| Because the thermal stability and gelatability of minced freshwater fish products are much worse than that of Marine fish,there are many problems in the development and utilization of minced freshwater fish products.How to make better use of low-value freshwater fish has always been an important link to solve the bottleneck of freshwater fishery development in China.Silver carp,as an important large freshwater fish in China,is less popular than other large freshwater fish because of its many fish bones and fishy taste.It is the starting point of this experiment that how to make better use of the nutritional value of silver carp and improve the quality of its processed products.Myofibrin was treated with different methods?ultrasonic,transglutaminase?TG?and ultrasound-assisted TG enzyme?,and the effects of different treatment methods on myofibrin and gel functional characteristics of silver carp were studied.The experiment not only improved the physicochemical properties of myofibrin,but also improved the texture properties of fish ball products to a certain extent,and provided some theoretical basis for improving the quality of fresh water fish surimi processed products.The specific research results are as follows:?1?The effects of different treatment methods?ultrasonic treatment,TG enzyme treatment and ultrasound-assisted TG enzyme treatment?on the gel strength of silver carp myofibrin were studied.The gel strength was measured by texture apparatus.The results show that:Ultrasonic treatment:after optimization,the gel strength of silver carp myofibrin was 98.82 g.cm under the condition of 300 W ultrasonic power and 30 min ultrasonic time,which was 2.43 times higher than that of the blank group?gel strength?.TG enzyme treatment was added:orthogonal optimization results show that the TG enzyme content is 0.6%,40 min time of heat preservation,heat preservation temperature 40?,under the condition of pH 6.5,gel strength maximum right to 102.22 m,2.52 times higher than that of blank group gel strength.Ultrasound-assisted TG enzyme treatment:after box-behnken optimization,the results showed that under the conditions of TG enzyme content of 0.62%,ultrasonic time of 31 min,and ultrasonic power of 304 W,the maximum gel strength reached at this time was 151.427 g.cm,which was 3.73 times higher than the blank group.Comparative analysis determined that ultrasound-assisted TG enzymatic treatment was the best modification method.?2?The effects of different treatments on the functional characteristics of silver carp myofibrin were studied.The effects of different modification methods on the foaming property,emulsifying property,color group change,sulfhydryl content and protein denaturation temperature of silver carp myofibrin were studied by means of texture analyzer,uv spectrometer and DSC differential scanning calorimeter.The results showed that:a?foaming ability:compared with the blank group,the foaming ability of the modified group?ultrasonic treatment,TG enzyme addition treatment,and ultrasound-assisted TG enzyme treatment?was improved by 31%,20%,and 36%,respectively,and the effect of ultrasound-assisted TG enzyme treatment was better.Foam stability:the foam stability of the modified group was improved by 24%,18%and 35%,respectively.Emulsification properties:the modified group was improved by 24%,14%and17%,respectively.Emulsifying stability:TG enzyme treatment assisted by ultrasound has the best effect.b?Compared with the blank group,the untreated 55.359 umol/g pro,49.536 umol/g pro,and 35.524 umol/g pro in the ultrasonic treatment group,TG enzyme treatment group,and ultrasound-assisted TG enzyme treatment group decreased from 55.359 umol/g pro to 52.713umol/g pro,respectively.Ultrasound assisted TG enzyme treatment group had the most obvious effect.c?The ultraviolet absorbance of silver carp myofibrin solution was improved by modified treatment,and the ultrasound-assisted TG enzyme group was more obvious in different modification methods.The absorption peak is located near 220nm and 280nm,and there is an absorption peak near 280nm,which is due to the absorption of light by aromatic heterocycle such as tryptophan?Trp?and tyrosine?Tyr?.At about 220 nm there is a strong absorption peak caused by a c-o transition of the peptide bond.Compared with the blank group,the three modified groups had enhancement effect,and the absorption peak shifted slightly to the long wave direction,with a redshift trend.d?The thermal stability of modified protein was enhanced gradually.Compared with the blank group of thermal denaturation temperature of 79.3?,ultrasonic treatment group,TG enzyme treatment,ultrasonic aided thermal denaturation temperature TG enzyme treatment group were improved,were 81.6?,82.1?and 84.7?.The temperature of protein thermal denaturation was the highest after TG enzymatic treatment.?3?Effects of different treatments on the gelation characteristics of silver carp myofibrin were studied.The effects of different treatment methods on texture,whiteness,water retention,cooking loss and microstructure of silver carp fibrin gel were studied by means of texture meter,color difference meter and environmental scanning electron microscope.The results showed that:a?Hardness:the hardness of the modified gel was 30.28 g,56.44 g,and 78.26 g higher than that of the blank group,respectively.b?Elasticity:the gel elasticity treatment group was 0.23,0.12 and0.37 higher than the blank group,respectively.c?Whiteness:in the modified group,the highest whiteness value of the gel obtained by ultrasonic treatment was 33.27.However,the whiteness of the gel was reduced by adding TG enzyme from 28.31 to 27.40,and the whiteness of the gel obtained by ultrasound-assisted TG enzyme was 31.12.In the modified group,the ultrasonic treatment had the best effect,increasing by 17%.d?Hydrophobicity:compared with the blank group,the hydrophobicity of the gel in the modified group was increased by 20%by ultrasound treatment and 14%by ultrasound-assisted TG enzyme treatment,and the gel cooking loss was reduced by 8%by TG enzyme treatment.e?Cooking loss:the ultrasonic treatment in the modified treatment reduced the cooking loss of the gel to a certain extent.The addition of TG enzyme increased the cooking loss of the gel,which increased from 51.77%in the blank treatment to 57.39%.f?microstructure analysis,scanning electron microscope to observe by modification treatment samples and blank sample gel microscopic structure exists obvious difference,treatment group of samples in the enzyme catalysis and under the action of ultrasonic vibration due to the overlap between protein molecules in the aerogel effect to shorten the distance between each other,the gel surface is exquisite,more small and uniform mesh.The gel surface of blank treated samples was rough,and there were many irregular large holes,which were affected by the size of protein molecules.?4?The application and simple cost accounting of modified conditions in silver carp and fish pellets were studied.a?Box-behnken was used to optimize the formula of silver carp fish pellets,and the physical properties?hardness,elasticity,viscosity,chewiness?of modified silver carp fish pellets were compared and detected by using a property tester.The results showed that the best preparation formula of silver carp and fish ball was 1.4%salt,11.3%starch,6.7%egg white,1%monosodium glutamate,14%ice water,1.5%sugar,0.15%pepper and 0.3%ginger juice.Modification conditions:TG enzyme content was 0.62%,ultrasonic time was 31 min,and ultrasonic power was 304 W.b?After the formulation was optimized,the following results were obtained by comparing the non-modified fish pellet group?blank?,the ultrasonic treated fish pellet group?group A?,the tg-treated fish pellet group?group B?and the ultrasound-assisted tg-treated fish pellet group?group C?:Hardness:the best hardness of fish pellets in group C was28.83N·cm-2,which was 29%higher than the blank control group.Viscosity:the optimal viscosity of silver carp pellets in group A was 6.173 N,which was 31%higher than that in control group.Elasticity:the maximum elasticity of fish balls in group C was 2.14,which was57%higher than that in the blank group.Mastication:the best mastication of fish pellet in group C was 9.43 N·cm-2.25%higher than that in the blank group. |
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