Investigation On Lipid Quality Changes Of Several Aquatic Products During Processing And Storage

Many coastal enterprises in China use local materials to make oily semi-solid composite seasoning from seafood that is inconvenient for storage and transportation.Because the industrial production technology requirements of this kind of seasoning are low,the strength of the production enterprises is uneven.Now the standards for such products are very broad,and the quality of products produced by different enterprises varies greatly.Therefore,it is particularly important to study the changes of product quality in the production and processing of this kind of seasoning.In this paper,shrimp skin sauce,laver sauce and scallop sauce were used to study the changing trend of lipids in the production and processing of this kind of aquatic compound seasoning,a compound antioxidant suitable for this kind of products designed,the sterilization process of the products optimized,and the shelf life of the optimized products was verified.The results are as follows:(1)The lipid changes of shrimp paste during processing were studied.The results showed that the dilution of ingredients in the preparation of shrimp paste significantly reduced the indexes of total fat,triglyceride,cholesterol,malondialdehyde,acid value and peroxide value(P<0.05);The content of triglyceride and peroxide value decreased significantly(P<0.05),while the content of cholesterol,malondialdehyde and acid value increased significantly(P<0.05);Sterilization resulted in a significant increase in the acid value of the material(P<0.05),but had no significant effect on the peroxide value(P>0.05).Based on the material quality,the optimal formula of compound antioxidant is:0.15g/kg rosemary+0.037g/kg edta-2na+0.2g/kg ve.At the same time,the compound antioxidant and single antioxidant were tested for accelerated oxidation.The antioxidant effect of shrimp paste was follows:compound antioxidant>ve>rosemary>edta-2na>blank.(2)The optimum processing parameters of two processing technologies of shrimp skin sauce were obtained.The results showed that the first processing technical parameter was that the product was pasteurized at(20min+85℃)after adding(0.974g/kg preservative potassium sorbate+0.387g/kg compound antioxidant).The second processing technical parameter is:the product is sterilized at high temperature(20min+117℃)after adding(0.377g/kg compound antioxidant+0.974g/kg preservative potassium sorbate).The fatty acid composition of pasteurized and high temperature sterilized shrimp paste was studied.It was found that shrimp paste contained 12 fatty acid components.After sterilization,four fatty acids changed most significantly(P<0.05),namely tetradecanoic acid,heptadecanoic acid,stearic acid and arachidonic acid.Tetradecanoic acid has an obvious upward trend in pasteurization process,while it has an obvious decrease in high-temperature sterilization process.It is inferred that tetradecanoic acid is easy to produce decomposition reaction at high temperature.Heptadecanoic acid decreased signficantly in both pasteurization and high temperature sterilization processes.Stearic acid showed a signficant increase trend in sterilization.Arachidonic acid had no significant change in pasteurization process,but increased signficantly in high temperature sterilization process.The shelf life of shrimp paste with different sterilization methods was studied.It was found that the shelf life of pasteurized shrimp paste increased from 133 days to 394 days,an increase of 1.96 times.The shelf life of high-temperature sterilized shrimp paste increased from 127 days to 383 days,an increase of 2.02 times.(3)The application effect of compound antioxidants in laver sauce and scallop sauce was studied.The results showed that the use of compound antioxidants could reduce the increase of acid value and peroxide value of laver sauce and scallop sauce caused by sterilization technology,and AV and POV decreased significantly after use(P<0.05).The color protection effect of compound antioxidants on laver sauce and scallop sauce was studied.It was found that 1 value and b value had no significant change(P>0.05),and a value had significant change(P<0.05).The L value,a value and b value of scallop sauce changed significantly(P<0.05).The shelf life of laver sauce and scallop sauce after using complex antioxidants was stodied.It was found that after adding antioxidants,the shelf life of pasteurized laver sauce was 301 days,that of high-temperature sterilized laver sauce was 255 days,that of pasteurized scallop sauce was 305 days,and that of high-temperature sterilized scallop sauce was 264 days.The shelf life of pasteurized products is 41-46 days longer than that of high-temperature sterilized products,indicating that pasteurized products can better store such products under the condition of good microbial index control and compounding relevant national standards.This thesis has 33 figures,44 tables and 100 references.