Precipitation of protein, proximate analysis and amino acid composition of waste effluent of prawn processing

The precipitation of protein from waste water of shrimp processing was done by changing the ph from 9.2 to ph 3.0, 4.0, 5.0, 6.0, 7.0 and 8.0 with 4 n hci. the precipitation of protein at ph 4.0 gave the highest amount of precipitate as well as the highest crude protein content. proximate analysis of the precipitate indicated the presence of 77.7% crude protein, 16.9% crude fat, 2.73% ash and 1.42% moisture on dry weight basis. the hplc analysis indicated the presence of 18 amino acids (asp, glu, ser, thr, arg, gly, ala, pro, val, met, leu, ile, phe, cys, lys, his, trp and tyr) in the precipitate. the total amount of free amino acids in the precipitate was 80.04 g ± 0.97/100 g samples with glutamic acid being the most abundant. amino acid analysis also indicated that the precipitate contained high amount of essential amino acids (43.72%).