JP2000210056A - Fish extract and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an essence of a fish free from smelling of fish and to provide a method for producing the essence. SOLUTION: A raw material selected from an essence, a soup, a cooking drain and a soluble of a fish and their concentrated or diluted materials is adjusted to weak alkalinity of pH 7-10 and concentrated by heating under reduced pressure to give an essence of a fish having the content of nitrogen (TMA-N) in trimethylamine state based on total nitrogen amount of <=2.5 mg/Ng.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fish extract from which fishy odor has been removed and a method for producing the same.

[0002]

2. Description of the Related Art Extracts of fish (for example, bonito, tuna, sardine, mackerel, horse mackerel, etc.) extracted with hot water or alcohol, auto-digested or enzymatically decomposed fish, or dried bonito, saba-node, and dried sardines Fish extracts, such as boiled juice obtained in the process of manufacturing seafood and steamed broth produced during the production of canned fish, have a strong umami peculiar to fish and are rich in nutritional components. These are used as various seasonings and raw materials for health foods, but their use range is limited due to the strong fishy smell peculiar to fish.

[0003] Fishy odor is mainly generated by volatile basic nitrogen (VBN) such as trimethylamine (TMA), dimethylamine (DMA), ammonia, etc., which are produced by processing such as freezing and refrigeration and subsequent heat treatment. It is well known that it is derived from volatile carbonyl compounds produced by the oxidation of unsaturated fatty acids and low molecular weight compounds such as lower fatty acids such as acetic acid and butyric acid present in polyfatty fish.

In order to remove the above-mentioned unpleasant odor components, various studies have been made and various methods have been proposed. For example, a method in which carbohydrate is added to a seafood extract and lactic acid bacteria or yeast is grown thereon and deodorized (Japanese Patent Laid-Open No. 54-50 / 1979)
No. 57), a deodorizing method in which a high molecular compound such as a proteinaceous substance and starch is added to a fish and shellfish extract, heated, and then treated using an ultrafiltration membrane (Japanese Patent Publication No. 53-8786). A method of suppressing a bad smell by blending a large amount of inosinic acid salts with a kind of extract (Japanese Patent Publication No. 4-56)
No. 585), a method of removing a raw odor by adding and dissolving a saccharide to a seafood extract, and heating the mixture at a temperature of about 130 ° C. (Japanese Patent Application Laid-Open No. 7-289206). There are also a method using an organic solvent such as alcohol, a method using an adsorbent such as activated carbon, and a steam distillation method.

[0005]

However, the above-mentioned processing method has problems that the processing steps are complicated, so that the cost is high, and that the deodorization is insufficient and the raw odor remains.

For example, in the method (1), although a certain amount of fresh odor can be removed, it takes time to grow lactic acid bacteria or yeast.

In the method (1), since the ultrafiltration membrane equipment is expensive and the ultrafiltration membrane treatment takes time,
It is considered that the amount of the processing solution is limited, and it is difficult to industrially process a large amount.

In the method (1), it is considered that inosinic acid and aroma components generated by the heat reaction mask the fresh odor, and the fresh odor component is not fundamentally removed.

In addition, in the steam distillation method, as shown in Comparative Example 2 described below, the removal of the raw odor component is insufficient, and the production process of the extract becomes complicated.

Further, in any of the above methods (1) to (4), it was not possible to remove a fresh odor component to a practically satisfactory level.

Accordingly, an object of the present invention is to provide a fish extract from which a fishy odor component contained in the fish extract has been sufficiently removed, and a method for producing the same.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the fish extract raw material was made alkaline in a specific pH range, and concentrated by heating under reduced pressure to obtain volatile compounds. The present inventors have found that a fish extract in which basic components are efficiently removed and fishy odor is greatly reduced can be obtained, and the present invention has been completed.

That is, the fish extract of the present invention is characterized in that the content of trimethylamine nitrogen (TMA-N) with respect to the total amount of nitrogen is 2.5 mg / Ng or less.

As described above, the fish extract of the present invention comprises one of the volatile basic components, trimethylamine nitrogen (T
Since the content of (MA-N) is 2.5 mg / Ng or less, it can be added to various foods and beverages with almost no sense of fishy odor.

The above-mentioned fish extract is a fish extract,
It is preferable that the raw material selected from a broth, a cooking liquor, a solble, and a concentrated or diluted product thereof is adjusted to a weak alkalinity of pH 7 to 10 and then concentrated by heating under reduced pressure.

Preferably, the fish is selected from skipjack, tuna, sardine, mackerel and horse mackerel.

On the other hand, the method for producing a fish extract of the present invention comprises:
Raw materials selected from fish extracts, broths, steamed liquors, solbles, and concentrated or diluted products thereof are adjusted to a weakly alkaline pH 7 to 10 and concentrated under reduced pressure under heating.

According to the method for producing a fish extract of the present invention,
By adjusting the fish extract raw material to alkalinity in the above specific pH range and concentrating under reduced pressure under heating, volatile basic components can be removed efficiently, and fish extract with significantly reduced fishy odor can be obtained. Obtainable.

In this case, fish extract, broth, steamed liquor,
It is preferable that a raw material selected from solble, a concentrated or diluted product thereof is subjected to enzymatic decomposition in advance, and then concentrated under reduced pressure under heating.

In addition, raw materials selected from fish extracts, broths, cooking liquors, solbles, and concentrated or diluted products thereof are
x. It is preferable to adjust the concentration to 10 to 30%, and then perform the concentration under reduced pressure under heating.

Further, it is preferable that the concentration under reduced pressure is performed by heating to a temperature higher by 10 to 30 ° C. than the boiling point of water under the same pressure as the pressure during the reduced pressure concentration.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION As a raw material for producing a fish extract of the present invention, an extract extracted and decomposed from fish for the purpose of producing the extract by any method, or fish processing (for example, bonito section production, boiled production) Liquids containing fish extract such as boiled juice and steamed broth, auto-digested fish internal organs, or enzymatically decomposed sibles, etc., such as sardine extract, bonito, etc. Extract, tuna extract, horse mackerel extract, bonito soliable and the like.

The fish extract of the present invention can be obtained by removing a raw odor component from the above fish extract raw material by the following method. In this deodorization step, first, a pH adjuster is added to the above-mentioned fish extract raw material (usually weakly acidic having a pH of 5 to 6) to obtain a pH of 7 to 10, preferably 7.5 to 7.5.
Adjust to 8.5. When the pH is lower than 7, the effect of removing the unpleasant odor component is weak, and when the pH is higher than 10, it is not preferable because heating under strong alkalinity may cause the destruction of nutritional components including proteins and flavors. . The above p
Examples of the H adjustor include commercially available flake or liquid sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, and the like, but there is no particular limitation as long as it is an alkali agent that can be used in foods. The pH is adjusted by subjecting the raw material of the fish extract to a pretreatment as described below, if necessary, and then adding the above-described alkaline agent with stirring.

Next, the pH-adjusted fish extract raw material is concentrated under reduced pressure while heating. The heating temperature in the vacuum concentration is appropriately adjusted by the degree of vacuum of the vacuum system. Usually, the vacuum degree of the vacuum concentrator is 300 torr or less, preferably 80 torr or less, and the heating temperature is 10 to 30 ° C. higher than the temperature at which water under the vacuum degree can be boiled by the vacuum degree of the vacuum concentrator. Preferably, it is desirable to raise the temperature by about 15 to 20 ° C. If the heating temperature is lower than 10 ° C., the deodorizing effect is not so high. If the heating temperature is higher than 30 ° C., the concentration rate is too high and the raw odor components are concentrated before being removed.

Since the above-mentioned raw odor components are almost volatile low molecular weight compounds, they can be theoretically removed by vacuum concentration even at a low temperature. However, fish extract is actually composed of various components, Cannot be easily removed because it is in an azeotropic state by being integrated with other compounds. In addition, as the concentration proceeds, the viscosity increases, and the odor components contained therein are less likely to evaporate.Thus, concentration under a higher vacuum is required. When the extract is applied, the extract becomes slightly boiled, and as the water evaporates, the unpleasant odor component also rises to the liquid level and is easily removed.

The degree of concentration can be arbitrarily set in accordance with the type of fish extract, the amount of the raw odor component contained, and the removal efficiency based on the capacity of the vacuum concentration equipment. Generally, the longer the concentration time or the higher the degree of concentration, the more effective it is in removing the raw odor.

In a preferred embodiment of the present invention, an appropriate pre-treatment may be performed according to the state of the fish extract before removing the raw odor component. For example, when the extract contained in the fish extract is small (ex. Bx. 10% or less), the raw material is previously Bx. About 10 to 30%, preferably Bx. 1
It is preferable to start the deodorizing treatment step after concentrating to about 5 to 20%. If the solution is adjusted to alkalinity without pre-treatment and concentrated under reduced pressure, the amount of alkaline agent used for pH adjustment becomes relatively large with respect to the extract, and when concentrated, the salt concentration of the extract increases, resulting in seasoning. The range of use is limited as a fee.

When the fish extract contains a large amount of high-molecular proteins and peptides, it is preferable to decompose the steamed juice with a protease or the like in advance to reduce the molecular weight, and then perform the deodorizing step.
For example, bonito, tuna broth, etc. contain a lot of gelatin eluted from fish skin, fish bone, etc. during the steaming process, so if it is concentrated under reduced pressure as it is, the extract will be removed before the raw odor components are removed. It becomes a paste,
It is not possible to continue the concentration. There is no particular limitation on the type and amount of the protease used, and the reaction temperature and time in the enzymatic decomposition, as long as the molecular weight of proteins and peptides can be reduced to some extent without impairing the flavor of the extract.

[0029]

The present invention will be specifically described below with reference to examples. Example 1 Sardine broth 10 by-produced in the ripening step in the production of dried sardines
kg (Bx. 5.6%) was pre-treated and concentrated under reduced pressure by a conventional method to obtain a concentrated liquid (Bx. 20%). 0.1% by weight of a commercially available protease was added to the amount of the concentrated solution, and 50% by weight was added.
Enzymatic degradation was performed at 3 ° C. for 3 hours. Enzyme digestion solution 1kg, 48%
After adjusting to pH 8 with caustic soda solution, 75 ° C, 75t
orx under vacuum of rr. The mixture was concentrated under reduced pressure to 60% to obtain 330 g of a concentrated liquid containing 2.3% of total nitrogen (TN).

Comparative Example 1 Enzyme-decomposed liquid 1 k of sardine broth prepared in the same manner as in Example 1.
g was adjusted to pH 5 with 6N hydrochloric acid, and Bx.g. was removed under the same deodorizing treatment conditions as in Example 1, ie, at 75 ° C. and a vacuum of 75 torr. Concentration under reduced pressure to 60%, total nitrogen (TN)
335 g of a 2.5% concentrate were obtained.

Test Example 1 The trimethylamine nitrogen (TMA-N) content, ammonia content, and the liquid obtained before and after the deodorizing treatment (Bx. 20%) of Example 1 and Comparative Example 1 were measured. The content and the volatile basic nitrogen (VBN) content were analyzed, and the ratio of the absolute amount of the same component removed to the absolute amount of the raw odor component contained in the liquid before the deodorization treatment, which was obtained by the following equation 1, was determined as the removal rate. And shown in Table 1.

[0032]

## EQU1 ## Removal rate [%] = (amount of component before deodorization treatment-amount of component after deodorization treatment) / amount of component before deodorization treatment

In addition, trimethylamine nitrogen (TMA-
N) The content is determined by the picrate method ("Food Analysis Method", edited by the Japan Food Industry Association, Food Analysis Method Editing Committee, October 1982), where the absorbance of TMA transferred to the organic layer with a strong alkali is measured as a picrate. Published on the 20th, p.673-67
Measured according to 6). The ammonia content is 2-o
xoglutarate + NADH + NH4 ⁺ → L-gl
In the reaction of _{^{utamate + NAD + + H 2 O}} , it consumed the NADH: the amount of (coenzyme involved in oxidoreductase reduced form of nicotinamide adenine dinucleotide) corresponds to the ammonia amount, the decrease in absorbance at 340nm The equivalent amount of ammonia was calculated. The volatile basic nitrogen (VBN) content was measured by a microdiffusion method.

[0034]

[Table 1]

As shown in Table 1, the concentration of Bx. About 20% of fish extract B
x. In Example 1 in which the concentration was reduced to 60%, 70% or more of the raw odor component contained in the fish extract was removed, whereas in Comparative Example 1 in which the concentration was reduced under weakly acidic conditions, the raw odor component was removed. Was hardly removed and remained in the concentrated liquid. Thus, it has been found that concentration under reduced pressure under alkaline conditions is a very effective method for removing raw odor components.

Example 2, Comparative Example 2 As a pretreatment, 20 kg (Bx.9.2%) of tuna broth obtained in the steaming step in the production of canned tuna was concentrated under reduced pressure by a conventional method to obtain a concentrated solution (Bx.20). %). After the concentrated solution was heated to 80 ° C. and allowed to stand overnight to remove oil, a commercially available protease was added to the solid content of the solution at 0.2%.
% By weight and subjected to enzymatic degradation at 50 ° C. for 2 hours. Each 1 kg of this enzyme decomposition solution (Bx. 20%) was adjusted to pH unadjusted (pH
5.5) (Comparative Example 2), and after adjusting the pH to 8.5 with 48% sodium hydroxide solution (Example 2), 70 ° C., 75
Under vacuum of torr, Bx. Each was concentrated under reduced pressure to 60%.

Then, each of the liquids (B
x. The TMA-N, ammonia and VBN contents of the liquid after deodorization treatment (converted to the same weight before deodorization treatment) and the liquid after deodorization treatment were measured.

[0038]

[Table 2]

As can be seen from Table 2, the removal effect at pH 8.5 is very remarkable, and the TMA-
The residual amounts of N and ammonia were only 16.4% and 13.6% of that at pH 5.5, respectively.

In addition, there is a concern that the heating reaction in an alkaline condition may destroy nutrient components such as proteins. However, in the method of the present invention, the content of free amino acids is not so different, and there is no fear that nutrient components are destroyed. Do you get it.

Example 3 The same test was conducted on 14 commercially available products such as skipjack extract, tuna extract, and solibull. Since skipjack extract C and tuna extract A have high viscosities, they were previously treated with a commercially available protease in the same manner as in Example 1. Other samples were used as they were. Take 500g of each sample,
This was diluted to 1500 g with demineralized water, adjusted to pH 8.0 with 48% caustic soda, and then concentrated under reduced pressure to the original weight under a vacuum of 70 ° C. and 75 torr. TMA-N of the concentrate,
Table 3 shows the analysis values of ammonia and VBN.

[0042]

[Table 3]

As shown in Table 3, the commercially available fish extract contains a considerable amount of fishy odor components. However, by carrying out the deodorizing treatment according to the method of the present invention, each fishy odor component becomes about 60-80. % Was also found to be removed.

Example 4 A commercially available skipjack extract (Bx. 65%) was diluted 3-fold in order to confirm the flavor of fish extract from which fishy odor was removed by the method of the present invention and to determine whether or not return odor occurred during storage. And 48
% With caustic soda solution, and then 75 ° C, 75
Under torr vacuum, Bx. It concentrated under reduced pressure to 65%.

Thereafter, the mixture was allowed to stand at room temperature for 3 months together with a stock solution of a commercially available skipjack extract, and sensory evaluation was performed by 10 skilled panelists. Table 4 shows the results.

[0046]

[Table 4]

As shown in Table 4, the bonito extract deodorized by the method of the present invention hardly felt a fishy odor even after storage for 3 months.

Comparative Example 3 1 kg of the enzyme-decomposed solution (Bx. 20%) of the tuna broth used in Example 2 and Comparative Example 2 was adjusted to pH 8.5 with 48% caustic soda solution at 95 ° C. , 45L / m
Steam distillation was carried out for 1 hour through in steam to obtain 665 g of a treatment liquid. This treated liquid was prepared with demineralized water to the same weight as that before the treatment, and the contents of TMA-N, ammonia and VBN were analyzed and compared with the data before the treatment.

[0049]

[Table 5]

As shown in Table 5, in steam distillation under weak alkalinity, 46.6% of TMA-N was removed, but other raw odor components were insufficiently removed, and particularly ammonia was almost completely removed. It was found that it remained without being.

[0051]

As described above, according to the present invention,
The fishy odor component contained in fish extracts such as sardine extract, bonito extract, and soliable can be easily and effectively removed. Further, the fish extract prepared by the method of the present invention does not have a fishy odor and can be used in a wide range of fields.

Claims (7)

[Claims] 1. A fish extract characterized in that the content of trimethylamine nitrogen (TMA-N) is 2.5 mg / Ng or less based on the total amount of nitrogen. 2. Raw materials selected from fish extracts, broths, steamed liquors, solbles, and concentrated or diluted materials thereof are pH-adjusted.
The fish extract according to claim 1, wherein the fish extract is prepared by adjusting to a weak alkalinity of 7 to 10 and concentrating under reduced pressure under heating. 3. The fish, wherein the fish are bonito, tuna, sardine,
The fish extract according to claim 1 or 2, which is selected from mackerel and horse mackerel. 4. A raw material selected from a fish extract, a broth, a cooking liquor, a solible, and a concentrate or dilution thereof,
A method for producing a fish extract, wherein the method is adjusted to a weak alkaline of 7 to 10 and concentrated under reduced pressure under heating. 5. The fish extract according to claim 4, wherein a raw material selected from a fish extract, a broth, a cooking liquor, a solible, and a concentrate or diluent thereof is enzymatically decomposed in advance, and then concentrated under reduced pressure under the heating. Manufacturing method. 6. A raw material selected from a fish extract, a broth, a cooking liquor, a solible, and a concentrate or dilution thereof,
x. The method for producing a fish extract according to claim 4 or 5, wherein the concentration is adjusted to 10 to 30%, and then the mixture is concentrated under reduced pressure under the heating. 7. The fish according to any one of claims 4 to 6, wherein the fish is concentrated under reduced pressure by heating to a temperature 10 to 30 ° C. higher than the boiling point of water under the same pressure as the pressure at the time of vacuum concentration. Extract manufacturing method.