High Value Comprehensive Utilization Of Freshwater Fish Processing By-Products

As a super country in freshwater fishery, China is rich in scaly fish species and shellfish aquatic products such as Procambarus clarkii. With the development of freshwater fish processing industry, scale, shrimp hepatopancreas and other processing by-product production continues to grow, its rich nutrition and high potential value, but did not get effective use, this creates a huge waste of resources. In this thesis, we studied on fresh water scales and Procambarus clarkii hepatopancreas comprehensive utilization respectively. At first, we use scales as raw materials, combinate three traditional methods of gelatin extraction, discussed the best process of acid and alkali in combination with hot water boil extracted fish scale gelatin, developed and characterized a new type of fish gel food with extracted scale gelatin. Then, use hepatopancreas as raw materials, analysis of the nutrients application ofprecolumn derivatization RP-HPLCand GC-MS methods.Combinate acid, alkali and hot water boil extracted fish scale gelatin, with gelatin yield as index, the best process conditions are:different concentration of hydrochloric acid treated8.53h, liming7.36d,80.4℃, pH5-6boiling4.25h, gelatin highest yield is30.56%。Three flavors fish gel formula is:saline taste (3%carrageenan,2%salt,2%vinegar,0.1%sauce,2%ginger,1%garlic,1%onion and0.1%Chinese prickly ash); fruity taste (white granulated sugar4%, citric acid2%, apple juice10%); milky taste (white granulated sugar4%, cream0.5%, milk30%). With reference to national edible gelatin industry standards, characterized the fish gel food: moisture9.0%, ash content1.6%, the1%solution pH5.2, Pb0.128ug/ml, Cr0.42ug/ml,90℃autoclaving, total plate count220cfu/g, coli group and salmonella has not been detected, all the indexes accord with standard, belongs to the qualified products. Nutritional analysis show that:the fat content in the raw material is50.46%, detected a total of14kinds of fatty acids (Myristic acid, Pentadecanoic acid, Nonanedioic acid, Hexadecanoic acid,9-Hexadecanoic acid, Stearic acid,9-Octadecenoic acid,9,12-Octadecenoic acid,9,12,15-Octadecenoic acid, Nonadecanoate, etc.), among them the content of unsaturated fatty acid is about52.55%, furthermore detected the squalene, a kind of important triterpene substances; In hydrolysate sample,17kinds of amino acids were all found in the crawfish hepatopancreas, the amounts of total amino acids are328.2mg/g fresh weight, the essential amino acid accounted for about23.54%, the amounts of total free amino acids are135.7mg/g fresh weight, the main contribution to crawfish hepatopancreas flavor amino acids in the order of Ala, Glu, Arg, Asp, Gly, contents of45,26.5,14.1,12.3,10.3mg/g respectively; Overall,50volatile components were determined, including alcohols compound6,18kinds of aldehyde compounds, ketone compounds4,14kinds of hydrocarbon compounds,3kinds of ester compounds, nitrogen containing sulfur compounds and other4, these volatile material combination was assigned to the crayfish hepatopancreas unique fresh fragrance.The research based on two kinds of freshwater fish processing by-products, developed a new type of fish gel products, analysed the crayfish hepatopancreas nutrient profiles, for development of new type seasoning provides an important theoretical basis.