Study On Quality Change And Guarantee Technology Of Frozen Preserved Shrimp Surimi Of Penaeus Vannamei

The water retention characteristics of frozen Penaeus vannamei products are closely related to their quality.With the prolongation of frozen storage time,shrimp muscle protein undergoes freeze denaturation,tissue structure deterioration,juice loss,water content reduction,sensory properties and edible value reduction during thawing.How to improve the water retention of frozen prawns and their products and reduce the degree of frozen denaturation of proteins has always been a hot issue in the processing of shrimp aquatic products.In this paper,the frozen denaturation,oxidation and functional characteristics of protein in frozen shrimp meat surimi were studied by taking Penaeus vannamei as a control,and the effects and mechanisms of algin,algin oligosaccharide,carrageenan,carrageenan oligosaccharide and sodium pyrophosphate on the protein characteristics of frozen shrimp meat surimi were discussed,providing reference for improving the quality of frozen shrimp meat surimi and developing low sweetness,low calorie,natural and efficient quality assurance agents for shrimp products.The main research contents are as follows:1.The changes of protein physical and chemical properties of Penaeus vannamei surimi during frozen storage were studied with Penaeus vannamei kernel as control.Based on the analysis of pH value,water-soluble protein,salt-soluble protein,Ca²⁺-ATPase activity,total sulfhydryl group,active sulfhydryl group,chemical bonds and SDS-PAGE total protein of shrimp meat emulsion,the change rule of quality characteristics of shrimp meat emulsion during frozen storage for 120 days was explored.The results showed that the pH value of shrimp meat emulsion and shrimp meat gradually increased with the prolongation of frozen storage time,and the contents of water-soluble protein and salt-soluble protein,myofibrillar protein Ca²⁺-ATPase activity,total sulfhydryl group and active sulfhydryl group decreased continuously.In the process of frozen storage,combined with various determination indexes,it is found that the storage form of shrimp meat emulsion is better than the storage form of shrimp meat to ensure the quality.2.The structural changes of myofibrillar protein in Penaeus vannamei during frozen storage were studied with Penaeus vannamei kernel as control.Based on thermodynamic analysis,surface hydrophobicity,free amino acid,active sulfhydryl and carbonyl of myofibrillar protein,the changes of myofibrillar protein oxidation process during frozen storage of shrimp meat emulsion for 120 days were explored.The results showed that compared with the storage form of shrimp meat,the storage form of shrimp paste effectively inhibited the change of thermal stability of myofibrillar protein,slowed down the increase of carbonyl content and surface hydrophobicity,and inhibited the decrease of free amino acids in the meat paste.In addition,from the change of chemical bond content,the storage form of shrimp paste effectively inhibited the rapid decline of ionic bonds,hydrogen bonds and non-disulfide bonds,and delayed the increase of disulfide bond and hydrophobic bond content.Therefore,the storage form of shrimp paste is better than shrimp meat.3.The functional characteristics of myofibrillar protein of Penaeus vannamei during frozen storage were studied with Penaeus vannamei kernel as control.The changes of gel texture characteristics?hardness and elasticity?,gel water retention,solubility,turbidity of solution,emulsifying and emulsifying stability,foaming and foaming stability,secondary structure of myofibrillar protein were mainly studied.The results showed that during the frozen storage process,the gel characteristics analysis found that the elasticity and chewiness of the gel prepared from frozen shrimp meat were better than those of frozen shrimp meat,and the water retention of shrimp meat gel was also significantly better than that of shrimp meat.However,the solubility,turbidity,emulsification and foaming properties of shrimp paste are better than those of shrimp meat.From the above,the gel properties of shrimp paste during frozen storage need to be improved,while the data of other functional properties are better.4.The effects of algin,algin oligosaccharide,carrageenan,carrageenan oligosaccharide and sodium pyrophosphate on protein characteristics of white shrimp surimi during frozen storage were studied with blank shrimp surimi as control.The effects of different additives on the quality characteristics of shrimp mince were evaluated mainly through the analysis of myofibrillar protein content,myofibrillar fragmentation index,Ca²⁺-ATPase activity,secondary structure of myofibrillar protein,thermodynamic analysis of myofibrillar protein,SDS-PAGE analysis,free amino acid content,surface hydrophobicity,carbonyl content and other indicators.The results showed that the addition of alginate oligosaccharide,carrageenan oligosaccharide,carrageenan,alginate and sodium pyrophosphate could effectively slow down the decrease of myofibrillar protein content,Ca²⁺-ATPase activity,total sulfhydryl group and active sulfhydryl group content compared with the blank shrimp paste group,of which alginate oligosaccharide and carrageenan oligosaccharide had the best quality assurance effect.After frozen storage for 120d days,the surface hydrophobicity and carbonyl content of the shrimp paste treated with sugar addition are lower than those of the blank shrimp paste group,while the thermal stability is higher than that of the blank shrimp paste group.The results of free amino acid content and myofibril fragmentation index showed that shrimp surimi was also more stable after sugar treatment,among which carrageenan oligosaccharide and algin oligosaccharide had better frost resistance effect.From the secondary structure of protein,carrageenan and carrageenan oligosaccharide treated shrimp paste can more effectively alleviate the decrease of?-helix,?-fold,?-turn and random curl content.From gel electrophoresis,carrageenan oligosaccharide and algin oligo-treated shrimp paste can slow down the decomposition of protein to a certain extent and maintain the integrity of muscle protein.To sum up,saccharides can alleviate protein oxidation during freezing storage,and algin oligosaccharide and carrageenan oligosaccharide have more significant frost resistance.Therefore,carrageenan oligosaccharide and algin oligosaccharide can be applied to frozen aquatic products as low-sweetness and low-calorie phosphorus-free antifreeze agents.5.Taking fresh shrimps as control,the effects of distilled water soaking,5%trehalose soaking and 5%alginate oligosaccharide soaking on proteomics of Penaeus vannamei during frozen storage were studied.The composition of alginate oligosaccharide,trehalose and distilled water prawn muscle protein was mainly explored through quantitative ratio square distribution,sample expression pattern clustering,GO analysis,differential protein GO enrichment,Pathway metabolic pathway annotation,differential protein pathway enrichment,etc.The results showed that in the distribution of quantitative ratio straight square,the overall difference between alginate oligosaccharide,trehalose treatment and distilled water treatment was larger.From the cluster diagram of sample expression patterns,it was found that alginate oligosaccharide and distilled water treatment had a greater impact on the fifth type of differential proteins?see the text for details?.Trehalose and distilled water treatment groups have obvious differences in the group of category 5 and category 6 differential proteins.Compared with fresh shrimps,trehalose and algin oligosaccharide treated shrimps have significantly higher differential protein content than distilled water treated shrimps,and sugar treated samples are closer to the whole protein composition and content of fresh shrimps.Therefore,trehalose and algin oligosaccharide play a certain antifreeze protection role in the frozen storage process of shrimps.From the GO analysis chart,it can be seen that the difference between GO annotation protein results in distilled water group and fresh shrimps is the largest,and alginate oligosaccharide and trehalose treatment can effectively slow down the deterioration of shrimps proteome.Annotation map of Pathway metabolic pathway and enrichment map of differential protein pathway show that trehalose and algin oligosaccharide soaking treatment of shrimp meat is significantly better than distilled water soaking treatment in stability and protection of muscle protein.From above,through proteomic analysis,trehalose and algin oligosaccharide have good frost resistance and water retention effects.