JP2604306B2 - Yeast extract high in taste nucleotide and its production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is based on the fact that it contains a large amount of tasteful 5'-nucleotides 5'-guanylic acid and 5'-inosic acid, as well as peptides and free amino acids. The present invention relates to a yeast extract having a high content of taste nucleotides and a method for producing the yeast extract. More specifically, after selectively extracting ribonucleic acid, peptides and free amino acids in yeast cells, the proteases and ribonucleases in the yeast cells are inactivated by heating, and then 5'-phosphodiesterase and 5'-adenylate deaminase are added. To produce 5'-guanylic acid and 5'-inosinic acid, which are tasteful 5'-nucleotides, and have a remarkably high content of tasteful 5'-nucleotides,
The present invention also relates to a yeast extract having a high content of peptides and free amino acids, and a method for producing the same.

[0002]

2. Description of the Related Art Yeast extract has a strong taste and is used as a food material and seasoning in recent years because it has a function of imparting a kokumi taste by blending with other natural seasonings and is inexpensive. It has been used. The taste components of yeast extract are
It is derived from amino acids, peptides, saccharides, 5'-nucleotides and the like. Amino acids and peptides are components that produce the flavor and body taste of yeast extract, and 5'-nucleotide is a component that produces umami.

[0003] In general, methods for producing yeast extract include an autodigestion method and a decomposition method using an acid or alkali. In these production methods, RNA in yeast is non-tasting 2 ', 3'. -Has been decomposed into nucleotides, and the content of tasteful 5'-nucleotides is remarkably low. That is, the conventional yeast extract had a low umami taste as a seasoning due to a low content of 5'-nucleotide as a umami component. In order to compensate for this drawback, umami components such as 5'-inosinic acid and 5'-guanylic acid which had been separately prepared had to be added. But then, the yeast extract is no longer a natural seasoning

[0004] In order to solve such a problem, a method of adding a large amount of 5'-nucleotide to a yeast extract as a natural seasoning without separately adding (1) heating the yeast cells in advance to reduce RNA A method for inactivating ribonucleases that decompose into non-tasting nucleotides (see Japanese Patent Application Laid-Open No. 62-201595), (2) a method in which a yeast cell suspension is treated with a protease at pH: 8 to 11.5 to produce RNA. (See JP-A-59-109153), and (3) a method in which an aqueous solution containing yeast cells is alkali-treated, and then an acid hydrolyzate of a protein and a sugar component are added. Japanese Unexamined Patent Publication No. 2-79954) is known. However, in the methods (1) and (2), 5 ′
-Since many amino acids, peptides and saccharides are extracted in addition to nucleotides, the content of 5'-nucleotide is only about 5%.

[0005] The method (3) is not a pure yeast extract because the process is complicated and a protein hydrolyzate and a sugar component are added later. Further, using yeast cells having a high nucleic acid content such as a mutant strain, the ribonucleases of the yeast cells are inactivated by heating in advance, and then the RNA and the extract are extracted in the pH range of 8 to 12, and then extracted. ′
-Method of reacting phosphodiesterase and 5'-adenylate deaminase to contain a total of 14% by weight or more of 5'-nucleotide (Japanese Patent Publication No. 63-805267, Monthly Food Chemical, June 1990, 5'-I
G-rich yeast extract "Allo-mild" (see Yoshinori Aoyagi Co., Ltd.) is known. However, it can be produced only from a strain having a very high nucleic acid content, and is hardly decomposed even when a protease is added because the protein of yeast cells is denatured in the step of heat inactivation, and peptides and free amino acids are contained in yeast extract. I end up getting less. Therefore, there was a drawback that the yeast extract lacked the body taste.

[0006]

SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art and, despite being a pure yeast extract, tastes 5'-nucleotides 5'-guanylic acid and 5'-guanylate. It is an object of the present invention to provide a taste-rich nucleotide-rich yeast extract containing a large amount of inosinic acid and also a large amount of peptides and free amino acids, and a method for producing the same.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, the yeast suspension was subjected to a temperature at which RNA was not decomposed into non-tasting nucleotides under alkaline conditions under which RNA was easily extracted. Then, the RNA is selectively extracted by terminating the extraction process in a short time to suppress the extraction of other components, that is, by extracting at pH: 8 to 12, 40 to 80 ° C. for 10 to 120 minutes. After that, the extract containing RNA was inactivated by heating, and then reacted with 5'-phosphodiesterase and 5'-adenylate deaminase to reduce 5'-guanylic acid and 5'-inosic acid by 8% each.
As a result, the present inventors have found that a yeast extract containing 16% or more of peptides and free amino acids in total can be obtained, thereby completing the present invention.

In this method, 5'-guanylic acid and 5'-
Since the content of inosinic acid is remarkably higher than that of the conventional yeast extract, it is possible to enhance the umami together with other seasonings and the conventional yeast extract. It also matches the strong needs of the world. In addition, since the enzymes derived from yeast cells are heat-inactivated after extraction, a large amount of peptides and free amino acids are generated. Above all, sodium glutamate is extremely high, and 5'-guanylic acid and 5'-inosinic acid synergistically enhance the taste. It has the function of imparting not only umami but also kokumi as well as an action.

Hereinafter, the present invention will be described in detail. The origin of 5'-phosphodiesterase and 5'-adenylate deaminase used in the present invention is not particularly limited, and commercially available products are sufficient. First, the yeast strain is inoculated into a known medium, cultured, and the obtained cells are separated and washed, and then suspended in water so as to have a yeast concentration of 5 to 20%. The extraction conditions are pH: 8 to 12, preferably pH: 8
Adjust to ~ 10. When the pH is less than 8, the extraction of RNA is not sufficient, and when the pH exceeds 12, it is easily decomposed into non-tasting nucleotides. The reaction is carried out at a temperature of 40 to 80 ° C, preferably 50 to 65 ° C, so that the RNA is efficiently extracted and no decomposition occurs. The time is 10 to 120 minutes, and almost all RNA in the yeast is extracted. If the time is longer than that, the content of other components is increased, and the desired yeast extract cannot be obtained. Thereafter, the suspension was
After inactivating proteases and ribonucleases in the cells at -120 ° C, preferably 90-100 ° C, insoluble residues are removed by centrifugation, and then 5'-phosphodiesterase and 5'-adenylate deaminase are acted on to remove taste. This produces the nucleotides 5'-inosinic acid and 5'-guanylic acid. Thereafter, a powder or paste extract is obtained according to a conventional method for producing yeast extract.

[0010] The yeast extract thus obtained contains more 5'-guanylic acid and 5'-inosinic acid than conventionally known yeast extracts having a high content of taste nucleotides. It contains not less than 8% and 16% or more of peptides and free amino acids having a kokumi-imparting action, so that it has not only a single umami enhancing action but also a kokumi-imparting action. The yeast cells used in the present invention are live yeasts and are edible yeasts of the genus Saccharomyces, Hansenula.
The yeast is not particularly limited as long as it is a genus, Candida yeast or the like, but Candida yeast containing high RNA is particularly excellent.

[0011]

The present invention will be described in detail below with reference to examples.

Example 1 1450 ml of a slurry of Candida utilis (IFO 0619) (cell concentration: 13%) was treated with 4N Na.
The pH was adjusted to 9 with OH, and the mixture was extracted at 65 ° C. for 90 minutes.
After heating at 90 ° C. for 10 minutes to inactivate proteases and ribonucleases derived from bacterial cells, insoluble residues were removed by centrifugation, and the supernatant was adjusted to pH: 5 with HCl, and then ribonuclease P (Amano Pharmaceutical Co., Ltd.) After adding 0.7 g of deaminase (manufactured by Amano Pharmaceutical Co., Ltd.) and cooling to 50 ° C.
The reaction was performed for 2 hours. After standing to cool, treat according to the usual method, 60 g
Of yeast extract was obtained. The contents of 5'-guanylic acid and 5'-inosinic acid in this yeast extract were 8% and 9%, respectively, and the peptide content was 9% and the free amino acid content was 1%.
It was 0%.

Example 2 Saccharomyces cerevisiae
1500 ml of slurry (cell concentration: 12%) of (IFO 0309) was adjusted to pH: 8.5 with 4N NaOH,
Extracted at 60 ° C. for 60 minutes. After heating at 90 ° C. for 10 minutes to inactivate yeast-derived proteases and ribonucleases, the insoluble residue was removed by centrifugation, and the supernatant was adjusted to pH: 5 with HCl, and then ribonuclease P (manufactured by Amano Pharmaceutical Co., Ltd.). ) Was added and reacted at 70 ° C. for 9 hours. After cooling to 50 ° C., 0.2 g of deaminase (manufactured by Amano Pharmaceutical Co.) was added and reacted for 12 hours. After cooling, the mixture was treated according to a conventional method to obtain 70 g of yeast extract. The contents of 5'-guanylic acid and 5'-inosic acid in this yeast extract were 9% and 9%, respectively, and the peptide content was 13%.
% And the free amino acid content was 14%.

Example 3 (Comparative Example 1) In order to examine the umami enhancing effect of the product of the present invention, 10 g of sodium chloride, 2.5 g of sodium glutamate, 20 g of vermicelli, 4 g of dry fine dust, and 1.5 g of dry fine dust Dried soup compositions comprising ginseng and those with and without the product of the present invention and commercially available 5'-inosinic acid and 5'-
A sensory test was carried out by 10 panelists of Yamasa Flavor (manufactured by Yamasa Shoyu Co., Ltd.), which is guanylic acid, in the same amount as the content of 5'-inosinic acid and 5'-guanylic acid of the product of the present invention. Table 1 shows the results.

[0015]

[Table 1]

Comparative Example 2 The procedure of Example 1 was repeated except that the extraction conditions were changed to pH: 7.
Anda utilis (IFO 0619) was treated to obtain a yeast extract. The contents of 5'-guanylic acid and 5'-inosinic acid in this yeast extract were 2% and 3%, respectively, the peptide content was 7%, and the free amino acid content was 13%.
Met. In order to compare the umami enhancing effect of the yeast extract obtained as described above and the product of the present invention, the dry extract was added to the dry soup composition used in Example 3 (Comparative Example 1), and a sensory test was conducted by 10 panelists. The test was performed. Table 2 shows the results.

[0017]

[Table 2]

As can be seen from these results, the product of the present invention has a strong umami-enhancing effect and is not a single umami-enhancing effect such as commercially available 5'-inosinic acid or 5'-guanylic acid. It also has a kokumi imparting effect by other components such as peptide and amino acid, and has an excellent umami kokumi enhancing effect.

[0019]

As described in detail above, the present invention contains a remarkably large amount of tasteful 5'-nucleotides as umami components,
In addition, since it has a high content of peptides and free amino acids having a kokumi taste-imparting effect, the product of the present invention can be used as a substitute for a conventional nucleic acid seasoning for the purpose of enhancing umami, and has a kokumi-imparting effect. It is a completely natural seasoning.

Claims (4)

(57) [Claims] 1. A taste-enhancing nucleus containing 5% or more of 5'-guanylic acid and 5'-inosinic acid, respectively, and 16% or more of peptides and free amino acids in total.
Otide-rich yeast extract. After wherein the yeast suspension was alkali extraction, the intracellular protease and ribonuclease such is heated to inactivate and then reacted with a 5'-phosphodiesterase and 5'-adenylate deaminase, tasty 5 A taste-enhancing nucleoside comprising at least 8% of 5'-guanylic acid and 5'-inosinic acid, each of which is a '-nucleotide, and at least 16% of a total of peptides and free amino acids.
A method for producing a high-pride yeast extract. 3. The alkaline extraction conditions are as follows : pH : 8-12 ,
40 to 80 ° C., the preparation of tasty nucleotide-rich yeast extract according to claim 2, characterized in that 10 to 120 minutes. 4. The condition of heat deactivation after alkali extraction is as follows:
To 120 ° C., the preparation of tasty nucleotide-rich yeast extract according to claim 2 or 3, characterized in that 10 to 30 minutes.