Research On Compound Preservation Technology Of Fresh Keeping Grass Carp And Fish Ball Processing Technique

China is endowed with rich aquatic resources,and the yield of grass carp as one of major cultivated freshwater fishes is on the increase day by da y.The dissertation takes grass carp as research object,which contains abundant quality protein and has becomes one of major fishes consumed by Chinese people in C hina.However,grass carp has some shortcomings such as loose texture,large moisture content,easy degradation,low gel strength and heavy earth smell,restricting its sales and development as well as its processed products.Therefore,effective preservation technology is needed to preserve and process fresh grass carp to enlarge its sales scope and extend its sale period.The study focuses on quality change of frozen grass carp after unfreezing and selects the optimal thawing method,paving the way for minced fillet processing with frozen fishes as raw materials.Conclusion of the research are mainly presented in three aspects as follows:1.The present research adopts grass carp as raw material,and selects three kinds of phosphates(sodium pyrophosphate,sodium tripolyphosphate and sodium hexametaphosphate)as research object.Orthogonal experiment is conducted to determine that the optimal ratio of composite phosphate preservative is 2:1:1,the optimal additive amount is 0.3% and fish flesh has the optimal water-retaining property under such ration and additive amount.The experiment is conducted to measure its pH change,volatile base nitrogen content,total number of bacteria,value of chromatism and sensory score.The research results show that addition of composite phosphate as preservative can postpone the speed of fish flesh going bad,control the increase of p H value of fish flesh,slow down the increase speed of volatile base nitrogen content and restrict the increase of bacterial in fish flesh to some degree.2.Water thawing,refrigerator thawing,water bath thawing,air thawing and microwave thawing are adopted to study and contrast fish quality changes of frozen fish with r different thawing methods.Various indicators are synthesized to find that microwave thawing is a better option to effectively recover frozen fish flesh regardless of preservation of drip loss(2.21%)and pH(6.5)or content of total bacterial(0.435lgCFU/g)compared with other thawing methods,which brings about the minimum microbial contamination,fast thawing speed,good thawing quality and less loss of color,fragrance and taste.3.In order to enhance fish ball quality of grass ca rp and add flavor to fish ball,several auxiliary materials and quality improvers are added.Sensory score of products by means of single factor and orthogonal experiment shows that the optima l additive amounts in fish ball of grass carp are 8% celery and mushroom puree,12% corn starch,5% pig fat and 4% quality improver.Fish ball with such formula is equipped with unique flavor,excellent nutrition and optimal quality.