Study on utilization of shrimp wastes products
1994
Piangchai Hanwatanawuthi
Waste products from sea food processing industries are consisted head and shell portions. The percentage of head, shell and meat portion of black-tiger prawn are 38, 7 and 55 percent respectively. Shimp waste products contain 63.8 percent protein, 1.73 percent fat and chitin/chitosan. Chemical composition depend on age of shrimp especially fat content. The rest are chitin and chitosan. The compositions of put protein and lipids vary with age in particaly fat content, it increase from 1.5 percent in 1 month old prawn to 3.4-4.5 percent in the fully grown prawn. The process to utilize these waste product or the combination enzymatic hydrolysis combined with solvent extraction and alkali/acid extraction to recover proteins and amino acids, fats and chitin/chitosan. This study shows that raw shrimp waste is readily digested by the enzyme protease that the cooked shrimp waste. The hydrolysis in a pilot scale reactor with 9 % neutrase or 2.85*10** (5) CDU/kg shrimp was at 50 deg C and the pH is controlled at 7 with 5N hydrochloric acid and soluble protein are increased from 3.8 to 5.96 percent in three hours: The soluble protein was increased by 53.8 percent compared with 39.6 percent in using cooked waste product. These condition is the best condition compared to the hydrolysis with 3, 6 and 12 percent enzyme with only 33.7, 36.6 and 51.3 percent increase of protein in the extract. The performance of enzymatic hydrolysis is greatly improved neutrase was replaced with koji protease of Aspergillus oryzae. The main amino acids in shrimp waste hydrolysates are aspartic and glutamic acid, lysine and alanine. They are present at the level suitable to be used for formulation shrimp sauces seasoning and shrimp protein powders. The solid portion contain about 35 percent fat after extraction with hexane, the rest are chitin and chitosan with the yield of 2.48 and 2.09 percent respectively.
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