Methodology Investigations for the Production of Amino Acid Hydrolysate From Shrimp Waste

Abstract

Various hydrolysis reaction conditions were examined in order to produce high quality hydrolysate from shrimp waste for its possible use in animal feed and some food products. In a first set of experiments, shrimp waste was hydrolysed with varying concentrations of HCl and samples taken after various hydrolysis times and tested for ninhydrin positive substances (NPS). Twelve hours of hydrolysis with 5N HCl gave maximum NPS yields and was, therefore, chosen as a suitable hydrolysing agent for subsequent hydrolysis trials.In a second set of experiments, shrimp waste samples of varying weights were hydrolysed with 5N HCl for various times and tested for NPS and total amino acids. On a dry weight basis, amino acid contents of all 12h hydrolysates varied from 29 to 35%. Maximum yields varying from 32 to 37% were achieved when the hydrolysis time was increased to 24h. Prolonging hydrolysis time to 48h reduced amino acid yields by 15–20 percent. The amino acid contents decreased with an increase in sample weight. Of the total amino acid contents approximately 40–42% were essential amino acids with considerable amounts of lysine, valine, leucine and threonine. The remaining 58–60% non-essential amino acid fraction was dominated by glutamic and aspartic acids.