Application Of Waste Of Roasted Eel

The eel is a famal economic aquatic. It is used to be considered an invigorant. Its meat, bone, blood, and fat are all used to officinal in medicine in China. The product of roasted eel is an aquatic product which has high nutrition and economic value. A great lot of these products were exported from many provinces along to sea in China. During the processing of the roasted eel, a lot of by-products were produced, such as the fat, head, bone, and meat. All these by-products were not made full use of, except the fat and bone. A great quantity of nutritional ingredients of its head and meat cling to it were wasted.The hydrolytic protein is a studied hotspot in recent years. It has a virtue in both nutrition and health protection. A lot of studies indicated that the hydrolytic fish protein could restrain the disease of high fat in blood caused by diabetes and alleviate symptom of high blood pressure. It could also adjust water in skin.the hydrolytic fish protein was prepared by enzymatic methods from the head of eel. The optimal conditions of enzymatic hydrolyze were discussed, such as temperature, pH, enzyme amount, enzyme variety, reaction time. The infections of enzymatic conditions on the gain ratio, and the extent of enzymatic hydrolysis, and the content of amino acid were discussed. The nutritional composition of enzymatic hydrolytic fish protein was analyzed. A solution way to use of the resources of the eel waste and to decrease environmental pollution was provided. Some science basis for finding a new approach into deep processing of by-product was also provided.The optimal conditions for preparation of hydrolytic fish protein with flavourzyme, protamex, trypsin were following:(1 )The optimal hydrolytic conditions with flavourzyme were : pH 5.5, enzyme amount 400u/g, temperature 55°C and hydrolysis time 6h; (2) The optimal hydrolytic conditions with protamex were : pH 6.0, enzyme amount 600u/g, temperature 55°C and hydrolysis time 5h; (3) The optimal hydrolytic conditions with trypsin were : pH 7.0. enzyme amount 1040u/g, temperature 45°C and hydrolysis time 6h. The content of crude protein in fish protein hydrolysate with flavourzyme amounted to 63.97%, and the content of amino nitrogen was 3.01%, and the gain ratio was 36.4%. The content of crude protein in fish protein hydrolysate with protamex amounted to89.28%, and the content of amino nitrogen was 2.82%, and the gain ratio was 43.41%. The content of crude protein in fish protein hydrolysate with trypsin amounted to 61.87%, and the content of amino nitrogen was 2.55%, and the gain ratio was 47.88%. The content of fat in those fish protein hydrolysate was lower than 0.2%, because the fat in the head of eelwas removed before hydrolysis. So that, we could conclude the best enzyme was protamex.Papain was extracted from latex in green pawpaw by ethanol. It is white powder,with good solubility. The gain ratio of crude papain was 36.54%. The enzymatic activity of papain by Folin-hydroxybenzene method was 3.15x105u/go The enzymatic activity of papain was affected by several factors, such as temperature, pH, concentration of substrate or papain or product, et al. The temperature and the pH strongly affected the enzymatic activity; and the optimal temperature and pH of papain were 80°C and 7.0, respectively. So papain was hot stable.The technology of hydrolyzing the head of eel with papain to prepare fish protein hydrolysate was discussed, and the best hydrolytic condition was following : pH7.0i temperature 70°C, concentrate of substrate l:IO(solid: liquid), enzyme amount 4500u/g, and reaction time 4h? At those optimal hydrolytic conditions, the degree of hydrolysis of protein was up to 22.7%, the recovery of nitrogen was up to86.17%, the average peptide chain offish protein hydrolysate was 4.4, and the gain ratio was up to 63.18%. The fish protein hydrolysate with papain was shaped light-yellow powder. It was clear in solution. The nutritional analysis results of the fish protein hydrolysate were following: the content of water was 6.88%, the content of crude protein was 88.52%, the content of dissociative amino-nitrogen was 3.2%, the content of ashes was 5.8%, the content of Pb was 1.2mg/kg. the content of As was O.33mg/kg, the content of Hg was 0.14mg/kg. Papain was the best enzyme for producing the fish protein hydrolysate, comparing with above three forenamed enzymes.The drying method had strong infection on the quality of the fish protein hydrolysate. The quality of the fish protein hydrolysate was deteriorated, with oven drying. The color was dark, and its solution was cloudy, comparing with free-drying, The quality of the product could be improved within removing the fat of the material. The fish protein hydrolysate produced by material without fat had good color and flavor, its solution was clearer. The content of amino acid, and the gain ratio, and the effect of hydrolysis of product were satisfaction. So, high quality protein hydrolysate could be hold with free-drying and fatless crude materials.The distributing of amino acid in the fish protein hydrolysate with papain was following: the total acid was 879.23mg/g, the essential amino acid amount to 233.36mg/gi the content of essential amino acid in total amino acid was 26.5%. the...