JPS6128370A - Fish protein hydrolyzate and production thereof - Google Patents

Abstract

PURPOSE:To obtain a hydrolyzate having a good amino acid score and little bitterness and fishy smell, etc., soluble even under acidic conditions, and suitable for food protein materials, by reacting a fish protein with alkaline protease, and hydrolyzing the fish protein under specific controlled hydrolysis degree conditions. CONSTITUTION:A fish protein as an aqueous dispersion is reacted with alkaline protease under alkaline conditions, preferably 7.5-9.0pH, and hydrolyzed under 15-25% hydrolysis degree conditions to give the aimed hydrolyzate, containing <=15wt% peptide having >=5,000 molecular weight and <=40wt% peptide having <=500 molecular weight, and having <=10wt% free amino acid and >=70 amino acid score.

Description

[Detailed Description of the Invention] "Category 4) Field" The present invention provides a food made from fish protein that has a high protein content, a good amino acid balance, has little fishy odor, and has little unpleasant taste such as bitterness and umami. The present invention relates to a fish protein hydrolyzate that can be used as a protein material for use in various beverages, particularly as a highly nutritious protein material that is soluble even in acidic conditions, and a method for producing the same.

[Prior art]

Generally, methods for hydrolyzing proteins can be roughly divided into three types: acid hydrolysis, alkaline hydrolysis, and enzymatic hydrolysis. However, in the first two cases.

It is difficult to control the hydrolysis conditions, and the resulting hydrolyzate has a relatively large molecular weight, resulting in precipitation in the acidic region, or conversely, the decomposition progresses to amino acids, resulting in a strong flavor.Also, due to the harsh reaction conditions, It has the drawbacks of poor odor and color, and is not preferred as a protein material for food.

On the other hand, with regard to methods of hydrolyzing proteins with enzymes, there are many examples in which protein sources such as soybeans, casein, and egg whites are hydrolyzed with various proteases to obtain materials for beverages, seasonings, therapeutic foods, etc. Similar attempts have also been made using fish protein as a protein source, and a representative example is the production of liquefied protein from fish carried out at the Tokai Fisheries Research Institute. In this case, if the degree of hydrolysis is low, the recovery rate of the hydrolyzate will decrease, and peptides with relatively large molecular weights, which cause precipitation in acidic regions, are likely to be produced. The drawback is that tryptophan remains in the insoluble category, lowering the amino acid score, which is an indicator of the nutritional value of the hydrolyzate, which is the water-soluble category.
Tokai Water Research Report J 4387-90. Q965)) On the other hand, when the degree of hydrolysis is high, the recovery rate increases, tryptophan increases, and the nutritional value improves, but the amount of small-molecular-weight peptides associated with bitterness increases, and Furthermore, it has the disadvantage that the amount of amino acids produced increases and unpleasant tastes such as bitterness and umami become stronger (``Tokai Suikenho'' 73
, 103-112 (1973)).

As mentioned above, in the conventional method of hydrolyzing fish protein with enzymes, the resulting hydrolyzate has a low amino acid score or has a strong unpleasant taste such as bitterness or umami, which is not desirable as a protein material for food. It has its drawbacks.

〔the purpose〕

Therefore, the present inventors conducted extensive research in order to obtain a hydrolyzate from fish protein that can be widely used as a protein material for food, and as a result, they used fish protein as a protein source, treated it with alkaline protease, and hydrolyzed it. By controlling the degree of hydrolysis within the range of 15% to 25%, (1) the content of peptides with a molecular weight of 5000 or more is 15% by weight or less, and (2) the content of peptides with a molecular weight of 500 or less is 40% by weight. weight% or less.

(3) Free amino acid content is 10% by weight or less, (4) Amino acid score (first limiting amino acid is tryptophan) is 70
We have discovered that a novel hydrolyzate can be obtained that has a good amino acid score as described above, has less unpleasant taste such as bitterness and umami taste, and has less fishy odor, and has accomplished the present invention.

〔composition〕

That is, according to the present invention, the first invention is a water-soluble hydrolyzate of fish protein in which the content of peptides having a molecular weight of 5000 or more is 15% by weight or less, the content of peptides having a molecular weight of 500 or less is 40% by weight or less, Free amino acid content is 10% by weight
There is provided a fish protein hydrolyzate characterized by having the following amino acid scores: A method is provided in which hydrolysis is carried out under alkaline conditions with an alkaline protease acting at a degree of hydrolysis of 15 to 25%.

The present invention will be explained in detail below.

First, the fish protein source used in the present invention may be any source as long as it contains fish protein. For example, fishmeal, commonly known as fishmeal, is commonly used as a protein source. In this case, since the fish meal often contains lipids, it must be degreased in advance with an organic solvent such as hexane or ethanol, and then cleaned. 1+ tll lovely. In addition, protein sources other than fishmeal include whole fish, excluding bones, scales, internal organs, etc., surimi used as raw material for kamaboko, FPC (fish protein concentrate), and marine beef. can. Furthermore, a press cake obtained by shredding, steaming, and pressing raw fish, which is an intermediate product obtained in the production process of fishmeal, can also be used as a protein source. In addition,
Regarding the fish that serves as a protein source, there are no particular restrictions on the type of fish, and any fish such as sardines, cod, mackerel, horse mackerel, etc. may be used.

To carry out the method of the present invention, these protein sources have a protein concentration of 2 to 20% by weight, preferably 4 to 16% by weight.
Disperse in an aqueous medium (usually water) so that If the protein concentration of this dispersion is less than 2% by weight, the cost for concentration and drying will increase significantly, resulting in poor economic efficiency. On the other hand, if it is more than 20% by weight, stirring becomes difficult and enzymatic decomposition is difficult to be carried out quickly, and a homogeneous hydrolyzate cannot be obtained, and the characteristics of the fish protein hydrolyzate of the present invention are not exhibited. Not coming.

The fish protein dispersion thus obtained is then hydrolyzed by the action of alkaline protease. Prior to enzymatic hydrolysis, the pH of the fish protein dispersion is made alkaline, preferably the optimum pH for the enzyme (p) 17.5 to 9.
．． Adjust to 0. If the pH is below 7.5, the activity of alkaline protease cannot be fully exerted, enzymatic decomposition is difficult to proceed, and the recovery rate of the hydrolyzate is significantly reduced. Furthermore, if the pH is 9.0 or higher, the resulting hydrolyzate will have a strong fish odor, which will have a negative effect on quality.

In the present invention, the alkaline protease used for hydrolyzing fish protein is generally one of microbial origin, and for example, any alkaline protease produced by microorganisms such as Bacillus and Streptomyces can be used. Various commercial products such as Alcalase (Novo), Actinase (Kaken Pharmaceutical Co., Ltd.), and Proleather (Ohno Pharmaceutical Co., Ltd.) are particularly preferred6.Also, alkaline proteases other than those of microbial origin can also be used. Acidic proteases and neutral proteases are undesirable because they reduce the recovery rate of hydrolysates, tend to generate free amino acids, and increase flavor. The amount of protease used is preferably 0.05 to 10% by weight based on protein, but depending on its potency, the amount used is not limited to this and may be used in a wider range of amounts.

The reaction temperature during hydrolysis is preferably 30 to 70°C, which is the optimum temperature for protease. If it is below 30°C, hydrolysis by protease will be difficult to proceed, and if it is above 70°C, the resulting hydrolyzate will have a fishy odor. becomes stronger and has a negative impact on quality. When fish protein is subjected to alkaline protease-killing action and hydrolysis is started, the pH decreases, so the optimum pH for the enzyme, pH 7.5 to 9.0, must be constantly maintained during the reaction.

In the present invention, the degree of hydrolysis performed by causing alkaline protease to act on fish protein is controlled to be in the range of 15 to 25%. Here, the degree of hydrolysis (DH
) is a numerical value representing the degree of hydrolysis expressed as a percentage of the number of cleaved peptide bonds divided by the total number of peptide bonds.For details, see [J.

Agric, Food Chem, J vol, 24
．． Na6, 1976, pages 1090 to 1093.

Hereinafter, in this specification, the degree of hydrolysis will be abbreviated as DH, but D
When DH is less than 15%, the recovery rate of the hydrolyzate is low, and tryptophan remains in the insoluble category, lowering the amino acid score of the hydrolyzate in the water-soluble category and lowering its nutritional value. If it exceeds 25%, relatively bitter di- or tripeptides with a molecular weight of 500 or less will increase, free amino acids will increase, and the flavor will become stronger, which is not desirable in terms of quality.

Next, the reaction time during hydrolysis is basically 15% of DH.
It is an arbitrary period of time that is 25% or less, but usually 2 to 4
It is desirable to complete the reaction in 8 hours, preferably 3 to 24 hours. If the reaction time is less than 2 hours.

The recovery rate of hydrolyzate is low and the amino acid score is also low.

On the other hand, if the time is longer than 48 hours, the odor of the hydrolyzate becomes extremely bad, which is not desirable in terms of quality.

Next, the reaction mixture obtained by the above hydrolysis reaction is heated to 80 to 100°C for about 10 minutes, or an organic or inorganic acid is added to the reaction mixture to adjust the pH to 4.
After completely inactivating the protease by stirring at 45-60°C for 30 minutes, the insoluble fraction is removed by centrifugation or filtration to obtain a fish protein hydrolyzate as a clear solution. In addition, in the treatment of the reaction mixture, it is also possible to obtain a clarified portion by centrifugation or filtration before inactivating the protease, and then separate and remove the contaminating protease using an ultrafiltration membrane. If so, the recovered protease can also be used for new hydrolysis.

The hydrolyzate thus obtained is then finished using known techniques, ie, purified, concentrated, desalted, sterilized, and dried to obtain the desired hydrolyzate.

That is, in the treatment of the hydrolyzate, the purification process can be deodorized and decolorized by treatment with an adsorbent such as activated carbon, silica gel, activated clay, etc., and the concentration process can be mainly reverse osmosis, vacuum distillation, etc. , methods such as thin film distillation, as a desalination process.

Methods such as dialysis, electrodialysis, reverse osmosis, etc. are used for the sterilization process, methods such as pasteurization, heat sterilization, and filtration sterilization are used for the sterilization process, and methods such as spray drying and freeze drying are used for the drying process.
The desired hydrolyzate can be obtained.6Furthermore, it is possible to omit all or some of these steps other than sterilization depending on the use of the product, and even if omitted, there will be no impact on quality. A problem-free hydrolyzate is obtained. The pH of the hydrolyzed solution obtained in the present invention before the finishing step is usually in the range of pH 3.0 to 9.0, but this pH may vary depending on the use of the product. The pH value can be changed at any time before or during the finishing process.

The fish protein hydrolyzate of the present invention obtained as described above has the following properties.

(1) The content of peptides having a molecular weight of 5,000 or more is 15% by weight or less, preferably 10% by weight or less.

(2) The content of peptides with a molecular weight of 500 or less is 40% by weight or less, preferably 30% by weight or less.

(3) The amount of free amino acids is 10% by weight or less, preferably 5% by weight.
% by weight or less.

(4) Amino acid score is 70 or more, preferably 80 or more.

In addition, the amino acid score referred to in this specification is calculated based on the standard value of FAO/no (1973) according to the amino acid composition in the hydrolyzate, and the value of tryptophan, which is the first limiting amino acid, is used as the amino acid score. . in this case,
The standard values of FAO/W) 10 (1973) are shown below.

In addition, the amino acid score is expressed as , and is an evaluation standard commonly used to judge the nutritional value of protein.

The closer this value is to 100, the more ideal the protein is with good nutritional value; however, in practice, if it is 70 or higher, preferably 80 or higher, it is usually considered to be a protein with good nutritional value. be done. Incidentally, this fish protein hydrolyzate can be said to be an excellent protein material from a nutritional standpoint, compared to the amino acid score of vegetable proteins such as soybean protein, which are currently widely used as food materials, and have a rather low amino acid score of 60 to 70.

〔effect〕

The fish protein hydrolyzate of the present invention has a good amino acid score, has little fishy odor, and has little unpleasant taste such as bitterness and umami, and can be used for food in various forms such as solution and powder. It is advantageously used as a protein material.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that the percentages shown below are based on weight unless otherwise specified, and the evaluation method for the hydrolyzate is as follows.

(1) Recovery rate of hydrolyzate Nitrogen analysis was performed using the microkersol method.

(2) Amino acid composition Except for tryptophan and cystine, the sample was hydrolyzed with 6N hydrochloric acid at 110° C. for 24 hours, and then measured by an automatic amino acid analysis method. Tryptophan was hydrolyzed with barium hydroxide at 100°C for 12 hours and then measured by high performance liquid chromatography, and cystine was measured by performic acid oxidation.

(3) Quantification of free amino acids The hydrolyzate was directly measured without pretreatment according to the amino acid composition analysis method described in section (2) above, and the total amount of individual amino acids was determined as the amount of free amino acids.

(4) Fractional determination of peptides Using Sephadex G25, the elution positions of molecular weights 5000 and 500 were determined from the relationship between elution position and molecular weight based on gel chromatography of standard peptides with known molecular weights.

The hydrolyzate was then subjected to gel chromatography under the same conditions, and fractions with a molecular weight of 5,000 or more and a fraction with a molecular weight of 500 or less were collected. Furthermore, the amount of nitrogen in each section was measured by the Kjeldahl decomposition method, and divided by the amount of nitrogen in the entire sample to calculate the amount of peptides with a molecular weight of 5000 or more and 500 or less.

Note that depending on the low-molecular-weight peptide or amino acid, there may be a slight deviation in the elution position, but here, using the method described above,
The peptide amount was set to have a molecular weight of 5000 or more and 500 or less.

Example 1 Acidified 8% suspension of sardine fish meal.

Hydrolysis treatment was carried out using neutral and alkaline proteases under conditions where the amount of protease added (to protein) was 10% and the reaction time was 6 hours. The results are shown in Table-1.

The raw materials for producing the protease shown below are as follows.

(1) Acidic protease pepsin (manufactured by Tokyo Kasei Kogyo Co., Ltd.): Porcine gastric juice neurase (manufactured by Jinko Pharmaceutical Co., Ltd.): Rhizopus morsin (manufactured by Seiun Pharmaceutical Co., Ltd.): Aspergillus 5aitoi (2) Neutral protease Neurose (manufactured by Novo): Bacillus subtilis papain (manufactured by Merck & Co.): Papaya pancreatin (manufactured by Jinko Pharmaceutical): Pig pancreas (3) alkaline protease alcalase (manufactured by Novo): To Bacillus subtilis Bacillus licheniformis Proleather (manufactured by Jinko Pharmaceutical Co., Ltd.): Bacillus subtilis (Bacillus 5ubtilis) Actinase (manufactured by Kaken Pharmaceutical Co., Ltd.): Streptomyces griseus (Streptomyces griseus);
The color tone, bitterness, and flavor shown in Table 1 and below were evaluated by six experts using a hydrolyzed solution with a protein concentration of 5%.

The evaluation criteria are as follows.

10...Bad (unsuitable as a food material)±...
・Slightly bad (can be used as a food material) ---
Good (very good as a food material) Table 1 As is clear from Table 1, when fish protein is hydrolyzed with acid protease, the recovery rate of the hydrolyzate is low, the amino acid score is poor, and the taste is poor, such as bitterness and umami. An unpleasant taste is also observed. Furthermore, although neutral protease does not have an unpleasant taste, the recovery rate of the hydrolyzate is clearly low and the amino acid score is also poor.

On the other hand, when hydrolyzed with alkaline protease, the recovery rate of the hydrolyzate is improved, the amino acid score is also good, and there are few unpleasant tastes such as bitterness and umami.

Therefore, it can be seen that when fish protein is hydrolyzed with protease, alkaline protease has a remarkable effect, giving good results in terms of recovery rate, amino acid score, bitterness, and flavor.

Example 2 An experiment was conducted in the same manner as in Example 1, except that alkaline protease (alcalase) was used, the amount of protease added (relative to protein) and the reaction time were varied, and the degree of hydrolysis (DH) was varied. Ta. Table the results.
Shown in 2.

As is clear from Table 2, when the DH is less than 15%, the recovery rate of the hydrolyzate is low, tryptophan becomes the first limiting amino acid, the amino acid score is low, and it is unfavorable from an economical and nutritional standpoint. .

On the other hand, when DH exceeds 25%, peptides with a molecular weight of 500 or less, which greatly affect bitterness, will account for 40% or more, and free amino acids that have umami will also exceed 103, which may be undesirable in terms of bitterness and umami. Recognize.

Therefore, if DH is in the range of 15% or more and 25% or less.

A hydrolyzate with good recovery rate and amino acid score, low bitterness, low flavor, and good color tone with little fishy odor can be obtained.

Example 3 Sardine fishmeal (shredded sardines steamed, pressed, dried, and crushed) was defatted with hexane, dried, and used as a protein source.

First, 895 g of water was added to 102 g of the above protein source (78.6% protein content, containing 80 g of protein), the whole system was heated to 55°C with stirring, and 3.6 mjl of 4N-NaOH was added to adjust the pH to 8. Adjusted to 0.

Next, 1.6 g of Alcalase was added and the DH was reduced to 1 at 55°C.
4N, keeping the pH constantly at 8.0 until it reaches 5%.
・Hydrolysis while adding -NaOH (4N -NaOH
After use amount of 20IIIQ, reaction time of about 6 hours), 4n-
75 g of HCQ was added, the pH was adjusted to 4.0, and the mixture was stirred at 55° C. for 30 minutes to inactivate alcalase.

Next, the 9 reaction solutions were centrifuged at a centrifugal acceleration of 3000 x g for 15 minutes to obtain a transparent supernatant (1) weighing 920 g. Add 900 g of water to the residue after centrifugation, stir and mix thoroughly, and centrifuge again to obtain 930 g of supernatant (I[). A transparent hydrolyzed solution of Og was obtained.

Add 81.3 g of 30%-NaO to this hydrolyzed solution,
After adjusting the pH to 7.0 and separating the resulting precipitate by filtration, 1.0 g of activated carbon was added to the filtrate and stirred at 50°C for 30 minutes to deodorize and decolorize.The activated carbon was removed and the sardine protein hydrolyzate 1750
I got g.

This solution was sterilized by heating at 100°C for 5 minutes, and then spray-dried using a laboratory spray dryer to produce a white fine powder of 66.
．． 5g was obtained.

The obtained hydrolyzate has little fishy odor and unpleasant taste such as bitterness and umami, and has a protein content of 71.0%.
The recovery rate was 59.0%, the amount of peptides with a molecular weight of 5000 or more was 9.3%, and the amount of peptides with a molecular weight of 500 or less was 20.
6%, free amino acid content 2.8%, amino acid score 8
It was 2.

Next, 15 g of sugar, 3 g of citric acid, 0.5 g of sodium citrate, 0.5 g of vitamin C, powdered fruit essence, and trace amounts of coloring were added to this powder Log and thoroughly mixed to obtain a fruit-type powdered beverage product. When this product was dissolved in about 10 times the amount of water, a clear, acidic (p) 13.5), delicious and nutritious beverage was obtained.

Example 4 The sardine fishmeal used in Example 3 was washed twice with 5 times the amount of water (stirred at 20-25°C for 30 minutes) and dried, which was used as a protein source.

First, 20.5 kg of the above protein source (protein content 78.1%)
, containing 16 kg of protein) was added with 180 kg of wood, and the whole system was heated to 60° C. while stirring, and 1Ω of 4N-NaOH was added to adjust pn to 8.0.

Next, 1.3 kg of Alcalase was added, and D was heated at 60°C.
Hydrolysis (4N-NaOH) was carried out while constantly adding 4N-NaOH so that the PR was 8.0 until the H content reached 20%.
OH usage amount: 5.2Q, reaction time: approximately 5 hours), 4N-
12.5 kg of HCfl was added, pi was adjusted to 4.0, and the mixture was stirred at 55° C. for 30 minutes to inactivate alcalase.

Next, the reaction solution is treated with a decanter type centrifuge to first remove bones, scales, etc. with large particle sizes, and then insoluble proteins with small particle sizes are removed with a solid eject type centrifuge. 165 kg of clear liquid was obtained. 150 kg of water is added to the cake discharged from the centrifugal milk
After stirring and mixing, the mixture was processed again using the same centrifugal separator, and combined with the previous centrifuged liquid, a total of 310 kg of hydrolyzed liquid was obtained.

Add 150g of activated carbon to this hydrolyzed solution and heat at 50℃ for 3 hours.
After stirring for 0 minutes, activated carbon was removed using a filter press, and 200 g of 30% Nail was added to the obtained filtrate.
The resulting precipitate was removed using a filter press to obtain 290 kg of a transparent sardine hydrolyzate.

Next, apply this solution to a reverse osmosis machine (temperature 20°C, pressure 30kg).
/dt) to desalt and concentrate to 30 kg, and the concentrated liquid was
Heat sterilize at 00°C for 5 minutes, then use a spray dryer (inlet temperature 250-260°C, outlet temperature 150-160°C).
Spray-dried at 0°C) to give pale yellowish brown fine powder 11,5
I got kg.

The protein content of the obtained hydrolyzate was 91.3%, the recovery rate was 65.6%, and the amount of peptides with a molecular weight of 5,000 or more was 7.
The amount of peptides with a molecular weight of 500 or less was 24.0%, the amount of free amino acids was 3.6%, and the amino acid score was 91, with less unpleasant taste and less fishy odor.

Next, add 65g of sugar, 15g of honey to this powder Log,
Add 13g of lemon juice, 12g of gelatin, 2g of citric acid, 0.5g of vitamin C, lemon essence, and a small amount of coloring agent, mix well, add 250ml of hot water to dissolve, then add 100ml of cold water, and stir for 1 hour. By cooling at ℃, a transparent jelly that did not lose its shape and had a good taste was obtained.

Example 5 Codfish meal (shredded cod is steamed, pressed, dried and pulverized) was defatted with hexane, dried, and used as a protein source.

First, 176 g of the above protein source (protein content 68.5%,
570 g of water was added to the mixture (containing 120 g of protein), and while stirring, the whole system was heated to 40° C., and 6 mfl of 4N-NaOH was added to adjust p)l to 8.5.

Next, 4.8 g of actinase was added and the DH was reduced to 2 at 40°C.
4N, keeping the pH constantly at 8.5 until it reaches 5%.
After hydrolysis while adding -NaOH (amount of 4N-NaOH used: 5Ω, reaction time: about 12 hours), the entire system was heated to 90°C and left for 10 minutes to inactivate actinase.

Further, the entire system was rapidly cooled to 50°C, and the pH was adjusted to 7.0 by adding 24 g of 4N-IC°C, and then the entire system was filtered and the cake was washed with water to obtain 1670 g of a filtrate.

Add 50g of silica gel to this hydrolyzed solution and wait for 30 minutes.
After stirring at 50°C, filter the transparent cod hydrolyzate 160
0 g was obtained.

This solution was heat sterilized at 100°C for 5 minutes, and then heated at 65°C in a laboratory vacuum concentrator (40-50°C, 1-2 mmHg).
It was concentrated to 0 g and freeze-dried to obtain 107 g of cod protein hydrolyzate as a white powder.

The obtained hydrolyzate has less fishy odor and less unpleasant taste, the protein content is 79.7%, the recovery rate is 71.2%, and the amount of peptides with a molecular weight of 5000 or more is 6.4.
%, the amount of peptides with a molecular weight of 500 or less was 27.0%, the amount of free amino acids was 4.3%, and the amino acid score was 97.

Next, 60 g of wheat flour, 10 g of water, 5 g of edible oil, 13 g of sugar, 0.5 g of salt, 0.4 g of baking soda, 0.4 g of ammonium carbonate, and a small amount of flavoring were added to 5 g of this powder and thoroughly stirred and mixed to form a paste. By heating for 180'Cl2O, a texture and delicious taste was obtained.

Example 6 Fish meat with bones and scales removed from raw sardines was collected, cut into small pieces, washed with water, further steamed, pressed, dried, defatted and dried, and used as a protein source.

First, the above protein source 1167 g (protein content 85.7
%, containing 1000 g of protein), added 3830 g of water, heated the whole system to 65°C with stirring, and heated it to 4N-N.
The pH was adjusted to 7.5 by adding aOH40mQ.

Next, add 1 g of Proleather and 4N-N at 65℃ until the pH becomes 7.5 until D)I becomes 18%.
After hydrolysis while adding aOH (amount of 4N-NaOH used: 300 m Q, reaction time: about 24 hours), 1500 g of 30% citric acid was added, the pH was adjusted to 4.0, and the mixture was heated at 10°C.
The mixture was stirred for 30 minutes to inactivate Proleather.

Next, the reaction solution was treated with a basket-type centrifugal filter, and
00 g of filtrate was obtained. Furthermore, centrifugal filtration was continued while gradually pouring 1.5 kg of water into the cake remaining in the basket, and finally 6.5 kg of filtrate was obtained.

Activated carbon Log was added to this filtrate, and after stirring at 60° C. for 15 minutes, the mixture was filtered to obtain 6.4 kg of a transparent sardine hydrolyzate.

This solution was heat sterilized at 80°C for 30 minutes, and then the pH
4.0 was spray-dried using a spray dryer to obtain 778 g of white fine powder.

The protein content of the obtained hydrolyzate was 83.2%, the recovery rate was 64.7%, and the amount of peptides with a molecular weight of 5000 or more was 8.2%.
The amount of peptides with a molecular weight of 500 or less was 23.5%, the amount of free amino acids was 3.0%, and the amino acid score was 86, indicating that the hydrolyzate had little fishy odor and less unpleasant taste.

Next, to 20 g of this powder, 0.3 g of sweetener (aspartame: manufactured by Ajinomoto Co., Ltd.), 0.2 g of sodium citrate, 0.2 g of vitamin C, natural fruit juice, and trace amounts of natural coloring are added and thoroughly mixed to make a fruit-type powdered drink. It was made into a product.

When this product is dissolved in approximately 15 times the amount of water, it becomes acidic (pH 4,
0), a clear beverage with excellent taste was obtained.

Example 7 Using minced cod as a protein source, 750 g of water was added to 44 g (protein content: 90.9%, protein content: 40 g), the whole system was heated to 50° C. with stirring, and 4N-Na
1.5 ml of OH was added to adjust the pH to 8.0.

Bioplase 5plo (manufactured by Nagase Seikagaku Kogyo Co., Ltd., trade name), an alkaline protease originating from Bacillus spp.
Add 2g and adjust the pH at 50℃ until D)I becomes 23%.
Hydrolyze while standing so that it becomes 8.0 without any fluctuation (4N -NaOH required amount 13 friends Q time 2 hours)
Thereafter, 65 g of 25% malic acid was added, the pH was adjusted to 4.0, and the mixture was stirred at 50° C. for 15 minutes to inactivate bioplase.

The reaction solution was centrifuged at a centrifugal acceleration of 300 x g for 10 minutes to obtain a 900 g clear supernatant. Further, 400 g of water was added to the residue after centrifugation, thoroughly stirred and mixed, and centrifuged again to obtain 1280 g of a transparent hydrolyzed liquid together with the supernatant.

51 g of activated clay was added to this solution, and the mixture was stirred at 50°C for 1 hour to deodorize and decolorize. After the adsorbent was filtered off, a membrane filter (manufactured by Toyo Seishi Co., Ltd., TM-4, pore size 0.2
sterilized by filtration using 11μm) and transparent cod hydrolyzate 11
Obtained 50g. The obtained hydrolyzed solution had little fishy odor and unpleasant taste such as bitterness and umami, and its protein content was 2.4% and the recovery rate was 69.0%. A portion of this hydrolyzed solution was freeze-dried and its properties were investigated. The protein content was 71.4%, the amount of peptides with a molecular weight of 5000 or more was 6.7%, and the amount of peptides with a molecular weight of 500 or less was 2.
The amount of free amino acids was 4.1%, and the amino acid score was 96.

Next, add 35g of sugar and 15g of honey to 1Ω of this hydrolyzed solution.
After adding 0.5 g of sodium malate, 0.5 g of vitamin C, cola essence and a small amount of coloring agent and stirring thoroughly, sterilization was carried out at 105°C for 3 seconds, and by filling with carbon dioxide gas, a cola type product was created. A beverage with excellent taste was obtained.

Claims (2)

[Claims] (1) A water-soluble hydrolyzate of fish protein with a molecular weight of 5
000 or more peptide content is 15% by weight or less, molecular weight 5
A fish protein hydrolyzate characterized in that the content of peptides of 00 or less is 40% by weight or less, the amount of free amino acids is 10% by weight or less, and the amino acid score is 70 or more. (2) Hydrolyze fish protein dispersed in an aqueous medium with alkaline protease under alkaline conditions to achieve a molecular weight of 5000.
It is characterized by producing a water-soluble hydrolyzate having a content of the above peptides of 15% by weight or less, a content of peptides with a molecular weight of 500 or less of 40% by weight or less, an amount of free amino acids of 10% by weight or less, and an amino acid score of 70 or more. A method for producing a fish protein hydrolyzate.