Effect of hydrolysis status on nitrogen recovery and molecular weight of protein from yellow fin tuna(Thunus albacara) head by alcalase

Tuna canning processing generates solid by-products, constituting 50- 70% of the original raw material. The main aim behind the hydrolysis of fish byproduct is to achieve a valuable material with high efficiency and quality. The objectives of this study were to optimize process conditions of fish proteins hydrolysate (due to its various application in food industries).Enzymatic hydrolysis of Yellow fin tuna head has been conducted by Alcalase with three replications using an experimental design. The hydrolysis conditions were (temperature: 55ºC, pH= 8.5, enzymatic activity 35Au ⁄ Kg and three consecutive time of 10, 20 and 30 minutes). The efficiency of protein production, degree of hydrolysis, the peptide chain length and electrophoresis pattern were evaluated. The results showed that increasing in time of protein hydrolysis causes an increase in efficiency of protein production and degree of hydrolysis and decreasing of peptide chain length. Among the above three mentioned times, 30 minute, with highest degree of hydrolysis is considered the best time for Alcalase enzyme. The most recovery of protein and degree of hydrolysis is related to first stage of hydrolysis (p˂0.01). In a study pertained to Electrophoresis pattern by SDS- PAGE, molecular weight of the most proteins hydrolysate had been about 12 KD.