NL9002074A - PROCESS FOR IMPROVING THE TASTE OF FOOD PROTEIN, AND FOOD PREPARED SO. - Google Patents

Description

A method for improving the taste of food protein, as well as foods thus obtained.

The invention relates to a method for improving the taste, in particular debitting, of hydrolysed protein.

Bitterness can be a problem in almost any type of food. In some products, the bitter taste does not always occur and can be related to the degree of maturity, growing conditions and / or environmental factors. On the other hand, the bitter taste can always be present in other products, even after dilution of the product with a non-bitter product. For many, if not all, products, bitterness is considered a sensory defect. The problem is exacerbated because within a group of people there is a large variation in the degree to which bitterness is experienced. Some people can already taste bitterness at extremely low concentrations, while others can only taste it at very high concentrations. Bitterness is also often accompanied by a long aftertaste.

Protein products are an important group of foods where the problem of bitterness can arise. Especially hydrolysed proteins, whether or not split by proteolysis, from milk, fish, chicken and soy are plagued with a bitter taste, in particular after continued hydrolysis. This hydrolysis is often desirable to improve solubility and / or digestibility. Many of the amino acids that contribute to the bitterness of protein hydrolysates are also essential, for example, in people's diets.

The bitter taste of, among other things, milk products is mainly caused by the presence of bitter-tasting amino acids and peptides that arise from the splitting of (milk) proteins. This may be the case with ripened hard cheese products, the by-product whey and milk products processed according to the UHT (Ultra High Temperature) process.

In addition, this problem occurs very strongly in the hydrolysis of soy proteins. For the application of soy proteins, hydrolysis is necessary to improve functional properties of the protein as well as increase solubility. The bitterness of soy protein is the result of the release of bitter peptides of different molecular weight. The bitterness intensity is not related to the molecular weight but to the amino acids occupying the C-terminal position and the amino acid composition. This also applies to the aforementioned cases. Most of the peptides from soy hydrolyzates tested contained at least 50% of the relative hydrophobic amino acids phenylalanine, valine, leucine and isoleucine. A general rule is that the intensity of the bitter taste is correlated with the degree of hydrophobicity and also that in bitter tasting aqueous solutions there is an inverse relationship with the surface tension.

A number of methods are known for the removal of the bitter constituents from protein hydrolysates, in particular from soy proteins: 1. Separation with solvents 2. Precipitation by, inter alia, cyclodextrins 3. Hydrophobic column chromatography 4. Membrane filtration 5. Microorganisms.

Ad 1 An azeotrope of water and sec-butanol can be used to remove bitter components from soy. About 5 to 10% of the total hydrolyzate must be removed for complete debit. The disadvantage is that the use of solvents, in particular alcohols, can be expensive on an industrial scale. Also, water in mixtures with organic solvents reduces the solubility of the soy protein resulting in impairment of functionality in food products (see DH Honig et al., J. Food Sci. 4l, 642-646 (1976); G. Lalasidis and LB Sjöberg, J. Agric, Food Chem. 26, 7 * 12-749 (1978)).

Ad 2 Cyclodextrins can be used to remove bitter tasting proteins from soy. To this end, up to 30% by weight of cyclodextrins relative to soy (solid) is added in a batch process. In this case, however, according to Japanese Patent Application JP-A-5I / 184052 (1976) (JP-B-83 / 43O62), only lipid oxidation products and possibly phenolic acids and isoflavones are removed. However, according to this publication, the use of cyclodextrins to remove bitterness induced by protein hydrolysis is excluded. JP-A-57/18948 (1982) and JP-A-58/175447 (1983) (JP-B-83/50705 and JP-B-9O / 2315O) disclose the use of citric acid at low pH using acidic protease to hydrolyze the protein (24 h) and then neutralize with calcium hydroxide. The addition of calcium hydroxide causes a precipitate to be removed by centrifugation. A tasty product is formed that is free from bitterness. However, the very presence of this flavor may hinder the use of certain nutritional applications.

Ad 3 Bitter and non-bitter peptides can be separated by hydrophobic chromatography due to their hydrophobic and hydrophilic properties (G. Lalasidis and LB Sjöberg, J. Agric. Food Chem. 26, 742-749 (1978); JF Roland et al. J. Food Sci. 4, 1491-1493 (1978)). Disadvantages are the high cost of the column material and the long process time.

Ad 4 Membrane filtration separates molecules based on size. Debittering of soy is possible with this technique, because the bitter peptide components are often much smaller than the non-bitter macromolecules. Ultrafiltration is an effective and versatile process for the removal of flavors from soy. The denaturation of protein is minimal. Many types of membranes and reactors are already available. An important point is the service life and shelf life of the membranes, because many cycles of cleaning and use have to be endured (see 0. de Rham et al., J. Food Sci. 43, 642-643 (1978); JP Roozen and W. Pilnik, Enzyme Microb Technol 1, 122-124 (1979); WD Deeslie and M. Cheryan, J. Food Sci., 46, 1035-1042 (I98I)).

Ad 5 The use of microorganisms for the debittering of soy is still in its infancy. U.S. Patent 4,315-946 and J.T. Johansen et al., C.R. Trav. Lab. Carlsberg, 36, 365-384 (1968) describes microorganisms capable of converting bitter amino acids and peptides into flavors and compatible with certain foods (cheese). To control and prevent bitterness in cheese, special starter cultures with reduced proteolytic capacity are used and the conditions during processing are adjusted. Hygiene is an important factor in solving problems with milk products prepared according to the UHT process. By M.L. Speek and D.M. Adams, J. Dairy Sci., 59, 786 (1976) addresses the drawbacks of using microorganisms.

From Dutch patent application 8100280 it is known to add strongly water-swelling carbohydrates to a protein substrate simultaneously with protein splitting enzymes, whereby a higher degree of hydrolysis is obtained before reaching the "bitter point". However, in such a method, the protein composition is changed.

The object of the invention is to provide a method with which the unpleasant taste, in particular the bitter taste, of hydrolysed proteins can be efficiently reduced, without the disadvantages of the methods known for that purpose.

The process according to the invention is characterized in that a substantially linear polysaccharide is added to the hydrolysed protein.

The method according to the invention has the following advantages:

Because the unwanted flavor carriers can be masked and do not have to be separated, all protein components, and thus also the essential amino acids, remain in the product. For example, if the mixture is spray dried in its entirety, no amino acids are removed. This is in contrast to the known methods, according to which the bitter taste components are always removed.

The method is simple and therefore inexpensive, thanks to the possibility of spray drying and, when starch, amylose or amylose dextrins are used, of pellet formation.

- Hydrophobic, and promoting a bitter taste, amino acids and peptides are included. This is in contrast to the known method (JP-A-51/1 ^ 8052), which uses cyclodextrins and which is said to be unsuitable for removing bitterness due to protein hydrolysis.

The price of the polysaccharides to be used can be much lower than that of the cyclodextrins to be used by any of the known methods.

New taste deviation, for example by citric acid as in the method according to JP-A-58/1754 ^ 7 * is prevented.

The protein hydrolysis is not influenced per se, as is the case with the method according to NL-A-8100280, whereby the properties of the product are retained.

An explanation for the fact that the bitter taste and any other unpleasant taste is reduced or reversed with the method according to the invention can be that the polysaccharides used complex the hydrophobic, bitterness, peptides and / or amino acids, thereby preventing that the bitter taste is expressed. However, other statements are by no means excluded.

By the term "substantially linear polysaccharides" is meant polysaccharides which are not significantly branched with long side chains and do not have a cyclic structure. This excludes, for example, amylopectin and cyclodextrins, respectively.

Eligible polysaccharides are, for example, 1,4-α-glucans (polysaccharides consisting largely of anhydroglucose units attached to the α-1 position and the 4 position glycosidically). This includes, for example, starch and fractions and derivatives thereof, such as amylose and dextrins. Since a spiral structure of the polysaccharide may play a role in bitterness masking, 1,3-glucans, for example microbial polysaccharides such as curdlan and scleroglucan, may also be used. Furthermore, in principle other, largely linear, polysaccharides, including those containing units other than glucose, are also eligible.

Preferred according to the invention are α-1,4-glucans, in particular those which have a chain length (degree of polymerization, DP) of at least 5. Especially preferred are at least 12 anhydroglucose units per molecule. Very long chain polysaccharides are useful, but the effect is not proportionally greater. Therefore, a chain length of up to about 100 anhydroglucose units per molecule is preferred in practice. As such, linear amylose dextrins have proved particularly suitable. These can be prepared from starch by gelatinization followed by 1,6 branching, for example, enzymatically with 1,6-glycosidases. The de-branching does not have to be complete to obtain a good debittering effect. Suitable 1,6-glycosidases are, for example, pullulanase and isoamylase.

The starch from which the polysaccharides to be used according to the invention can be prepared can in principle be any type of starch. Examples are corn, wheat and potato starch.

The amount of polysaccharide to be used depends on various factors, such as the method followed and the intended purpose (further processing of all the protein material or after separation of bitter constituents), the strength of the bitter taste of the starting protein, the nature of the protein and of the polysaccharide, and the requirements of the product. Generally, 0.1-20% by weight of polysaccharide is used relative to the protein. Preferably 0.5-5 wt. Equivalents and more in particular about 1-3 wt. Equivalents are used.

Proteins and protein derivatives which can be debittered by the method of the invention include all food proteins and derivatives thereof, in particular hydrolysed proteins, because bitterness is a particular problem here. The proteins are in particular milk, soy, chicken and meat proteins or degradation products thereof such as hydrolysates and other (oligo) peptides. These are especially proteins with a high content of hydrophobic amino acids, such as valine, leucine, isoleucine and phenylalanine.

The implementation of the method according to the invention does not require any special provisions. The polysaccharide can simply be added to a solution or suspension of the hydrolysed protein and kept in contact with the protein for some time. The entire mixture can then be suitably worked up, for example by spray drying. If desired, an optionally formed precipitate containing bitter taste components can also be separated. The method can be set up batchwise or continuously.

Examples; General a. Materials

The dextrins are prepared from starch by treatment after gelatinization of the starch with pullulanase for 20 hours at 55 ° C. The pullulanase used was Promozyme (NOVO) in an amount of 4-10 units (PUN) / g starch. Pepton III (soy protein) and Pepton IV (soy protein hydrolyzate) were supplied by Sigma Chemicals. Bitter casein hydrolyzate BV18 and Bitter casein hydrolyzate BV50 were supplied by the "Melkindustrie Veghel BV" * (division of DMV-Campina).

b. Preparations of the starting materials

All examples were based on solutions prepared as follows. The linear dextrins were dissolved in water at 100 ° C. The proteins and protein hydrolysates could be dissolved in water at 50-80 ° C, with the exception of the protein hydrolyzate BV50. Even after heating for a long time at 100 ° C, a small part of it remained as undissolved, greasy foam. This could be removed by centrifugation. This residue was found to be odorless and tasteless.

c. Work-up techniques

Spray drying of the suspensions was carried out using a Büchi laboratory spray dryer. The inlet temperature was 110 ° C; the outlet temperature was about 70 ° C. Freeze-drying was carried out according to known techniques. The samples were tastefully assessed by a panel consisting of 12 employees who were not informed about the target, of which 8 men and 4 women.

Example I

A mixture of 10 grams of linear dextrins (obtained from waxy maize by treatment with 10 pullulanase units per gram of starch) and 2 grams of BV18 in 130 ml of water was prepared. After cooling, a very finely divided precipitate formed. The entire mixture (including precipitate) was worked up by spray drying. About 7 grams of white powder were obtained, which was assessed by the majority of the panel (8 members) as not bitter and not unpleasant tasting. Two panel members found the taste not significantly different from that of the starting preparation BV18. The taste of the linear dextrins was considered neutral by all panelists,

i.e. not pleasant and not unpleasant, experienced. A duplicate experiment gave the same results. It should be noted that the residue on the glass walls of the spray dryer had the same taste as the collected material. Example II

In the same manner as described in Example 1, a bitter casein hydrolyzate, but now BV50, was processed. Seven of the 12 panelists weakly recognized the taste of the starting material, but rated the obtained material as not unpleasant, in contrast to the starting material, which was experienced as very unpleasant. Even now there were two panel members who noticed only a small difference, and also judged the taste of the starting protein BV50 as not extremely unpleasant.

Example III

Following the same procedure as in Example I, soy protein (peptone III) was treated with linear dextrins. According to the majority of the panel members, the non-bitter, but unpleasant taste turned out to be hardly present.

Example IV

Soy protein hydrolyzate (Peptone IV) was treated according to the procedure described in Example I. According to the majority of the panel, the resulting material no longer tasted bitter. Some still vaguely recognized the taste of the starting material.

Example V

Ten grams of bitter casein hydrolyzate (BV 50) were centrifuged after heating in 300 ml water at 100 ° C. This resulted in approximately a 0.5 gram loss. To this was added 10 grams of linear dextrins (obtained as in Example I) dissolved in 100 ml of water. After stirring at room temperature for a day, a precipitate formed which was removed by centrifugation. The clear, light yellow solution was evaporated by freeze drying. A very bulky, light yellow powder was obtained. In contrast to the starting material, the taste was considered not unpleasant by all panel members. The centrifuged precipitate was resuspended in water and spray dried. The taste of this material was generally found to be somewhat oily.

Example VI

Repetition of example V, but with 16 grams of dextrins. The results were similar to those of Example V. Three subjects rated the taste of this preparation somewhat more favorably than that obtained in Example V.

Example VII

As example V, but with 24 grams of dextrins. The results were equal to those of Example V. This preparation was also evaluated more favorably by three persons than the product obtained according to Example V. Most panel members found the product to taste better than the starting materials.

Example VIII

10 g wheat starch was gelatinized in 100 ml water and then treated with 0.5 ml pullulanase (10 units PUN per g) at pH = 5. After incubation at 55 ° C for 20 hours, a warm solution of 2.5 g peptone IV in 30 ml of water added. A precipitate formed after cooling. After standing for one day, the entire mixture was spray dried at a temperature of 110 ° C. According to all panel members, the bitter taste was no longer recognizable.

Example IX

10 g of potato starch was treated according to the procedure of Example VIII. 2.5 g of protein hydrolyzate BV50 was added, after which the whole was cooled and spray dried. The taste was experienced as pleasant by 10 of the 12 panel members, with a floral accent. Example X.

Example IX was repeated, however, with 40 units of pullulanase per 10 g of starch and with the addition of 10 g of protein hydrolyzate BV50. According to ten panelists, the taste was acceptable and the bitter taste had disappeared; according to four panelists, the product had a slight metallic / aspirin-like aftertaste.

Claims (11)

A method for improving the taste of hydrolysed protein, characterized in that a substantially linear polysaccharide is added to the hydrolysed protein. The method of claim 1, wherein the polysaccharide is an α-1,4 glucan. A method according to claims 1 or 2, wherein the polysaccharide is derived from starch. The method of claim 2 or 3 * wherein the polysaccharide is an amylose dextrin. A method according to any one of claims 1-4, wherein the polysaccharide has a chain length of 12-100 anhydroglucose units. A method according to any one of claims 1 to 5, wherein the protein is a milk, fish, chicken or soy protein. The process according to any one of claims 1-6, wherein an amount of polysaccharide of 0.5-5 weight equivalents relative to the protein is used. Process according to any one of claims 1-7, wherein the resulting mixture is further processed in its entirety. The process according to claim 8, wherein the resulting mixture is spray dried. Process according to any one of claims 1-7, wherein the obtained mixture is further processed after separation of a precipitated fraction. Food for human or animal obtained by the method according to any one of claims 1-10.