Method for improving stability of modified starch in oyster sauce

Abstract

The invention relates to the technical field of food, and particularly discloses a method for improving the stability of modified starch in oyster sauce. Through pH, reaction temperature and shear emulsification coupling regulation and control, the coupling effect of the modified starch-protein compound is improved, and the heat-resistant stability and shear-resistant stability of the modified starch are improved, so that the modified starch is not easy to damage in the processing process, and starch particles are more complete; through the modified starch-protein coupling effect, the heat resistance and shear resistance of the modified starch are improved, the influences of storage temperature, packing materials and the like in the storage process of the oyster sauce can be effectively resisted, the crushing and disintegration rate of the modified starch is reduced, the thinning and bleeding rate of the oyster sauce is delayed, and the shelf life and posture of the oyster sauce are improved.

Description

Technical Field

[0001] The present application relates to the field of food technology, and in particular to a method for improving the stability of modified starch in oyster sauce. Background Art

[0002] Oyster sauce is a condiment with a uniform and delicate body and moderate viscosity. Its unique flavor is deeply loved by consumers. At present, the oyster sauce sold on the market often has the phenomenon of oyster sauce thinning and stratification, which affects the sensory quality of oyster sauce. The occurrence of this phenomenon is caused by many factors, which may be related to the raw materials, processing technology, storage environment and packaging materials selected by the manufacturer. Research and investigation found that the raw materials, packaging materials and storage environment of oyster sauce selected by most oyster sauce manufacturers are not very different. The phenomenon of oyster sauce water separation and thinning may be related to the production process. The traditional processing method of oyster sauce is to heat and dissolve oyster juice, white sugar, edible salt, etc. in a cooking pot, heat to 70-80℃, mix the modified starch with water evenly, put it into the cooking pot, heat all the materials to 100℃, keep warm for 20-30min, cool to 60-70℃ after the insulation, and fill it. This traditional oyster sauce processing method has a slow heat transfer rate between the oyster sauce materials after the materials become thick, and the heating to the set temperature and insulation time are long. The modified starch is easily overheated, and after being sheared and transported by the equipment, a small amount of starch particles are damaged, affecting the physical stability of the oyster sauce during its shelf life.

[0003] Patent publication number CN 110839859 A discloses a method for preparing oyster sauce, which comprises heating white sugar, salt, soy sauce, oyster water, etc. to 70-80°C, adding modified starch, heating to 100°C, adding xanthan gum and continuing to heat until boiling, continuing to heat caramel, monosodium glutamate, etc., and keeping boiling for 20 minutes to obtain oyster sauce. This processing method still has the problem of long cooking time, and the overheating of oyster sauce reduces the shear resistance of starch, resulting in a small amount of damage to starch particles, affecting the physical stability of oyster sauce during the shelf life. Patent publication number CN 113303464A discloses a method for rapid gelatinization of modified starch. Through the method of "low temperature treatment-shear treatment-high temperature treatment", the gelatinization time of modified starch is shortened, and the utilization rate of modified starch in oyster sauce is improved, but shearing also leads to the risk of a small amount of starch damage, affecting the physical stability of oyster sauce during the shelf life.

[0004] In the special discussion of "Progress in the Study of the Interaction of Protein-Polyphenol-Starch Ternary System and Its Effect on the Function of Each Component", Tian Ziang et al. mentioned that protein can react with starch to form a protein-starch binary complex, which can protect the integrity of starch granules, make them less susceptible to shear damage, and improve the stability of starch. Liu Changnian et al. also mentioned in the article "Progress in the Study of Protein / Lipid-Starch Interaction and Its Effect on Slowing Starch Digestion Rate" that protein and hydrolysate (peptides and amino acids) can form protein-starch complexes with starch, which can make the starch structure more compact, enhance shear resistance, improve the integrity of starch granules, and make it less susceptible to swelling, thereby hindering starch hydrolysis. However, the above literature mentioned that starch and protein can be obtained by heat treatment such as extrusion, gelatinization, and cooking, enzyme treatment, heat treatment-enzyme hydrolysis, etc. The high-temperature heat treatment method will lead to starch gelatinization. Starch gelatinization requires a lot of water, which is not conducive to the dissolution of other materials and starch is difficult to be evenly dispersed in other materials after gelatinization. The enzyme treatment method may affect the change of protein content and have a certain effect on the characteristic aroma of the product.

[0005] In the process of oyster sauce processing, long-term heating and equipment shearing can easily cause starch damage and swelling, affecting the stability of the oyster sauce. In addition, the existing traditional oyster sauce production process is to mix and cook all materials, and protein is easy to compound with other materials containing hydroxyl / amino groups, which weakens the cross-linking effect of modified starch-protein. Therefore, a method for improving the stability of modified starch in oyster sauce is urgently needed. Summary of the invention

[0006] The purpose of the present application is to overcome the deficiencies of the above-mentioned prior art and provide a method for improving the stability of modified starch in oyster sauce. The present application aims to couple modified starch and protein under conditions where the starch temperature is lower than the gelatinization temperature without increasing the difficulty of process operation and without affecting the characteristic flavor of the product, so as to achieve the purpose of improving the integrity of starch granules, delaying the disintegration rate of starch, and improving the physical stability of oyster sauce during the shelf life.

[0007] To achieve the above purpose, the technical solution adopted by this application is:

[0008] The present application provides a method for improving the stability of modified starch in oyster sauce, comprising the following steps:

[0009] S1, mixing modified starch, oyster juice and water to obtain a mixture, adjusting the pH value of the mixture to 3-5, and obtaining a treated mixture I;

[0010] S2, shearing and emulsifying the treated mixture I to obtain a modified starch-protein complex;

[0011] S3, mixing the seasoning and water to form a mixed solution, then adding the modified starch-protein complex to the mixed solution to obtain a mixture II, adjusting the pH value of the mixture II to 5.5-6, heating and keeping warm, and finally cooling and filling to obtain an oyster sauce product.

[0012] In the technical solution of the present application, the modified starch contains abundant hydroxyl groups, and the proteins (peptides and amino acids) in the oyster sauce contain abundant carboxyl and amino groups. The present application adjusts the pH value to acidic, so that some hydroxyl groups in the starch ionize protons, which are easy to couple with the proteins in the oyster sauce, and further adopts shear emulsification to make the proteins in the oyster sauce adhere to the modified starch to form a modified starch-protein complex. The attachment of proteins around the modified starch can hinder the interaction between the modified starch and water, enhance the shear resistance of the modified starch, protect the integrity of the modified starch particles, thereby delaying the disintegration rate of the modified starch and improving the physical stability of the oyster sauce during the shelf life.

[0013] The method of the present application improves the processing resistance of modified starch by constructing a starch-protein complex, making the modified starch less likely to swell and break, thereby improving the thickening stability of the modified starch, delaying starch disintegration, reducing the amount of water precipitation and the dilution rate of oyster sauce, and improving the overall stability of the oyster sauce. This solves the problem that during the processing of oyster sauce, long-term heating and equipment shearing may easily lead to starch breakage and swelling, thereby affecting the stability of the oyster sauce.

[0014] In addition, the existing traditional oyster sauce production process is to mix and cook all the materials. Protein is easy to compound with other materials containing hydroxyl / amino groups, which weakens the cross-linking effect of modified starch-protein. The method of the present application is used to preferentially construct a modified starch-protein complex, which is then mixed with other materials and heated, so that the starch structure in the oyster sauce is compacted and the processing resistance is enhanced. Compared with the traditional process, the method of the present application can slow down the disintegration rate of modified starch.

[0015] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in step S1, the mass ratio of modified starch, oyster sauce and water is 1:(3-4):2, preferably, the mass ratio of modified starch, oyster sauce and water is 1:3:2.

[0016] In some specific embodiments, the weight proportion of modified starch is 5 parts, the weight proportion of oyster juice is 15 parts, and the weight proportion of water is 10 parts.

[0017] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in the step S1, the temperature of the mixture is preheated to 45-55° C., and the insulation time is 10-20 minutes.

[0018] The present application preheats the mixture to improve the coupling effect of the modified starch-protein complex, improve the heat stability and shear stability of the modified starch, make the modified starch less likely to be damaged during processing, and make the starch granules more complete.

[0019] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in step S1, the pH value of the mixture is adjusted to 4.

[0020] In the present application, the pH value of the mixture is adjusted to 3-5, preferably to 4. Some hydroxyl groups in the modified starch ionize protons, which are easily coupled with proteins in oyster sauce, so that the proteins are attached to the modified starch to form a modified starch-protein complex. The attachment of proteins around the modified starch can hinder the interaction between the modified starch and water, enhance the shear resistance of the modified starch, protect the integrity of the modified starch particles, thereby delaying the disintegration rate of the modified starch and better improving the physical stability of the oyster sauce during the shelf life.

[0021] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in step S1, an acid solution is used to adjust the pH value of the mixture to 3 to 5;

[0022] The acid includes citric acid.

[0023] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in step S2, the rotation speed of shear emulsification is 2000-4000 rpm, and the time of shear emulsification is 10-20 min.

[0024] The present application adopts the above-mentioned shear emulsification effect to further promote the coupling of modified starch and protein under acidic conditions to form a modified starch-protein complex.

[0025] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in step S2, the rotation speed of shear emulsification is 2000 rpm, and the time of shear emulsification is 10 min.

[0026] By adopting the above-mentioned shear emulsification conditions, the coupling effect of the modified starch-protein complex can be better improved, the heat stability and shear stability of the modified starch can be improved, the breakage of the deformed starch during processing can be reduced, and the integrity of the modified starch particles can be improved.

[0027] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, the seasoning includes white sugar, edible salt, monosodium glutamate, caramel color, xanthan gum and potassium sorbate;

[0028] The mass ratio of white sugar, table salt, MSG, caramel color, xanthan gum and potassium sorbate is 10:5:5:0.5:0.2:0.1.

[0029] In some specific embodiments, the weight portion of white granulated sugar is 10 parts, the weight portion of edible salt is 5 parts, the weight portion of monosodium glutamate is 5 parts, the weight portion of caramel color is 0.5 parts, the weight portion of xanthan gum is 0.2 parts, and the weight portion of potassium sorbate is 0.1 parts.

[0030] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in step S3, the mass ratio of seasoning, water and modified starch-protein complex is 20.8:(44.2-49.2):(30-35), preferably, the mass ratio of seasoning, water and modified starch-protein complex is 20.8:49.2:30.

[0031] In some specific embodiments, the weight proportion of the seasoning is 20.8 parts, the weight proportion of water is 49.2 parts, and the weight proportion of the modified starch-protein complex is 30 parts.

[0032] The present application gives priority to constructing a modified starch-protein complex, and then mixing and heating it with other materials to make the starch structure in the oyster sauce compact and enhance the processing resistance. Compared with the traditional process, the method of the present application can slow down the disintegration rate of the modified starch.

[0033] As a preferred embodiment of the method for improving the stability of modified starch in oyster sauce described in the present application, in step S3, the heating and heat preservation conditions are: the temperature is 100° C., and the heat preservation time is 15 to 25 minutes;

[0034] The cooling temperature is 60-70°C.

[0035] In the technical solution of the present application, the temperature of the mixture is preheated to 50°C, the pH value of the mixture is adjusted to 4, and shear emulsification is applied at 2000rpm for 10 minutes to cross-link the modified starch and protein, thereby improving the processing resistance of the oyster sauce. After shearing, the decrease rate of the volume-weighted particle size D10 of the oyster sauce is delayed by 4.21 μm, and the modified starch particles after shearing are more complete and relatively compact.

[0036] The method of the present application slows down the rate of dilution and water precipitation of oyster sauce. In the accelerated shelf life test at 50°C and 30 days, the water precipitation of oyster sauce is reduced by 16.82g, and the viscosity decrease rate of oyster sauce is slowed by 32.57%; after 60 days of accelerated shelf life, the water precipitation of oyster sauce is reduced by 24.95g, and the viscosity decrease rate of oyster sauce is slowed by 55.40%.

[0037] Compared with the prior art, this application has the following beneficial effects:

[0038] The present application provides a method for improving the stability of modified starch in oyster sauce. The present application improves the coupling effect of modified starch-protein complex by regulating pH, reaction temperature and shear emulsification coupling, improves the heat stability and shear stability of modified starch, makes the modified starch less likely to be damaged during processing, and makes the starch granules more complete; through the modified starch-protein coupling effect, the heat resistance and shear resistance of the modified starch are improved, and the oyster sauce can be effectively protected against the influence of storage temperature, packaging materials, etc. during storage, the crushing and disintegration rate of the modified starch is reduced, the dilution and water separation rate of the oyster sauce are delayed, and the shelf life of the oyster sauce is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Microscopic examination of starch particles of the oyster sauce starting sample prepared in Example 1;

[0040] Figure 2 The microscopic examination of the sheared oyster sauce starch particles in Example 1;

[0041] Figure 3 Microscopic examination of starch particles of the oyster sauce starting sample prepared in Comparative Example 1;

[0042] Figure 4 This is the microscopic examination of the sheared oyster sauce starch particles of Comparative Example 1;

[0043] Figure 5 The initial sample of the oyster sauce shelf life of Example 1 was examined under a microscope;

[0044] Figure 6 Microscopic examination of starch granules of the oyster sauce of Example 1 after accelerating the shelf life for 60 days;

[0045] Figure 7 The sample of the oyster sauce at the beginning of the shelf life of Comparative Example 1 was examined under a microscope;

[0046] Figure 8 Microscopic examination of starch granules of the oyster sauce of Comparative Example 1 after accelerated shelf life of 60 days. DETAILED DESCRIPTION

[0047] In order to better illustrate the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0048] In the following examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified, and the components and raw materials used in each parallel experiment are of the same type.

[0049] Example 1: A method for improving the stability of modified starch in oyster sauce

[0050] The present embodiment provides a method for improving the stability of modified starch in oyster sauce, comprising the following steps: (1) modified starch-oyster sauce warm treatment: 5 parts of modified starch, 15 parts of oyster sauce, and 10 parts of water are stirred evenly to obtain a mixture, the mixture is preheated to 50° C., citric acid is added to adjust the pH value of the mixture to 4, and the mixture is kept warm for 10 minutes to obtain a treated mixture I.

[0051] (2) Modified starch-protein shear coupling: The treated mixture I was subjected to shear emulsification for 10 min using a shear emulsifier at a speed of 2000 rpm to further promote the modified starch-oyster juice coupling and form a modified starch-protein complex.

[0052] (3) Cooking oyster sauce: add 10 parts of white sugar, 5 parts of edible salt, 5 parts of monosodium glutamate, 0.5 parts of caramel color, 0.2 parts of xanthan gum, 0.1 parts of potassium sorbate and 49.2 parts of water into a cooking pot, dissolve and mix evenly, heat to 75°C, add 30 parts by weight of the obtained modified starch-protein complex into the cooking pot to obtain mixture II, add citric acid to adjust the pH value of mixture II to 5.5, heat to 100°C, keep warm for 20 minutes, and cool to 65°C.

[0053] (4) Oyster sauce filling: Use a rotor pump with a maximum speed of 2520 rpm, adjust the frequency of the rotor pump to 50 Hz, pump the cooked material to the filling machine for filling, and then obtain the oyster sauce product.

[0054] Example 2: A method for improving the stability of modified starch in oyster sauce

[0055] Compared with Example 1, the difference of Example 2 is that in step (1), the mixture is not preheated to 50° C. for warm treatment, and the other preparation conditions are the same as those of Example 1.

[0056] Example 3: A method for improving the stability of modified starch in oyster sauce

[0057] Compared with Example 1, the difference of Example 3 is that in step (1), citric acid is added to adjust the pH value of the mixture to 3, and the other preparation conditions are the same as those of Example 1.

[0058] Example 4: A method for improving the stability of modified starch in oyster sauce

[0059] Compared with Example 1, the difference of Example 4 is that in step (1), citric acid is added to adjust the pH value of the mixture to 5, and the other preparation conditions are the same as those of Example 1.

[0060] Example 5: A method for improving the stability of modified starch in oyster sauce

[0061] Compared with Example 1, the difference of Example 5 is that in step (2), a shear emulsifier is used, the speed is set to 4000 rpm, the shear emulsification is performed for 10 minutes, and the coupling treatment is performed; other preparation conditions are the same as those of Example 1.

[0062] Example 6: A method for improving the stability of modified starch in oyster sauce

[0063] Compared with Example 1, the difference of Example 6 is that in step (2), a shear emulsifier is used, the speed is set to 2000 rpm, the shear emulsification is performed for 20 minutes, and the coupling treatment is performed; the other preparation conditions are the same as those of Example 1.

[0064] Comparative Example 1

[0065] Comparative Example 1 provides a method for preparing an oyster sauce product, comprising the following steps:

[0066] (1) Modified starch treatment: 5 parts of modified starch are added to 15 parts of water to obtain modified starch slurry;

[0067] (2) Cooking oyster sauce: Dissolve 10 parts of oyster juice, 10 parts of white sugar, 5 parts of edible salt, 5 parts of monosodium glutamate, 0.5 parts of caramel color, 0.2 parts of xanthan gum, 0.1 parts of potassium sorbate and 49.2 parts of water in a certain proportion and mix them evenly, heat to 75° C. and cook, add 20 parts of modified starch slurry, add citric acid to adjust the pH value to 5.5, continue to heat to 100° C., keep warm for 20 minutes, and cool to 60-70° C.;

[0068] (3) Oyster sauce filling: Use a rotor pump with a maximum speed of 2520 rpm / min, adjust the frequency of the rotor pump to 50 Hz, pump the cooked material to the filling machine for filling, and then obtain the oyster sauce product.

[0069] Comparative Example 2

[0070] Compared with Example 1, the difference of Comparative Example 2 is that in step (2), no shear emulsification treatment is performed, a stirring paddle is used, the speed is set to 50 rpm, and stirring is performed for 10 minutes. Other preparation conditions are the same as those of Example 1.

[0071] Comparative Example 3

[0072] Compared with Example 1, the difference of Comparative Example 3 is that in step (1), citric acid is added to adjust the pH value of the mixture to 2, and the other preparation conditions are the same as those of Example 1.

[0073] Comparative Example 4

[0074] Compared with Example 1, the difference of Comparative Example 4 is that in step (1), citric acid is added to adjust the pH value of the mixture to 6, and the other preparation conditions are the same as those of Example 1.

[0075] Test Example 1: Stability test of oyster sauce products

[0076] The oyster sauce products prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were tested for processing stability and shelf life stability:

[0077] The processing stability test and the shelf life stability test include the following tests:

[0078] 1. Viscosity test method: Under the condition of 25.0℃, weigh 100g of oyster sauce product into a 150ml beaker, adjust the liquid level of oyster sauce to the notch of the rotor, and use a BROOKFIED viscometer to test the viscosity of oyster sauce.

[0079] 2. Water extraction test method: Cool the oyster sauce that has undergone accelerated shelf life to room temperature, then tilt it at a 30° angle, peel the plastic beaker and straw together, accurately absorb the extracted water from the oyster sauce, and record the extracted water weight of different samples.

[0080] 3. Microscopic test method: Take an appropriate amount of oyster sauce product, dilute the oyster sauce by 5 times with water, disperse it into a uniform solution state, drop a drop of oyster sauce solution on a glass slide, add two drops of iodine solution, use a glass rod to stir evenly, cover with a coverslip, place the sample under the microscope objective, adjust the focus, and take pictures when clear starch granules can be seen in the eyepiece.

[0081] 4. Oyster sauce particle size test method: Take an appropriate amount of oyster sauce product, dilute the oyster sauce by 5 times with water, disperse it into a uniform solution state, add the sample into a laser particle size analyzer, make the sample's shading degree at 15%-20%, and test the volume-weighted particle size D10 of the oyster sauce (D10 means the cumulative percentage of particles less than or equal to this particle size accounts for 10%).

[0082] 5. Processing stability evaluation method of oyster sauce: Take 200g of oyster sauce product at 25.0℃, use IKAT25digital stirring disperser at the same height, adjust the shear speed to 8000rpm, shear for 2min, test the particle size of oyster sauce before and after shearing and observe the state of starch granules using a microscope.

[0083] The results are shown in Table 1.

[0084] Table 1

[0085]

[0086]

[0087] The results are shown in Table 1. Under the conditions of pH 4, 50°C warm treatment, 2000rpm, and shear emulsification for 10 minutes, the viscosity of the oyster sauce obtained by the modified starch-protein coupling treatment in Example 1 is moderate. After the processing stability test, the particle size of the oyster sauce D10 of Example 1 after shearing is reduced by 1.10μm (such as Figure 1-2 As shown), the particle size of the comparative example 1 decreased by 5.31 μm after shearing, compared with the oyster sauce of the comparative example 1 after shearing (as shown Figure 3-4 As shown in the figure, the particle size of the oyster sauce in Example 1 decreased by 4.21 μm, and the starch granules were relatively complete and swollen the least.

[0088] The viscosity of the oyster sauce obtained without heat treatment in Example 2 is close to that of the control. After the processing stability test, the particle size of the oyster sauce D10 is 2.69 μm lower than that of the oyster sauce D10 before shearing, which is slightly worse than that of Example 1 but better than that of Comparative Examples 1 to 4, and the starch particles are relatively intact.

[0089] The oyster sauce obtained by coupling modified starch-oyster juice at different pH (pH=3 or pH=5) in Example 3 and Example 4 has a viscosity close to that of the control. After the processing stability test, the particle size of the oyster sauce D10 after shearing is 3-3.5 μm lower than that of the oyster sauce D10 before shearing, and the starch granules are relatively complete, but slightly worse than Example 1 and better than Comparative Examples 1-4.

[0090] In Example 5, oyster sauce is obtained by coupling modified starch and oyster juice at different shear rates. The particle size of oyster sauce D10 after shearing is 3.13 μm lower than that before shearing. After the processing stability test, the oyster sauce starch particles are relatively complete, but slightly worse than Example 1 and better than Comparative Examples 1 to 4.

[0091] In Example 6, the oyster sauce obtained by extending the shear coupling time to 20 min has a particle size of oyster sauce D10 after shearing that is 3.6 μm lower than that of oyster sauce D10 before shearing, which is slightly worse than that of Example 1 but better than that of Comparative Examples 1 to 4. After the processing stability test, the oyster sauce starch particles are relatively intact;

[0092] Comparative Example 1: The oyster sauce obtained by the traditional oyster sauce cooking method has an initial D10 particle size smaller than that of Example 1. After shearing, the D10 particle size decreases by 5.31 μm, with the largest decrease in particle size. The oyster sauce of Comparative Example 1 is tested for processing resistance, and the starch granules are somewhat broken, and the integrity of the starch granules is inferior to that of Examples 1 to 6.

[0093] In comparative example 2, the oyster sauce was obtained without shear emulsification treatment. The particle size D10 of the oyster sauce after shearing was 4.36 μm smaller than that before shearing. After the processing stability test, the oyster sauce starch particles were broken to a certain extent.

[0094] Comparative Examples 3 and 4 are oyster sauces obtained by coupling modified starch-oyster juice at different pH values ​​(pH=2 or pH=6), wherein the viscosity of the oyster sauce in Comparative Example 3 with pH=2 is lower than that in Comparative Example 1, and after the processing stability test, the particle size of the oyster sauce D10 after shearing is 4.81 μm lower than that before shearing. After the processing resistance test, the starch granules of the oyster sauce in Comparative Example 3 are somewhat broken, and the integrity of the starch granules is not as good as that of Examples 1 to 6; after the processing stability test, the particle size of the oyster sauce D10 after shearing is 4.86 μm lower than that before shearing. After the processing resistance test, the starch granules of the oyster sauce in Comparative Example 4 are somewhat broken, and the integrity of the starch granules is not as good as that of Examples 1 to 6.

[0095] The oyster sauce products of Examples 1 to 6 and Comparative Examples 1 to 4 were selected for accelerated shelf life testing. The 6KG PE cans commonly used in the market were used for testing. The accelerated shelf life was tested for 30 days and 60 days in a 50°C constant temperature box, respectively. The results are shown in Table 2.

[0096] Table 2

[0097]

[0098] The results are shown in Table 2. Compared with Comparative Example 1, in Example 1, at an accelerated shelf life of 30 days, the amount of water precipitated from the oyster sauce was reduced by 16.82 g, and the rate of viscosity decrease of the oyster sauce was slowed by 32.57%. At an accelerated shelf life of 60 days, the amount of water precipitated from the oyster sauce was reduced by 24.95 g, and the rate of viscosity decrease of the oyster sauce was slowed by 55.40%.

[0099] Compared with the comparative example 1, the oyster sauce obtained in Example 2 without heat treatment has 13.19 g less water precipitation and 16.69% slower viscosity decrease rate after 30 days of accelerated shelf life; and 20.50 g less water precipitation and 47.97% slower viscosity decrease rate after 60 days of accelerated shelf life.

[0100] Compared with the comparative example 1, the oyster sauce obtained by coupling different pH values ​​(pH=3, or pH=5) in Example 3 and Example 4 has a reduced water precipitation of 14.65-15.93 g and a slowed viscosity decrease rate of 26.72-28.11% at an accelerated shelf life of 30 days. The water precipitation of oyster sauce is reduced by 20.93-21.72 g and a slowed viscosity decrease rate of 47.71-49.80% at an accelerated shelf life of 60 days.

[0101] In Example 5, the oyster sauce obtained by coupling modified starch-oyster juice at different shear rates is compared with the comparative example 1. After 30 days of accelerated shelf life, the water precipitation of oyster sauce is reduced by 12.56g, and the viscosity decrease rate of oyster sauce is delayed by 20.04%. After 60 days of accelerated shelf life, the water precipitation of oyster sauce is reduced by 20.02g, and the viscosity decrease rate of oyster sauce is delayed by 42.60%.

[0102] In Example 6, the oyster sauce obtained by extending the shear coupling time to 20 min is compared with that in Comparative Example 1. After 30 days of accelerated shelf life, the water precipitation of the oyster sauce is reduced by 10.92 g, and the viscosity decrease rate of the oyster sauce is delayed by 22.33%. After 60 days of accelerated shelf life, the water precipitation of the oyster sauce is reduced by 19.70 g, and the viscosity decrease rate of the oyster sauce is delayed by 43.07%.

[0103] In comparative example 1, the oyster sauce obtained by the traditional oyster sauce cooking method had 22.57 g of water separated out after 30 days of accelerated shelf life, and the viscosity of the oyster sauce decreased by 42.23%. The oyster sauce had the most water separated out and the viscosity of the oyster sauce decreased at the fastest rate. After 60 days of accelerated shelf life, the oyster sauce had 37.71 g of water separated out and the viscosity of the oyster sauce decreased by 78.28%. The oyster sauce had the most water separated out and the viscosity of the oyster sauce decreased at the fastest rate.

[0104] In Comparative Example 2, the oyster sauce obtained by not performing shear emulsification treatment had 7.93 g less water precipitation than that in Comparative Example 1 but 8.89 g more than that in Example 1 after an accelerated shelf life of 30 days, and the viscosity decrease rate of the oyster sauce was 16.76% slower than that in Comparative Example 1 but 15.81% faster than that in Example 1. At an accelerated shelf life of 60 days, the water precipitation of the oyster sauce was 12.27 g less than that in Comparative Example 1 but 12.68 g more than that in Example 1, and the viscosity decrease rate of the oyster sauce was 36.26% slower than that in Comparative Example 1 but 19.14% faster than that in Example 1.

[0105] Comparative Examples 3 and 4 are oyster sauces obtained by coupling modified starch-oyster juice at different pH values ​​(pH=2, or pH=6). After an accelerated shelf life of 30 days, the oyster sauce has 2.69-7.03 g less water than that of Comparative Example 1, but 9.79-14.13 g more water than that of Example 1. The rate of decrease in viscosity of the oyster sauce is 10.10-17.26% slower than that of Comparative Example 1 but 15.31-22.47% faster than that of Example 1. After an accelerated shelf life of 60 days, the oyster sauce has 4.30-10.68 g less water than that of Comparative Example 1 but 14.27-20.65 g more water than that of Example 1. The rate of decrease in viscosity of the oyster sauce is 7.62-34.10% slower than that of Comparative Example 1 but 21.30-47.78% faster than that of Example 1.

[0106] The results of microscopic examination of the initial sample of the oyster sauce in Example 1 and the starch granules in the oyster sauce in Example 1 after the accelerated shelf life of 60 days are as follows: Figure 5-6 shown.

[0107] The results of microscopic examination of the initial sample of the oyster sauce of comparative example 1 and the starch granules of the oyster sauce of comparative example 1 after accelerated shelf life of 60 days are as follows: Figure 7-Figure 8 shown.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

Claims

1. A method for improving the stability of modified starch in oyster sauce, characterized in that: The following steps are involved: S1, mixing modified starch, oyster juice and water to obtain a mixture, adjusting the pH value of the mixture to 3-5, and obtaining a treated mixture I; S2, shearing and emulsifying the treated mixture I to obtain a modified starch-protein complex; S3, mixing the seasoning and water to form a mixed solution, then adding the modified starch-protein complex to the mixed solution to obtain a mixture II, adjusting the pH value of the mixture II to 5.5-6.0, heating and keeping warm, and finally cooling and filling to obtain an oyster sauce product.

2. The method for improving the stability of modified starch in oyster sauce as claimed in claim 1, characterized in that: In the step S1, the mass ratio of modified starch, oyster juice and water is 1:(3-4):

2.

3. The method for improving the stability of modified starch in oyster sauce as claimed in claim 1, characterized in that: In the step S1, the temperature of the mixture is preheated to 45-55° C., and the insulation time is 10-20 minutes.

4. The method for improving the stability of modified starch in oyster sauce as claimed in claim 1, characterized in that: In step S1, the pH value of the mixture is adjusted to 4.

5. The method for improving the stability of modified starch in oyster sauce as claimed in claim 1, characterized in that: In the step S1, an acid solution is used to adjust the pH value of the mixture to 3 to 5; The acid includes citric acid.

6. The method for improving the stability of modified starch in oyster sauce as claimed in claim 1, characterized in that: In the step S2, the rotation speed of the shear emulsification is 2000-4000 rpm, and the time of the shear emulsification is 10-20 min.

7. The method for improving the stability of modified starch in oyster sauce as claimed in claim 6, characterized in that: In step S2, the rotation speed of the shear emulsification is 2000 rpm, and the time of the shear emulsification is 10 min.

8. The method for improving the stability of modified starch in oyster sauce as claimed in claim 1, characterized in that: In step S3, the seasonings include white sugar, edible salt, monosodium glutamate, caramel color, xanthan gum and potassium sorbate.

9. The method for improving the stability of modified starch in oyster sauce as claimed in claim 8, characterized in that: In the step S3, the mass ratio of seasoning, water and modified starch-protein complex is 20.8:(44.2-49.2):(30-35).

10. The method for improving the stability of modified starch in oyster sauce according to claim 1, characterized in that: In step S3, the heating and heat preservation conditions are: the temperature is 100° C., and the heat preservation time is 15 to 25 minutes; The cooling temperature is 60-70°C.

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