JPH0534939B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a yeast extract characterized by containing a large amount of taste-producing 5'-mononucleotides. More specifically, ribonucleases that hydrolyze ribonucleic acids in the yeast cells into tasteless 2'3'-nucleotides are inactivated in advance, and then lytic enzymes are applied to further generate 5'-nucleotides. The present invention relates to a method for producing a yeast extract with extremely high taste, which is characterized by allowing 5'-phosphodiesterase and 5'-adenylate deaminase to act together with protease.

[Conventional technology]

Yeast extract has recently been increasingly used as a natural seasoning, in contrast to the trend of monosodium glutamate, a chemical seasoning, peaking out. This is due to the fact that there is an increasing preference for natural products as ingredients for recent food products, and yeast extract has a strong taste and is similar to meat extract.

The flavor components of yeast extract include amino acids, peptides, sugars, and 5'-nucleotides. Among these, amino acids and peptides are known as components that give yeast extract its unique flavor, and 5'-nucleotides are known as components that give ``umami'' flavor.

Generally, autolysis methods, enzymatic decomposition methods, and the like are known for producing yeast extracts, but all methods generally utilize lytic enzymes and proteases within bacterial cells.

[Problem that the invention seeks to solve]

In this case, during the lytic process, ribonucleic acid is hydrolyzed into 2'3'-nucleotides, which have no taste, by the action of ribonuclease in the bacterial cells, and 5'-nucleotides, which have taste, are not produced. The reality is that yeast extract with strong umami flavor cannot be obtained because the amount is extremely low. Regarding this point, a method is known to adjust the pH during autolysis in order to prevent hydrolysis to 2'3'-nucleotides and increase the yield of 5'-nucleotides (Japanese Patent Publication No. 1986-92672, Kimiaki
59−109153).

However, in the conventionally known method, 5′−
The yield of nucleotide production is low, and a large amount of 2'3'-nucleotides are observed, making it difficult to say that this is a satisfactory method.

[Means and actions for solving problems]

As a result of extensive research, the present inventors have found that the cause of this is that it is difficult to completely suppress the ribonuclease activity that produces 2'3'-nucleotides in the bacterial cell by adjusting the pH alone, and therefore, it is possible to eliminate autolysis without autolysis. After completely inactivating the ribonuclease by heating, a lytic enzyme is applied and then freshly prepared.
We have found a method of adding 5'-phosphodiesterase, 5'-adenylate deaminase, and protease that generate 5'-nucleotides. This method deactivates most of the enzymes, including protease within the bacteria, so it has the disadvantage of requiring the addition of extra protease, but it does not improve the taste.
It has the great advantage of extremely high yields of 5'-nucleotides, so it can be said to be an extremely excellent method for producing yeast extracts with high flavor, now that various proteases are readily available. .

In the present invention, the yeast that can be used as a raw material for the yeast extract is not limited to commonly used brewer's yeast and baker's yeast, as long as it is suitable for food; Examples include various yeasts such as those of the genus Hansenula.

In the present invention, the heating temperature during heating to deactivate intracellular enzymes is preferably 80 to 100°C, particularly 90 to 100°C, and the heating time may be 2 to 20 minutes, and usually 10 minutes is sufficient.

The order of addition of each enzyme is that after adding the cell wall lytic enzyme, the order of adding the remaining three enzymes, that is, 5'-phosphodiesterase, protease, and 5'-adenylate deaminase, is not particularly limited.

Furthermore, there are no particular limitations on the amount added, the enzyme reaction temperature, or the pH, and it is sufficient to carry out the reaction under the optimal conditions for each enzyme. Regarding the reaction time, in the case of cell wall lytic enzymes, it is usually sufficient to react for 1 to 5 hours, and then the remaining three enzymes are added and reacted for 10 to 20 hours to complete the enzymatic reaction. .

The subsequent post-treatments are carried out in accordance with the conventional method for producing yeast extracts.

〔effect〕

Yeast extract produced by conventional methods has a low content of taste-producing nucleotides, so it is necessary to supplement the taste by adding a chemical seasoning such as sodium glutamate during food preparation. There were aspects of this that were contradictory.

However, since the yeast extract produced by this method contains an extremely large amount of 5'-nucleotides, which have a taste, there is no need to supplement the taste with chemical seasonings, and food products can be prepared using only natural products. It is not only easy to prepare, but also very economically advantageous.

〔Example〕

Hereinafter, the present invention will be described in more detail.

Example 1 1000ml of beer yeast slurry (13% bacterial cell concentration)
After heating at 85°C for 10 minutes, cooling to 50°C, cell wall lytic enzyme [trade name: YL-5, (manufactured by Amano Pharmaceutical Co., Ltd.])
Add 2.6g of and react for 6 hours. Thereafter, the temperature was raised to 65°C, and the temperature was increased to 200 °C.
mg was added and reacted for 3 hours, then cooled to 50°C and treated with proteolytic enzyme protease [trade name: Nagase,
(manufactured by Nagase Sangyo Co., Ltd.)] and 20 mg of 5'-adenylate deaminase (manufactured by Amano Pharmaceutical Co., Ltd.) were added and reacted for 10 hours.

After cooling, it was treated according to a conventional method to obtain 95 g of yeast extract. The contents of sodium 5'-inosinate and sodium 5'-guanylate in this yeast extract are
They were 1.9% and 2.0%.

In addition, the contents of sodium 5'-inosinate and sodium guanylate in the yeast extract obtained by the same treatment without heating at 85℃ for 10 minutes were respectively
They were extremely low at 0.5% and 0.6%.

Example 2 Slurry of Candida utilis (ATTCC 9226)
Heat 1000ml (bacteria cell concentration 13%) at 100℃ for 10 minutes,
The yeast extract was treated in exactly the same manner as in Example 1 to obtain 98 g of yeast extract. The contents of sodium 5'-inosinate and sodium 5'-guanylate in this yeast extract are
They were 2.1% and 2.3%.

The contents of sodium 5'-inosinate and sodium 5'-guanylate in the yeast extract obtained by the same treatment without heating at 100℃ for 10 minutes are respectively
They were 0.4% and 0.6%.

Claims (1)

[Claims] 1. After heating the yeast cell suspension to 80 to 100°C to inactivate proteases and ribonucleases within the cells, add cell wall lytic enzymes to act, and then further inactivate 5'-phosphodiesterase and 5'-adenyl. A method for producing a yeast extract, which comprises producing a large amount of tasty 5'-nucleotides through the action of acid deaminase and protease.