necessary, hydrolysing the suspension at a temperature of from 50° to 60 °C with a proteolytic enzyme containing proteases, exopeptidases, endopeptidases or glutaminases by incubating for a period of from 8 to 24 hours to obtain a degree of hydrolysis of at least 60 %, heating to inactivate the enzyme and separating the biohydrolysate.

Description

PRODUCTION OF BIOHYDROLYSATES

FIELD OF THE INVENTION

The present invention relates to a process for the production of biohydrolysates, more particularly to the production of biohydrolysates by the biological hydrolysis of vegetable protein containing material and their use as savoury flavourings.

BACKGROUND OF THE INVENTION

Due to continuous changes in life-styles and trends of our society, the market for prepared foods continues to grow providing new challenges to the food industry to manufacture food which is convenient, nutritionally sensible and cost-effective. As consumers are continuously paying more and more attention to food labels, food companies are responding by substituting chemical ingredients like MSG (monosodium glutamate) and 5 ' -nucleotides, etc. with natural ingredients. Natural ingredients not only provide "shorter consumer friendly" labels but they also enhance the image of the food product. Nevertheless, it goes without saying that the heart of any prepared food is its flavour (aroma and taste) and, therefore, it is important to develop natural ingredients which provide superior flavour enhancement and/or flavour modulation cost-effectively. Hydrolysed proteins have been known for use as seasonings in food systems for centuries in the Far East in the form of soya sauce which traditionally has been prepared by fermentation for a long period of time, usually several months. In producing soya sauce, plant protein containing materials such as cooked soya beans or defatted soy grits together with carbohydrates are inoculated with Aspergilli and the semi solid product is fermented for 2 days to make Koji during which time enzymes are produced which are able to hydrolyse protein and carbohydrates in the moromi stage. The fermented Koji is mixed with a solution of common salt to give moromi which is fermented for 4 to 8 months by the soya lactic acid bacteria and soya yeasts from which the soya sauce is obtained by removing the insoluble fractions from the fermented moromi . However, there are major drawbacks of fermentation technology, viz. 1)Highly specialised equipment is required (major capital investments) , 2) it requires extreme care of the multi-stage process and 3) a strong colour and characteristic flavour is developed. On the other hand, enzymatic hydrolysis of food vegetable proteins using various proteolytic enzyme systems can be carried out within a short period of time (about 8-20 hours) and only requires a temperature controlled vessel equipped with a stirring device. About 100 years ago, a more rapid method of hydrolysing proteins for producing seasonings was developed using hydrochloric acid in which the time required is only a few hours. However, in recent years, the use of acid hydrolysed plant protein (HPP) in culinary applications has been under criticism due to the presence of chloro- compounds which arises from the acid process. Therefore, attempts have been made to develop HPP replacements which can be used as body-givers in culinary applications. Soya sauce is one such suitable replacement. However, owing to the differences in the raw materials and the processing methods involved, the two products, HPP and soya sauce, have some differences in terms of chemical composition and flavour profile. Dosage of soya sauce which can be used as an HPP replacement is limited due to its "fermented" note. The different processing procedures also result in a significant variation in the degree of hydrolysis of the protein containing material to the amino acids . Soya sauce has a lower amino acid content than HPP and this leads to a significantly weaker body in soya sauce than in HPP.

Attempts have been made to develop biohydrolysates from a variety of food vegetable proteins using various proteolytic enzyme systems but the degree of hydrolysis (DH) , i.e. the percentage concentration of free α-amino groups in the sample compared with the total α-amino groups in a similar sample after acid hydrolysis, is not usually more than about 50-55% and is often much less.

SUMMARY OF THE INVENTION

We have now developed biohydrolysates from a variety of food vegetable protein materials using various proteolytic enzyme systems to give products which are neutral in taste and provide good body-giving properties and wherein the degree of hydrolysis is at least 60%.

According to the present invention there is provided a process for the production of a vegetable protein biohydrolysate which comprises forming an aqueous suspension of a vegetable protein in an amount of from 5 to 50% by weight based on the weight of the suspension, adjusting the pH if necessary, hydrolysing the suspension at a temperature of from 50° to 60°C with a proteolytic enzyme containing proteases, exopeptidases, endopeptidases or glutaminases by incubating for a period of from 8 to 24 hours to obtain a degree of hydrolysis of at least 60%, heating to inactivate the enzyme and separating the biohydrolysate . DETAILED DESCRIPTION OF THE INVENTION

The vegetable protein preferably has a protein content of at least 30% by weight and is advantageously in the form of a protein concentrate which usually contains from 30 to 80% by weight of protein. The protein concentrate may be, for instance, wheat gluten, corn gluten, pea protein, rice protein, soy protein, or gossypol-free cottonseed protein. If desired a protein isolate of soy or wheat gluten may be used which contains more than 80% by weight of protein.

If desired, the protein may be denatured before hydrolysis, e.g. by autoclaving at 121°C for from 10-20 minutes or by heating at 90°-100°C for from 10-20 minutes in alkaline conditions. However, denaturation is not necessary.

The amount of the vegetable protein in the aqueous suspension is preferably from 10 to 45% by weight and more preferably from 15 to 40% by weight based on the weight of the suspension. Normally, it is difficult to obtain more than 15% protein in the aqueous suspension due to clumping and high viscosity. Surprisingly, we have found that if a portion of the enzyme, e.g from 25 to 75%, preferably from 40 to 60%, is added to the water before adding the protein, and the remainder afterwards, the protein and carbohydrate content are liquefied and it is possible to achieve suspensions containing above 20% protein, e.g. from 25 to 35% protein. This enriches the product and increases the final yield.

The suspension may be formed by dispersing the vegetable protein in the water with agitation, preferably vigorous stirring. The water used for preparing the suspension may be set at a temperature of from 70°C to 80°C after which the suspension is cooled to 50° to 60°C for the hydrolysis step or the suspension may be prepared using water at a temperature of 50° to 60°C. Preparing the suspension using water at a temperature of 50° to 60°C is especially suitable for wheat gluten, corn gluten and cottonseed.

The proteolytic enzyme containing proteases, exopeptidases, endopeptidases or glutaminases may be a technical enzyme, for instance, Alcalase, Viscozyme, BAN (Bacillus subtilis α-amylase) and Flavorzyme (a protease/peptidase complex and contains exo- and endopeptidases) from Novo Nordisk, or Glutaminase from Amano Pte Lte. Technical enzymes are generally enzymes that have been isolated and purified to remove interfering activities which would be detrimental to processing.

Before hydrolysis, the pH of the suspension is advantageously adjusted to conform with the optimum pH of the enzyme, e.g. Flavorzyme exhibits a broad range (pH 5-7.5) of optimum pH for enzymatic hydrolysis of proteins. Since Flavorzyme contains various proteolytic activities, hydrolysis carried out at different pH's or where the pH is not controlled may show a similar degree of hydrolysis or kinetics but might be different on sensory scores due to different composition of amino acids and peptides. The optimum pH for Alcalase is from 7 to 8.

The enzyme/substrate ratio may be from 0.1 to 4% and preferably from 0.3 to 3%, and more preferably from 0.5 to 2%.

Preferably, the hydrolysis is carried out by incubating for a period of from 12 to 20 hours.

The heating to inactivate the enzyme may be carried out by pasteurisation or by heating at 90°C to 100°C for from, for example 5 to 15 minutes, preferably from 7.5 to 12.5 minutes .

The biohydrolysate may be separated by conventional methods, e.g. filtration, centrifugation, etc.

Afterwards, the biohydrolysate may be evaporated to a concentrated liquid and, if desired, dried, e.g. by spray-drying or vacuum drying to a low moisture content, and finally milled into a powder. The final yield per gram of total nitrogen is at least 2-3 times higher than a conventional soy sauce. The average peptide size (free solubilised N/total solubilised N) is less than 2 indicating high free amino acid amounts and short chain peptides, both of which are well known flavour precursors .There is a high degree of hydrolysis (total alpha N/total N) especially for wheat gluten, and also for other protein sources. There is also a lack of bitterness in all the biohydrolysates produced by the process of the present invention.

The biohydrolysates of the present invention may be incorporated as a general base for the development of process flavours such as boiled and roasted chicken flavours resulting in a balanced flavour profile with enhancement of meaty note. The process is simple and needs no or minimal capital investment in the factories equipped for HPP production.

EXAMPLES

The following Examples further illustrate the present invention.

Example 1

94.091kg water at 75°C and 0.566kg Flavourzyme 1000 (a dark brown liquid prepared from Aspergillus oryzae) ere mixed and 28.218kg wheat gluten were added and homogenised for 2 minutes in a kettle. A further 0.566kg Flavourzyme 1000 were added and the mixture was further homogenised for 20 seconds. The pH of the mixture was adjusted to from 5.6 to 5.8 by adding 0.107kg of a 50% solution of sodium hydroxide. A further 0.266kg water was added together with 0.213kg liquid glutaminase (Glutaminase C100) and 0.213kg palatase.The blend was incubated for 16 hours at 55°C. After the incubation, 23.425kg salt was added and mixed. The mixture was pasteurised at 95°C for 10 minutes, holding the temperature at 95°C for a further 10 minutes followed by cooling to 70°C. 1.857kg of a filter-aid, Celite 545 (a silica based micrometer beads food grade product to make a cake at the filters to avoid clogging for better was added and the mixture was filtered with the filterpress. After filtration, the liquid filtrate was evaporated in a vacuum evaporator at a maximum temperature of 60°C to give a concentrated liquid of 83% solids content. This concentrated liquid was mixed with 0.478kg palm fat, dried in a vacuum drying oven for 1 hour at 85°C at a pressure of 2mbar, cooled and milled to a powder. The yield was 93% and the degree of hydrolysis was 80% (free soluble N/total soluble N in the final product) . Example 2

11.7kg corn gluten and 47kg water at 80°C were mixed and homogenised for 2 minutes in a kettle. The pH of the mixture was adjusted to 8 by adding 0.1kg of a 50% solution of sodium hydroxide. The mixture was cooled to 55°c and 0.24kg alcalase was added. The blend was incubated for 4 hours at 55°C. After the incubation, 0.35kg of flavourzyme was added and the mixture incubated for 12-14 hours at 55°C. 11.7 kg salt and 0.9kg Celite was added and mixed. The mixture was pasteurised at 95°C for 10 minutes, followed by cooling to 70°C. The mixture filtered with a filterpress. After filtration, the liquid filtrate was evaporated in a vacuum evaporator at a maximum temperature of 60°C to give a concentrated liquid of 83% solids content. This concentrated liquid was mixed with 0.478kg palm fat, dried in a vacuum drying oven for 1 hour at 85°C at a pressure of 2mbar, cooled and milled to a powder. The yield was 93% and the degree of hydrolysis was 65%

(free soluble N/total soluble N in the final product) .

Claims

1. A process for the production of a vegetable protein biohydrolysate which comprises forming an aqueous suspension of a vegetable protein in an amount of from 5 to 50% by weight based on the weight of the suspension, adjusting the pH if necessary, hydrolysing the suspension at a temperature of from 50° to 60°C with a proteolytic enzyme containing proteases, exopeptidases, endopeptidases or glutaminases by incubating for a period of from 8 to 24 hours to obtain a degree of hydrolysis of at least 60%, heating to inactivate the enzyme and separating the biohydrolysate.

2. A process according to claim 1 wherein the vegetable protein has a protein content of at least 30% by weight .

3. A process according to claim 1 wherein the protein is in the form of a protein concentrate which contains from 30 to 80% by weight of protein.

4. A process according to claim 3 wherein the protein concentrate is wheat gluten, corn gluten, pea protein, rice protein, soy protein, or gossypol-free cottonseed protein, suspension is formed by dispersing the vegetable protein in the water.

5. A process according to claim 1 wherein a portion of the enzyme is added to the water before adding the protein, and the remainder afterwards.

6. A process according to claim 5 wherein the amount of enzyme added to the water before adding the protein is from 25 to 75% by weight.

7. A process according to claim 1 wherein before hydrolysis, the pH of the suspension is adjusted to conform with the optimum pH of the enzyme.

8. A process according to claim 1 wherein the enzyme/substrate ratio is from 0.1% to 4% by weight .

9. A process according to claim 1 wherein the hydrolysis is carried out by incubating for a period of from 12 to 20 hours.

10. A process according to claim 1 wherein the heating to inactivate the enzyme is carried out by pasteurisation or by heating at 90°C to 100°C for from, 5 to 15 minutes .