CN105192665B - One seed shrimp liquid flavor and preparation method and application - Google Patents

Abstract

The invention discloses a shrimp flavor liquid and its preparation method and application. The preparation method comprises the following steps: 1) preparing shrimp head enzymatic hydrolysis solution: mixing and pulverizing shrimp heads and water to obtain shrimp head crushing liquid; then mixing the shrimp head crushing liquid and protease for enzymolysis to obtain shrimp head enzyme solution; 2) preparing shrimp flavor liquid: mixing reducing sugar, amino acid and the shrimp head enzymolysis liquid to carry out Maillard reaction to obtain shrimp flavor liquid. The preparation method is simple and feasible, and the product quality can basically meet the requirements of similar products. The method of enzymatic hydrolysis coupled with Maillard reaction is adopted to obtain the shrimp flavor liquid with good color, rich nutrition and strong shrimp flavor. On the one hand, it can make full use of precious resources such as shrimp heads and turn waste into treasure; on the other hand, it can also solve the problem of environmental pollution caused by shrimp heads. It can be used as a food flavor additive, opening up a new way for the comprehensive utilization of shrimp heads. For example, as an important ingredient in instant noodles, meat processing and other fields, the market prospect is very broad.

Description

A kind of shrimp flavor liquid and its preparation method and application

technical field

The invention belongs to the technical field of food processing, and in particular relates to a shrimp flavor liquid and its preparation method and application.

Background technique

In recent years, countries around the world have continuously developed the shrimp farming industry, which has made great contributions to global economic development, food supply, food security, employment and poverty alleviation. The output of Penaeus vannamei in China ranks first in the world. Penaeus vannamei, scientifically known as Penaeus vannamei, is one of the three largest species of farmed shrimp in the world. It is native to Central and South America The waters along the Pacific coast of China have become the main cultured shrimp in my country. Prawns are not only nutritious, delicious, and cheap, but also have health care functions for the human body, and have always been favored by consumers. Studies by Wang Lingyan and others have shown that the water content of prawns is high, and they are easily spoiled and deteriorated under natural conditions, making it difficult to store and transport, resulting in loss of nutritional value of prawns and waste of resources. Therefore, in order to effectively utilize this marine biological resource, it is necessary to process the freshly harvested shrimp. my country’s export of prawns is mainly head-off shrimp, and a large number of shrimp heads will be produced during the processing of prawns. ton meter. At present, due to the lag of processing technology, only a small part of this part of resources is processed into animal feed and used to extract astaxanthin, chitin, amino acids, etc., and most of them are discarded as garbage, which not only causes extreme waste of resources. The huge waste also brings serious pollution to the environment and affects the lives of local residents.

According to reports, in the Chinese food industry, flavoring condiments are still new products with a development history of less than 30 years. And the research method of existing condiment at home and abroad is mainly divided into three kinds, the first one is made by spices, natural spices and synthetic spices; Spices, natural flavors and synthetic flavors; the third is based on the thermal reaction products of hydrolyzed animal and vegetable proteins, and spices, natural flavors and synthetic flavors are added.

Contents of the invention

The object of the present invention is to provide a kind of shrimp flavor liquid and its preparation method.

The preparation method provided by the present invention comprises the following steps:

1) Preparation of shrimp head enzymatic hydrolysis liquid: mixing and pulverizing shrimp heads and water to obtain shrimp head crushing liquid; then mixing the shrimp head crushing liquid and protease for enzymolysis to obtain shrimp head enzymatic hydrolysis liquid;

2) Preparation of shrimp flavor liquid: mixing reducing sugar, amino acid and shrimp head enzymolysis liquid described in step 1) to carry out Maillard reaction to obtain shrimp flavor liquid.

In the above-mentioned preparation method, in step 1), the shrimp head is specifically the shrimp head of Penaeus vannamei, and the head and chest of the shrimp head of Penaeus vannamei are collectively referred to as the head, as can be seen from the internal structure and external form of Penaeus vannamei, The shrimp head concentrates most of the organs in the vannamei, accounting for about 1/3 of the whole shrimp in terms of body length and weight.

The mass ratio of the shrimp head to water is 1:(1-2), specifically 1:1.

In order to better mix with water, before using the shrimp heads, take out the frozen preserved shrimp heads and thaw them out, and then pound them with a mortar.

The crushing can be carried out in a beater, and the particle size of the crushing is specifically 120-180 μm.

The protease is a composite protease (model is Protamex), enzyme activity 1.04 × 105U/g, flavor protease (model is Flavourzyme 500MG), enzyme activity 1.5AU/g, hydrolytic protease (model is Alcalase2.4L FG), enzyme activity 0.6 AU/g or neutral protease (Neutrase model), enzyme activity 0.5AU/g, were purchased from Novozymes (China) Biotechnology Co., Ltd.

The added amount of the protease is 0.5%-1.5% of the mass of the crushed shrimp head liquid.

The conditions of the enzymolysis are as follows: the enzymolysis temperature is 40-60° C., the enzymolysis time is 2-6 hours, and the enzymolysis pH is 6.5-7.5.

When the protease is a composite protease, the added amount of the composite protease is 0.5%-1.5% of the mass of the crushed shrimp head liquid, preferably 1.4%.

The enzymolysis conditions are as follows: enzymolysis temperature is 50-60°C, enzymolysis time is 2-4h, enzymolysis pH is 7.0-7.5, preferably enzymolysis temperature is 60°C, enzymolysis time is 3h, enzymolysis The pH is 7.4.

When the protease is a flavor protease, the added amount of the flavor protease is 0.5%-1.5%, preferably 0.8%, of the mass of the crushed shrimp head liquid.

The enzymolysis conditions are as follows: enzymolysis temperature is 40-60°C, enzymolysis time is 3-5h, enzymolysis pH is 6.5-7.0, preferably enzymolysis temperature is 50°C, enzymolysis time is 4h, enzymolysis The pH is 6.6.

When the protease is a hydrolytic protease, the added amount of the hydrolytic protease is 0.5%-1.0%, preferably 0.8%, of the mass of the crushed shrimp head liquid.

The enzymolysis conditions are as follows: enzymolysis temperature is 40-60°C, enzymolysis time is 3-5h, enzymolysis pH is 6.5-7.5, preferably enzymolysis temperature is 60°C, enzymolysis time is 4h, enzymolysis The pH is 7.0.

When the protease is a neutral protease, the added amount of the neutral protease is 0.5%-1.5% of the mass of the crushed shrimp head liquid, preferably 1.4%.

The enzymolysis conditions are as follows: enzymolysis temperature is 40-60°C, enzymolysis time is 2-6h, enzymolysis pH is 6.5-7.5, preferably enzymolysis temperature is 60°C, enzymolysis time is 3h, enzymolysis The pH is 7.2.

In the above preparation method, step 1) also includes the step of further purifying the enzymatic hydrolyzate of shrimp head: inactivating the enzymatic hydrolyzate of shrimp head at 95-105°C for 5-15min; then centrifuging to obtain the supernatant solution, and the supernatant was filtered to obtain the purified shrimp head enzymolysis solution.

In the above preparation method, in step 2), the reducing sugar is selected from monosaccharides and/or disaccharides, the monosaccharides can be selected from pentoses or hexoses, and the pentoses can be selected from ribose, arabinose or Xylose, the hexose is specifically selected from galactose, mannose or glucose; the disaccharide is specifically selected from maltose, lactose or sucrose.

The reducing sugar is further selected from at least one of glucose, xylose, sucrose and ribose, preferably glucose and/or xylose, most preferably with a mass ratio of 1:(2-5) (eg: 1:4) A mixed sugar of xylose and glucose.

The amino acid is selected from at least one of cystine, cysteine, arginine, glycine, alanine, proline, aspartic acid and glutamic acid, specifically selected from cystine, glycine At least one of , alanine and arginine, preferably a mixed amino acid of glycine and arginine with a mass ratio of 1:(0.5-3) (eg: 1:1).

The mass ratio of the reducing sugar, the amino acid and the shrimp head enzymolysis solution in step 1) is (2-6): (1-5): 100, specifically (2-4): (2- 4): 100, preferably 4:2:100.

The conditions of the Maillard reaction are as follows: the reaction temperature is 80-120°C, the reaction time is 20-60min, the pH of the reaction system is 4-8, and the reaction temperature is 100-120°C, and the reaction time is 40-60min , The pH of the reaction system is 6-8, preferably the reaction temperature is 100°C, the reaction time is 50min, and the pH of the reaction system is 8.

In the above preparation method, in step 2), the optimal preparation conditions of the shrimp flavor liquid are as follows:

The reducing sugar is a mixed sugar of xylose and glucose with a mass ratio of 1:4

The amino acid is a mixed amino acid of glycine and arginine with a mass ratio of 1:1.

The mass ratio of the reducing sugar, the amino acid and the shrimp head enzymatic hydrolyzate in step 1) is 4:2:100.

The reaction temperature of the Maillard reaction is 100° C., the reaction time is 50 minutes, and the pH of the reaction system is 8.

Another object of the present invention is to provide the shrimp flavor liquid obtained by the above preparation method.

In addition, the present invention also provides the shrimp head enzymatic hydrolyzate obtained in the above preparation method.

The application of the shrimp flavor liquid and/or shrimp head enzymolysis liquid prepared by the above preparation method of the present invention in the preparation of food flavor additives also belongs to the protection scope of the present invention.

The present invention uses shrimp head as raw material, adopts the method of enzymatic hydrolysis coupling Maillard reaction, the preparation method is simple and feasible, the product quality can basically meet the requirements of similar products, and the shrimp with good color, rich nutrition and strong shrimp flavor is obtained Flavored liquid. On the one hand, it can make full use of precious resources such as shrimp heads, turn waste into treasure, and generate economic value; on the other hand, it can also solve the problem of environmental pollution caused by shrimp heads. It has opened up a new way for the comprehensive utilization of shrimp heads. For example, as an important ingredient in the fields of instant noodles and meat processing, the market prospect is very broad.

Detailed ways

The experimental methods used in the following examples are conventional methods unless otherwise specified.

The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

Materials and reagents used in each of the following examples are as follows:

Shrimp head of Penaeus vannamei, Zhaofeng Aquatic Food Co., Ltd.; formaldehyde (37.0%～40.0%): analytically pure, Guangzhou Chemical Reagent Factory; sodium hydroxide: analytically pure, Guangzhou Chemical Reagent Factory; enzyme preparation: enzyme preparation selected for the test See Table 1 below:

Table 1. Enzyme preparations used in the test

Glucose, biochemical reagent grade, Sinopharm Chemical Reagent Co., Ltd.; sucrose, biochemical reagent grade, Xilong Chemical Factory, Shantou, Guangdong; D-ribose, biochemical reagent grade, Shanghai Yuanye Biotechnology Co., Ltd.; D-(+)-wood Sugar, biochemical reagent grade, Sinopharm Chemical Reagent Co., Ltd.; glycine, biochemical reagent grade, Shanghai Boao Biotechnology Co., Ltd.; L-arginine, biochemical reagent grade, Shanghai Yuanye Biotechnology Co., Ltd.; L-alanine , biochemical reagent grade, Shanghai Yuanye Biotechnology Co., Ltd.; L-partic acid, biochemical reagent grade, Shanghai Yuanye Biotechnology Co., Ltd.; L-cystine, biochemical reagent grade, Shanghai Yuanye Biotechnology Co., Ltd.; L -Proline, biochemical reagent grade, Sinopharm Chemical Reagent Co., Ltd.; L-glutamic acid, biochemical reagent grade, Sinopharm Chemical Reagent Co., Ltd.; L-cysteine, biochemical reagent grade, Aladdin Industrial Company.

The instruments used in the following examples are as follows: SQ2121 multifunctional food processor: Shanghai Shuaijia Electronic Technology Co., Ltd.; digital constant temperature water bath: HH-4, Changzhou Aohua Instrument Co., Ltd.; pH meter: PHS-3C type , Shanghai Precision Scientific Instrument Co., Ltd.; electronic balance: PL303, Mettler-Toledo Instrument (Shanghai) Co., Ltd.; desktop centrifuge: MGLD4-2A, Beijing Zhongxi Yuanda Technology Co., Ltd.; circulating water vacuum pump: SHZ-D9( III), Gongyi Yuhua Instrument Co., Ltd.; beater, model SQ2121, Shanghai Shuaijia Electronic Technology Co., Ltd.; centrifuge, model D-37520, ThermoElectron LED GmbH;

Embodiment 1, preparation shrimp flavor liquid:

1. Preparation of shrimp head enzymatic hydrolysis solution:

The protein content of the sample was determined by micro Kjeldahl method, referring to GB/T5009.5-2010; the determination of amino acid nitrogen was by ZBX66038-87 formaldehyde potentiometric titration method; the amino acid composition of different protein hydrolyzate was determined by reference to GB/T18246-2000 .

1) Enzymatic hydrolysis process: shrimp head of Penaeus vannamei→weighing→beating (solid-liquid mass ratio 1:1) to obtain shrimp head crushing liquid→adjusting pH value→adding enzyme→constant temperature water bath for oscillating enzymolysis→passivating enzyme (boiling water bath 10min)→enzymolysis solution→centrifugation→take the supernatant and filter→determination of amino acid nitrogen;

The optimization of the specific enzymatic hydrolysis process is as follows:

The effect of the amount of enzyme added on the content of amino nitrogen: with the selected enzyme, the amount of enzyme added is respectively 0.6%, 0.8%, 1.0%, 1.2%, and 1.4% of the mass of the shrimp head crushed liquid, and the enzymolysis reaction is carried out to determine Amino nitrogen content, to determine the optimal amount of enzyme.

The effect of enzymatic hydrolysis pH value on amino nitrogen content: the enzymatic hydrolysis pH values are 6.6, 6.8, 7.0, 7.2, 7.4 respectively, and the enzymatic hydrolysis reaction is carried out under the determined conditions, and the amino nitrogen content is determined to determine the best enzyme Solution pH.

The effect of enzymatic hydrolysis temperature on the content of amino nitrogen: the temperature is 40, 45, 50, 55, and 60°C respectively, and the enzymatic hydrolysis reaction is carried out under the determined conditions, the content of amino nitrogen is determined, and the optimal enzymatic hydrolysis temperature is determined.

The effect of enzymatic hydrolysis time on the content of amino nitrogen: Under the determined conditions, the enzymatic hydrolysis time is 2, 3, 4, 5, and 6 hours respectively, and the enzymatic hydrolysis reaction is carried out to measure the content of amino nitrogen and determine the best enzymatic hydrolysis time .

2) Results and discussion:

a) The protein content of the shrimp head of Penaeus vannamei was measured to be 14.47% by micro Kjeldahl method.

b) Effects of different enzymes on the head of Penaeus vannamei on the content of amino nitrogen:

b-1) Effect of compound protease on amino nitrogen content:

b-1-1) Effects of different enzyme dosages on amino nitrogen content: 150g of each head of Penaeus vannamei, enzymolysis temperature 50°C, enzymolysis time 4h, pH 7.0, adding different amounts of compound protease for hydrolysis , the obtained content of amino nitrogen is shown in Table 2.

Table 2, the relationship between different amounts of compound protease and amino nitrogen content

It can be seen from Table 2 that before the amount of enzyme added reaches 1.4%, the enzymolysis effects under various enzyme amounts are similar, and when the amount of enzyme added is 1.4%, the effect of enzymolysis is significantly higher than that of other enzyme amounts. Therefore, under the same other conditions, when the enzyme dosage is 1.4%, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-1-2) The effect of different enzymatic hydrolysis pH on amino nitrogen content: 150g of each shrimp head of Penaeus vannamei, the enzyme dosage is 1.4%, the enzymatic hydrolysis temperature is 50°C, and the enzymatic hydrolysis time is 4h. The obtained content of amino nitrogen is shown in Table 3.

Table 3, the relationship between different enzymatic hydrolysis pH and amino nitrogen content

It can be seen from Table 3 that the amino nitrogen content gradually increased with the increase of the pH of the enzymatic hydrolysis. Therefore, under the same other conditions, when the enzymatic hydrolysis pH is 7.4, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-1-3) Effects of different enzymatic hydrolysis temperatures on amino nitrogen content: 150g of shrimp head for each sample, 1.4% enzyme dosage, 4h enzymolysis time, pH7.4, using different enzymolysis temperatures for hydrolysis, the obtained The content of amino nitrogen is shown in Table 4.

Table 4, the relationship between different enzymatic hydrolysis temperatures and amino nitrogen content

It can be seen from Table 4 that before the enzymatic hydrolysis temperature reaches 60°C, the enzymatic hydrolysis effects at various enzymatic hydrolysis temperatures are similar, and when the enzymatic hydrolysis temperature is 60°C, the enzymatic hydrolysis effects are significantly higher than those at other enzymatic hydrolysis temperatures. Therefore, under the same other conditions, when the enzymatic hydrolysis temperature is 60°C, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-1-4) Effect of different enzymolysis time on amino nitrogen content: 150g of each sample shrimp head, enzyme dosage 1.4%, enzymolysis temperature 60 ℃, pH7.4, adopt different enzymolysis time to carry out hydrolysis, so The obtained content of amino nitrogen is shown in Table 5.

Table 5, the relationship between different enzymatic hydrolysis time and amino nitrogen content

It can be seen from Table 5 that when the enzymatic hydrolysis time is less than 3 hours, the amino nitrogen content gradually increases with the prolongation of the enzymatic hydrolysis time, and when the enzymatic hydrolysis time is more than 3 hours, the amino nitrogen content decreases significantly. With the prolongation of enzymatic hydrolysis time, it showed a trend of first increasing and then decreasing. Therefore, under the same other conditions, when the enzymatic hydrolysis time is 3 hours, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

Comprehensive table 2, table 3, table 4 and table 5 can find out, utilize compound protease to hydrolyze the shrimp head to produce the optimal condition of shrimp seasoning sauce (being the shrimp head enzymolysis solution) be enzyme consumption 1.4%, enzymolysis pH7.4, The enzymolysis temperature is 60°C, and the enzymolysis time is 3h.

b-2) Effect of flavor protease on amino nitrogen content:

b-2-1) Effects of different enzyme dosages on amino nitrogen content: 150 g of shrimp head for each sample, enzymolysis temperature of 50°C, enzymolysis time of 4 hours, pH 7.0, adding different amounts of flavor protease for hydrolysis, The obtained content of amino nitrogen is shown in Table 6.

Table 6, the relationship between different amounts of flavor protease and amino nitrogen content

It can be seen from Table 6 that when the amount of enzyme added is less than 0.8%, the content of amino nitrogen gradually increases with the increase of enzyme amount, and when the amount of enzyme added is greater than 0.8%, the content of amino nitrogen decreases obviously. With the increase of enzyme amount, it showed a trend of first increasing and then decreasing. This may be because when the enzyme concentration reaches a certain value, all enzyme molecules have been saturated by the substrate, that is, the binding site between the enzyme molecule and the substrate has been occupied, and the speed increase slows down. Therefore, under the same other conditions, when the enzyme dosage is 0.8%, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-2-2) The effect of different enzymatic hydrolysis pH on amino nitrogen content: 150g of shrimp head for each sample, 0.8% enzyme dosage, 50°C enzymatic hydrolysis temperature, 4h enzymatic hydrolysis time, using different pH for hydrolysis, the obtained The content of amino nitrogen is shown in Table 7.

Table 7, the relationship between different enzymatic hydrolysis pH and amino nitrogen content

It can be seen from Table 7 that after the enzymatic hydrolysis pH is greater than 6.6, the enzymatic hydrolysis effect at various enzymatic hydrolysis pHs is similar, and the enzymatic hydrolysis effect at the enzymatic hydrolysis pH of 6.6 is significantly higher than that at other enzymatic hydrolysis pHs. Therefore, under the same other conditions, when the enzymatic hydrolysis pH is 6.6, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-2-3) The influence of different enzymolysis temperatures on the amino nitrogen content: 150g of each sample shrimp head, 0.8% enzyme dosage, 4h enzymolysis time, pH6.6, using different enzymolysis temperatures for hydrolysis, the obtained The content of amino nitrogen is shown in Table 8.

Table 8, the relationship between different enzymatic hydrolysis temperatures and amino nitrogen content

It can be seen from Table 8 that when the enzymatic hydrolysis temperature is lower than 50°C, the content of amino nitrogen increases gradually with the increase of temperature, while when the enzymatic hydrolysis temperature is higher than 50°C, the content of amino nitrogen decreases significantly, and the enzymatic hydrolysis temperature is 55 At ℃ and 60℃, the enzymatic hydrolysis effects of the two are similar. Therefore, under the same other conditions, when the enzymatic hydrolysis temperature is 50°C, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-2-4) Effects of different enzymolysis times on amino nitrogen content: 150 g of shrimp heads for each sample, 0.8% enzyme dosage, hydrolysis temperature of 50°C, pH 6.6, hydrolysis with different enzymolysis times, the obtained The content of amino nitrogen is shown in Table 9.

Table 9, the relationship between different enzymatic hydrolysis time and amino nitrogen content

It can be seen from Table 9 that when the enzymatic hydrolysis time is less than 4 hours, the amino nitrogen content gradually increases with the prolongation of the enzymatic hydrolysis time, and when the enzymatic hydrolysis time is longer than 4 hours, the amino nitrogen content decreases significantly. With the prolongation of enzymatic hydrolysis time, it showed a trend of first increasing and then decreasing. The reason is that as the enzymatic hydrolysis reaction proceeds, the substrate concentration decreases, and the number of peptide chains acted by the enzyme decreases; the product concentration increases, and its competitive inhibition becomes stronger; the enzyme activity decreases as the reaction proceeds. Therefore, under the same other conditions, when the enzymatic hydrolysis time is 4 hours, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

Comprehensive table 6, table 7, table 8, table 9 can find out, utilize flavor protease to hydrolyze shrimp head and produce shrimp seasoning sauce (being the best condition of shrimp head enzymolysis liquid) be enzyme consumption 0.8%, enzymolysis pH6.6, The enzymolysis temperature is 50°C, and the enzymolysis time is 4h.

b-3) Effect of proteolytic enzyme on amino nitrogen content:

b-3-1) Effects of different enzyme dosages on amino nitrogen content: 150 g of shrimp head for each sample, enzymolysis temperature of 50°C, enzymolysis time of 4 hours, pH 7.0, adding different amounts of compound protease for hydrolysis, The obtained content of amino nitrogen is shown in Table 10.

Table 10, the relationship between different amounts of proteolytic enzymes and amino nitrogen content

It can be seen from Table 10 that when the amount of enzyme added is less than 0.8%, the content of amino nitrogen increases gradually with the increase of enzyme amount, and when the amount of enzyme added is greater than 0.8%, the content of amino nitrogen decreases obviously. With the increase of enzyme amount, it showed a trend of first increasing and then decreasing. This may also be because when the enzyme concentration reaches a certain value, all enzyme molecules have been saturated by the substrate, that is, the binding site between the enzyme molecule and the substrate has been occupied, and the speed increase slows down. Therefore, under the same other conditions, when the enzyme dosage is 0.8%, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-3-2) Effect of different enzymatic hydrolysis pH on amino nitrogen content: 150g of shrimp head for each sample, 0.8% enzyme dosage, 50°C enzymatic hydrolysis temperature, 4h enzymatic hydrolysis time, using different pH for hydrolysis, the obtained The content of amino nitrogen is shown in Table 11.

Table 11, the relationship between different enzymatic hydrolysis pH and amino nitrogen content

It can be seen from Table 11 that when the enzymatic hydrolysis pH is less than 7.0, the amino nitrogen content gradually increases with the increase of the enzymatic hydrolysis pH, and when the enzymatic hydrolysis pH is greater than 7.0, the amino nitrogen content decreases significantly, that is, the amino nitrogen content increases with the enzymatic hydrolysis pH showed a trend of first increasing and then decreasing. Therefore, under the same other conditions, when the enzymatic hydrolysis pH is 7.0, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-3-3) Effects of different enzymatic hydrolysis temperatures on amino nitrogen content: 150g of shrimp head for each sample, 0.8% enzyme dosage, 4h enzymolysis time, pH7.0, using different enzymolysis temperatures for hydrolysis, the obtained The content of amino nitrogen is shown in Table 12.

Table 12, the relationship between different enzymatic hydrolysis temperatures and amino nitrogen content

It can be seen from Table 12 that before the enzymatic hydrolysis temperature reaches 60°C, the enzymatic hydrolysis effects are similar at various temperatures, and the enzymatic hydrolysis effect at 60°C is significantly higher than that at other enzymatic hydrolysis temperatures. Therefore, under the same other conditions, when the enzymatic hydrolysis temperature is 60°C, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-3-4) Effects of different enzymolysis times on amino nitrogen content: 150 g of each sample shrimp head, 0.8% enzyme dosage, 60°C enzymolysis temperature, pH 7.0, using different enzymolysis times for hydrolysis, so The obtained content of amino nitrogen is shown in Table 13.

Table 13, the relationship between different enzymatic hydrolysis time and amino nitrogen content

It can be seen from Table 13 that when the enzymatic hydrolysis time is less than 4 hours, the amino nitrogen content gradually increases with the prolongation of the enzymatic hydrolysis time, and when the enzymatic hydrolysis time is more than 4 hours, the amino nitrogen content decreases significantly, and the enzymatic hydrolysis time is 5h and 6h , the enzymatic hydrolysis effects of the two are almost the same. Therefore, under the same other conditions, when the enzymatic hydrolysis time is 4 hours, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

From Table 10, Table 11, Table 12, and Table 13, it can be seen that the optimal conditions for producing shrimp sauce by hydrolyzing shrimp heads with proteolytic enzymes are 0.8% enzyme dosage, enzymatic hydrolysis pH 7.0, enzymatic hydrolysis temperature 60°C, and enzymatic hydrolysis Time 4h.

b-4) Effect of neutral protease on amino nitrogen content:

b-4-1) Effects of different enzyme dosages on amino nitrogen content: 150g of shrimp head for each sample, enzymolysis temperature of 50°C, enzymolysis time of 4h, pH7.0, adding different amounts of neutral protease for hydrolysis , the content of amino nitrogen obtained is shown in Table 14.

Table 14, the relationship between different amounts of dispase and amino nitrogen content

It can be seen from Table 14 that the content of amino nitrogen gradually increased with the increase of the amount of enzyme added. Therefore, under the same other conditions, when the enzyme dosage is 1.4%, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-4-2) Effect of different enzymatic hydrolysis pH on amino nitrogen content: 150g of shrimp head for each sample, 1.4% enzyme dosage, 50°C enzymolysis temperature, 4h enzymolysis time, hydrolysis with different pH values, the obtained The content of amino nitrogen is shown in Table 15.

Table 15, the relationship between different enzymatic hydrolysis pH and amino nitrogen content

It can be seen from Table 15 that when the enzymatic hydrolysis pH increases from 6.8 to 7.2, the amino nitrogen content gradually increases with the increase of enzymatic hydrolysis pH, and when the enzymatic hydrolysis pH is 6.6 and 7.4, the enzymatic hydrolysis effects of the two are similar, and both are significantly lower The enzymolysis effect when the enzymolysis pH is 7.2. Therefore, under the same other conditions, when the enzymatic hydrolysis pH is 7.2, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-4-3) Effects of different enzymatic hydrolysis temperatures on amino nitrogen content: 150g of shrimp head for each sample, 1.4% enzyme dosage, 4h enzymolysis time, pH7.2, using different enzymolysis temperatures for hydrolysis, the obtained The content of amino nitrogen is shown in Table 16.

Table 16, the relationship between different enzymatic hydrolysis temperatures and amino nitrogen content

It can be seen from Table 16 that before the enzymatic hydrolysis temperature reaches 60°C, the enzymatic hydrolysis effects at various enzymatic hydrolysis temperatures are similar, and the enzymatic hydrolysis effects at 60°C are significantly higher than those at other enzymatic hydrolysis temperatures. Therefore, under the same other conditions, when the enzymatic hydrolysis temperature is 60°C, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

b-4-4) Effect of different enzymolysis time on amino nitrogen content: 150g of shrimp head for each sample, 1.4% enzyme dosage, hydrolysis temperature 60°C, pH7.2, hydrolysis with different enzymolysis time, the obtained The content of amino nitrogen is shown in Table 17.

Table 17, the relationship between different enzymatic hydrolysis time and amino nitrogen content

It can be seen from Table 17 that when the enzymatic hydrolysis time increases from 3h to 5h, the amino nitrogen content gradually decreases with the prolongation of the enzymatic hydrolysis time, and when the enzymatic hydrolysis time is 2h and 6h, the enzymatic hydrolysis effects of the two are almost the same, and both are significantly lower The enzymolysis effect when the enzymolysis time is 3h. Therefore, under the same other conditions, when the enzymatic hydrolysis time is 3 hours, the amino nitrogen content obtained from the hydrolysis of shrimp head is the most.

From Table 14, Table 15, Table 16, and Table 17, it can be seen that the best conditions for producing shrimp sauce by using neutral protease to hydrolyze shrimp heads are enzyme dosage 1.4%, enzymolysis pH 7.2, enzymolysis temperature 60°C, enzyme The solution time is 3h.

c) Determination results of amino acid composition of different protease hydrolyzates: The prepared shrimp head enzymolyzate was vacuum concentrated and vacuum freeze-dried to make powder for inspection. The test results of free amino acids in the enzymatic hydrolysis solution are shown in Table 18. The enzymatic hydrolysis solution contains a large amount of glutamic acid, aspartic acid, glycine, arginine, alanine and leucine, which are good taste components. At the end of the reaction of the enzymatic hydrolyzate, the enzymatic hydrolyzate already has a good flavor after the enzyme is deactivated, and the fragrance characteristic is obvious. Its free amino acid content is rich, and the characteristic volatile flavor of shrimp is also strong, so it can be used as a seasoning base material. If the pros and cons of hydrolysis are measured solely from the content of free amino acids, then the pros and cons of protease hydrolysis are: hydrolyzed protease > neutral protease > flavor protease > compound protease, under this condition, the total free amino acid content of hydrolyzed protease is 71.391mg/100g, so the amount of free amino acids hydrolyzed by proteolytic enzymes is the largest, that is, the degree of hydrolysis by proteolytic enzymes is optimal.

Table 18. Types of free amino acids in shrimp heads and percentage content of samples (unit: mg/100g)

In summary, the following conclusions can be drawn:

The optimal technological conditions for compound protease to hydrolyze shrimp heads alone are: enzyme dosage 1.4%, enzymatic hydrolysis pH 7.4, enzymatic hydrolysis temperature 60°C, enzymatic hydrolysis time 3 hours, and the enzymatic hydrolysis solution prepared under the optimal conditions, the amino acid content can reach 66.512 g/100g.

The optimal technological conditions for flavor protease to hydrolyze shrimp heads alone are: enzyme dosage 0.8%, enzymolysis pH 6.6, enzymolysis temperature 50℃, enzymolysis time 4h. The enzymatic hydrolyzate was prepared under optimal conditions, and the amino acid content could reach 67.438g/100g.

The optimal technological conditions for the hydrolysis of shrimp head by protease alone are: enzyme dosage 0.8%, enzymolysis pH 7.0, enzymolysis temperature 60℃, enzymolysis time 4h. The enzymatic hydrolyzate was prepared under the optimal conditions, and the amino acid content could reach 71.391g/100g.

The optimal technological conditions for neutral protease to hydrolyze shrimp head alone are: enzyme dosage 1.4%, enzymolysis pH 7.2, enzymolysis temperature 60℃, enzymolysis time 3h. The enzymatic hydrolyzate was prepared under optimal conditions, and the amino acid content could reach 70.438g/100g.

2. Preparation of shrimp flavor liquid by Maillard reaction:

1) Using the conditions in step 1 to prepare the shrimp head enzymatic hydrolysis solution, the specific steps are as follows: take out the frozen preserved shrimp head and thaw it, first mash it with a mortar, and then add distilled water at a mass ratio of 1:1. Stir the mixture evenly and place it in a beater for beating until the mixture is completely crushed to obtain crushed shrimp head liquid. Adjust the pH of the crushed shrimp head liquid to 7, add 0.8% hydrolytic protease to the crushed shrimp head liquid, mix evenly and place in a water bath at 60°C for 4 hours, inactivate the enzyme after 4 hours, centrifuge to take the supernatant, filter, That is, the required shrimp head enzymatic hydrolysis solution is obtained.

2) Preparation of shrimp flavor liquid: add shrimp head enzymatic solution, reducing sugar and amino acid into the reaction test tube as reaction precursors, adjust the appropriate pH value, and put it in a pressure cooker or a constant temperature water bath at a certain temperature to react for a period of time , to obtain the shrimp flavor liquid.

2-1) Selection of reducing sugar: According to the principle and characteristics of the Maillard reaction, temperature 100° C., pH=7, time 40 min were used as reaction conditions, and 4% reducing sugar was added for thermal reaction. Analyze the obtained thermal reaction products to find out the optimum reducing sugar.

Determination of the proportion of compound reducing sugars: keep the basic conditions unchanged, the total amount of reducing sugars remains unchanged, and control the proportion of the two sugars with the strongest flavor for thermal reaction. The intensity of the shrimp flavor of the thermal reaction products was sorted and tested, and then the Friedman test and the Page test were used to judge whether there were significant differences between the tested samples. Determine the ratio of the two reducing sugars that produces the strongest shrimp flavor.

2-2) Determination of amino acids: temperature 100° C., pH=7, time 40 min, optimal reducing sugar 4% as the reaction conditions, respectively add 3% of each amino acid for thermal reaction. The obtained thermal reaction product is analyzed, and the most suitable amino acid is analyzed.

Determination of compound amino acids: keep the basic conditions unchanged, the total amino acid content unchanged, and control the ratio of the two amino acids with the strongest flavor for thermal reaction. The intensity of the shrimp flavor of the thermal reaction products was sorted and tested, and then the Friedman test and the Page test were used to judge whether there were significant differences between the tested samples. Determine the ratio of the two amino acids that produce the strongest shrimp flavor.

2-3) Single factor experiment of adding amount of reducing sugar: temperature 100°C, pH=7, time 40min, amino acid added amount 3% as reaction conditions, reducing sugar added amount was 2%, 3%, 4%, 5% respectively , 6% for Maillard reaction.

2-4) Single factor experiment of amino acid addition amount: temperature 100°C, pH=7, time 40min, reducing sugar addition amount 4% were used as reaction conditions, amino acid addition amount were 1%, 2%, 3%, 4%, 5% undergo the Maillard reaction.

2-5) Reaction pH single factor experiment: the reaction conditions were 4% reducing sugar, 3% amino acid, time 40min, temperature 100°C, pH 4, 5, 6, 7, 8 Maillard respectively.

2-6) Reaction time single factor experiment: temperature 100°C, pH=8, reducing sugar 4%, amino acid 3% were the reaction conditions, and the reaction times were 20, 30, 40, 50, 60 min respectively.

2-7) Reaction temperature single-factor experiment: the temperature is 80°C, 90°C, 100°C, 110°C, and 120°C for 50 minutes at pH=8, reducing sugar 4%, and amino acid 3%, respectively. German reaction.

2-8) Orthogonal experiment design: In order to obtain the best thermal reaction conditions, three factors and three levels of time, temperature, and pH are used for the three-level orthogonal experiment, and the product is subjected to sensory analysis by scoring test method.

3) Result analysis of shrimp flavor liquid: result analysis is sensory analysis, and sensory analysis is a simple analysis method (the evaluator makes a qualitative description of a certain index or each index of the sample characteristics, and describes the quality of the sample as completely as possible), sorting Inspection method (the method of comparing several samples and sorting them according to the size of a certain quality is called sorting inspection method), scoring inspection method (the scoring method refers to the evaluation of the characteristics and characteristics of the samples according to the preset evaluation criteria, The degree of preference is evaluated with a numerical scale, and then replaced with a scoring method).

The corresponding scoring criteria are shown in Table 19 below:

Table 19. Sensory scoring criteria

3) Determination of the precursor substances of the Maillard reaction: the precursor substances of the Maillard reaction are amino acids and reducing sugars. Although the enzymatic hydrolysis solution of shrimp head is rich in amino acids, it cannot produce full shrimp flavor, so it is necessary to add some Some amino acids and glucose to make the flavor more suitable for the general public.

3-1) Determination of reducing sugars: different reducing sugars react with shrimp head enzymatic hydrolyzate and produce different flavors. The browning rate of pentose sugars is 10 times that of hexoses, and the rate of hexoses is faster than that of disaccharides. The order of browning speed of pentoses in reducing monosaccharides is: ribose > arabinose > xylose, the order of hexoses is: galactose > mannose > glucose, and common disaccharides include maltose, lactose, sucrose, etc. Comprehensive reducing sugar type and reaction speed, choose glucose, xylose, sucrose, ribose. Using the thermal product without added reducing sugar as a reference standard, sensory analysis was carried out on the thermal product with reducing sugar added.

Table 20. Sensory evaluation of different reducing sugar reactions

As can be seen from Table 20, sucrose is not suitable for addition in the reaction. The effect of ribose is similar to that of glucose or xylose, but ribose is more expensive, so xylose and glucose are selected as additives.

Determination of the proportion of reducing sugar: the reaction speed of xylose is faster than that of glucose, and the flavor of shrimp is different, and the flavor produced by different ratios between them will also be different. Therefore, in this experiment, glucose and xylose were set to react in six different ratios of 5:0, 4:1, 3:2, 2:3, 1:4, and 0:5, respectively labeled A, B, C, D, E, F, the response results are evaluated by scoring method. The rank and rank sum of the scoring results are shown in Table 21:

Table 21. Ranks and rank sums of products with different ratios of glucose and xylose

Use the Kramer test method to analyze the data. The critical value of the test table is divided into the upper and lower sections by the sequence check method, and the rank sum of each sample is compared with the maximum value R _imax and the minimum value R _imin of the upper section. If the rank sum of the samples is not less than R _imax or not greater than R _imin , it means that there are significant differences among the samples. Then check the degree of difference between samples through the next paragraph. If the R _n of the samples falls within the range of the lower paragraph, they can be classified as a group, indicating that there is no difference between them; if the R _n of the samples falls outside the range of the lower paragraph, they fall within Samples falling outside the upper limit and those falling outside the lower limit are grouped separately.

Look up the sequence test method test table, α=5% and α=1%, corresponding to the critical value of J=6 and P=6:

5% significant level 1% significant level

Upper section 11～31 9～33

Lower section 14～28 12～30

It can be seen from the upper part of the 1% significant level that the maximum R _imax =33= _RB , so there are significant differences among the six samples at the 1% significant level. It can be known from the following paragraph that R _B =33>R _imax =30, R _C =30=R _imax , R _A =10<R _imin =12, R _C , R _D , _RE , and R _F are all in the range of 12 to 30 , so samples can be divided into three groups: B CDEF A

Conclusion: At the 1% significant level, sample B is the best, followed by samples C, D, E, and F, and sample A is the worst. Therefore, the ratio of reducing sugar selected is 1:4 for xylose to glucose.

3-2) Determination of amino acids: Different amino acids react with reducing sugars to produce different characteristic flavors. There is no relevant report on which amino acids participate in the reaction to produce shrimp aroma. Amino acids participate in the reaction, namely cystine, cysteine, arginine, glycine, alanine, proline, aspartic acid, glutamic acid. The corresponding sensory evaluation is shown in Table 22:

Table 22. Sensory evaluation of different amino acid reactions

It can be seen from Table 22 that the addition of cystine, glycine, alanine and arginine helps to enhance the taste of shrimp, so we choose the above four amino acids to compound in pairs and react with reducing sugars for thermal reaction.

Determination of compound amino acids: According to Table 22, we selected four amino acids such as cystine, glycine, alanine, and arginine to react with reducing sugar in pairs. The mass ratio of various amino acids was 1:1. As a result, the ranking test method was used for sensory evaluation, and the Kramer test method was used for analysis. The amino acid interaction table is shown in Table 23:

Table 23. Amino acid interaction table

Table 24. Rank and rank sum of samples

Look up sequence test method test table α=5% and α=1%, corresponding to the critical value of J=6 and P=6:

5% significant level 1% significant level

Upper section 11～31 9～33

Lower section 14～28 12～30

It can be known from the above that the maximum R _imax =33= _RD and the minimum R _imin =9>8.5, so there are significant differences among the six samples at the 1% significant level. It can be known from the following paragraph that R _D =33>R _imax =30, Rc=8.9<12, and R _A , R _B , _RE , and R _F are all in the range of 12 to 30, so the samples can be divided into three groups: D ABEF C

Conclusion: At the 1% significant level, sample D is the best, followed by samples A, B, E, and F, and sample C is the worst. Therefore, the selected compound amino acids are glycine and arginine. Since the 1:1 compound ratio of glycine and arginine produces a satisfactory shrimp flavor, the compound ratio is selected to be 1:1.

3-3) Determination of the basic parameters of the reaction: the determination of the five factors of reducing sugar, amino acid, reaction time, reaction temperature and reaction pH.

3-3-1) Single factor experiment of adding amount of reducing sugar: temperature 100°C, pH=7, time 40min, amino acid 3% as reaction conditions, adding amount of reducing sugar were 2%, 3%, 4%, 5% respectively , 6% for the reaction, and respectively labeled A, B, C, D, E. Use the sensory scoring method to score, and the corresponding results are shown in Table 24. Then use the Friedman test to determine whether there is a significant difference between the tested samples, and use multiple comparisons and grouping to determine the optimal amount of reducing sugar added.

Table 24. Rank and rank sum of sensory evaluation

The Friedman test was used to analyze whether there were significant differences among the five samples corresponding to A, B, C, D, and E. First use the following formula to find the statistic F.

In Formula I, J represents the number of judges; P represents the number of samples; R ₁ , R ₂ ,..., R _P represents the rank sum of each sample.

Check the Friedman rank sum approximate critical value table, if the calculated F is greater than or equal to the critical value corresponding to P, J, α, it can be determined that there is a significant difference between the samples; if it is less than the corresponding critical value, it can be determined that there is a significant difference between the samples No significant difference.

F=18.8 was calculated according to the above formula, and X(6, 5, 0.05)=9.49 was obtained by checking the critical value table, so it can be judged that there is a significant difference between the samples at the 5% significant level.

After judging that there are significant differences between samples, multiple comparisons and grouping are used to identify significant differences among samples. According to the rank and RP of each sample, the samples are initially sorted from small to large, and the ranking is as follows:

The formula for calculating the critical value r(I, α) is as follows:

According to the formula, r(I, α)=3.87q(I, α), the value of q(I, α) can be looked up in the table. According to the calculation, r(5,0.05)=14.94; r(4,0.05)=14.04; r(3,0.05)=12.81; r(2,0.05)=10.72;

R _C -R _E ＝29-7.5＝21.5>r(5,0.05)

R _C -R _D =29-12.5=16.5>r(4,0.05)

R _C -R _B =29-18.5=10.5<r(3,0.05)

The order of the above rank sum subtraction _is , R _{C -RA} , R _A -RE , R _A -R _D , R _A -R _B , R _B -R _E , R _B -R _D , R _D -R _E ; Compare the rank sum difference between the samples with the size of r, if the rank sum difference is greater than or equal to the corresponding r, it means that there is a significant difference between the two samples; if the rank sum difference is less than the corresponding r, it means this Samples with no significant difference between the two samples are underlined.

Based on the above analysis results and the degree of difference, it can be concluded that C AB DE

It can be seen that the flavor of 4% reducing addition is the best, followed by 2%, 3% addition, and 5%, 6% addition is the worst. Therefore, considering comprehensive consideration, the addition of reducing sugar was selected at a level of 4%.

3-3-2) Single factor experiment of amino acid addition amount: temperature 100°C, pH=7, time 40min, reducing sugar 4% were used as the reaction conditions, the amino acid addition amount was 1%, 2%, 3%, 4%, 5% reacted and labeled A, B, C, D, E respectively. Use the sensory scoring method to score, and then use the Friedman test to determine whether there is a significant difference between the tested samples, and use multiple comparisons and grouping to determine the optimal amino acid addition amount. See Table 25 for the ranks and rank sums of the five sensory samples.

Table 25. Rank and rank sum of sensory evaluation

According to the analysis in Table 25, it can be obtained that F=16.26>X(6, 5, 0.05)=9.49, so it can be judged that there is a significant difference between the samples at the 5% significant level. After further analysis of multiple comparisons and grouping: CD ABE

It can be seen from the degree of difference that 3% and 4% amino acid additions have the best flavor, followed by 1%, 2%, and 5% additions. Considering the economic cost and the preservation of the original shrimp flavor, the amino acid addition level is chosen to be 3%.

3-3-3) Reaction pH single factor test: Reducing sugar 4%, amino acid 3%, time is 40min, temperature is 100 ℃, pH is respectively 4, 5, 6, 7, 8 to carry out the reaction, and label A, respectively B, C, D, E. Use the sensory scoring method to score, and then use the Friedman test to determine whether there is a significant difference between the tested samples, and use multiple comparisons and grouping to determine the optimal reaction pH. The ranks and rank sums of the five sensory samples are shown in Table 26 below.

Table 26. Rank and rank sum of sensory evaluation

According to the analysis in Table 26, F=14.2>X(6, 5, 0.05)=9.49, so it can be judged that there is a significant difference between the samples at the 5% significant level. Further analysis after multiple comparisons and grouping: CDE AB

It can be seen that the reaction pH of C, D and E has the best flavor, and the reaction pH of A and B is second. Therefore, the level of reaction pH 8 was selected comprehensively.

3-3-4) Reaction time single factor test: temperature 100°C, pH=8, reducing sugar 4%, amino acid 3% were the reaction conditions, and the reaction times were 20, 30, 40, 50, 60 min, respectively. The samples were labeled A, B, C, D, and E respectively, and scored by the sensory scoring method, and then the Friedman test was used to determine whether there was a significant difference between the tested samples, and multiple comparisons and grouping were used to determine the best reaction time. The ranks and rank sums of the five sensory samples are shown in Table 27 below.

Table 27. Rank and rank sum of sensory evaluation

According to the analysis in Table 27, F=16.4>X(6, 5, 0.05)=9.49, so it can be judged that there is a significant difference between the samples at the 5% significant level. Further analysis after multiple comparisons and grouping: DE ABD

It can be seen that the reaction time of D and E is the best, and the reaction time of A, B and D is second. Therefore, considering comprehensive consideration, choose the level of reaction time as 50min.

3-3-5) Reaction temperature single factor test: the reaction is carried out under the conditions of pH = 8, reducing sugar 4%, amino acid 3%, time is 50min, and temperature is 80, 90, 100, 110, 120 respectively, and respectively labeled A, B, C, D, E. Use the sensory scoring method to score, and then use the Friedman test to determine whether there is a significant difference between the tested samples, and use multiple comparisons and grouping to determine the optimal reaction temperature. The ranks and rank sums of the five sensory samples are shown in Table 28 below.

Table 28. Rank and rank sum of sensory evaluation

According to the analysis in Table 28, it can be obtained that F=17.2>X(6, 5, 0.05)=9.49, so it can be judged that there is a significant difference between the samples at the 5% significant level. After further analysis with multiple comparisons and grouping: CB DEA

It can be seen that the reaction temperature of C and B has the best flavor, and the reaction temperature of A, D, and E is second. Therefore, the level of reaction temperature of 100°C should be selected comprehensively.

3-3-6) Optimization of the basic parameters of the reaction: According to the above single factor test, select three optimal levels from the three factors of reducing sugar, amino acid addition amount and reaction time, and carry out orthogonal analysis according to L ₉ (3 ³ ) Test, test factors and results are shown in Table 29, Table 30 and Table 31:

Table 29. Orthogonal test factor level table

Table 30. Orthogonal experiment arrangement and results

T _i represents the sum of the same level of each factor, and K _i represents the average value of the sum of the same level of each factor.

Table 31. Orthogonal test analysis of variance table

The results of the F test showed that the three factors had no significant influence on the response effect. The reason may be that the experimental error in this example is large and the degree of freedom of error is small (only 2), which makes the sensitivity of the test low, thus covering up the significance of the factors under investigation.

Since each factor has no significant effect on weight gain, it is not necessary to carry out multiple comparisons among the levels of each factor. At this time, the level A ₂ , B ₁ , and C ₂ with the largest average number can be selected from the table to form the optimal level combination A ₂ B ₁ C ₂ , that is, reducing sugar addition 4%, amino acid addition 2%, and reaction time 50min is the best combination.

In summary, it can be known that the best reducing sugars to be added to precursor substances are glucose and xylose, with a mass ratio of 4:1; the best added amino acids are glycine and arginine, with a mass ratio of 1:1. The best reaction conditions obtained by single factor test are: reducing sugar 4%, amino acid 3%, pH=8, reaction time 50min, temperature 100℃. Three-factor and three-level optimization experiments show that the optimal reducing sugar is 4%, amino acid 2%, and time 50min. Therefore, at the end of the experiment, it was concluded that the best preparation conditions for shrimp flavor liquid are: reducing sugar (glucose: xylose = 4:1) 4%, amino acid (glycine: arginine = 1:1) 2%, pH = 8, temperature 100°C, time 50min.

Claims (6)

1. A preparation method of shrimp flavor liquid, comprising the steps of: 1) Preparation of shrimp head enzymatic hydrolysis liquid: mixing and pulverizing shrimp heads and water to obtain shrimp head crushing liquid; then mixing the shrimp head crushing liquid and protease for enzymolysis to obtain shrimp head enzymatic hydrolysis liquid; Before the crushed shrimp head liquid is mixed with protease, the pH value of the crushed shrimp head liquid is adjusted; When the protease is a composite protease, the added amount of the composite protease is 1.0%-1.5% of the mass of the crushed shrimp head liquid; The conditions of the enzymolysis are as follows: the enzymolysis temperature is 50-60° C., the enzymolysis time is 3 hours, and the enzymolysis pH is 7.0-7.5; When the protease is a flavor protease, the added amount of the flavor protease is 0.5%-1.0% of the mass of the crushed shrimp head liquid; The conditions of the enzymolysis are as follows: the enzymolysis temperature is 45-55° C., the enzymolysis time is 4 hours, and the enzymolysis pH is 6.5-7.0; In step 1), the shrimp head is the shrimp head of Penaeus vannamei; In step 1), the step of further purifying the enzymatic hydrolyzate of shrimp head is also included: inactivating the enzymatic hydrolyzate of shrimp head at 95-105°C for 5-15min; The clear liquid is filtered to obtain the purified shrimp head enzymatic solution; 2) Prepare shrimp flavor liquid: mix reducing sugar, amino acid and shrimp head enzymolysis liquid described in step 1) to carry out Maillard reaction to obtain shrimp flavor liquid; The mass ratio of the reducing sugar, the amino acid and the shrimp head enzymolysis solution in step 1) is (2-6):(1-5):100; The reducing sugar is a mixed sugar of xylose and glucose with a mass ratio of 1:(2-5); The amino acid is a mixed amino acid of glycine and arginine with a mass ratio of 1:(0.5-3). 2. the preparation method as claimed in claim 1 is characterized in that: in step 1), the mass ratio of described shrimp head and water is 1: (1-2); The pulverized particle size is 120-180 μm. 3. the preparation method as claimed in claim 1 or 2 is characterized in that: in step 2), the mass ratio of described reducing sugar, described amino acid and step 1) in described shrimp head enzymolysis solution is (2- 4): (2-4): 100. 4. the preparation method as claimed in claim 1 or 2 is characterized in that: in step 2), the condition of described Maillard reaction is as follows: reaction temperature is 80-120 ℃, reaction time is 20-60min, reaction system The pH is 4-8. 5. The shrimp flavor liquid or shrimp head enzymatic hydrolyzate obtained by the preparation method described in any one of claims 1-4. 6. the application of the shrimp flavor liquid and/or shrimp head enzymatic hydrolysis liquid described in claim 5 in the preparation of food flavor additives.