Evaluation of functional properties of bioactive peptides produced from shrimp wastes in processing centers using protamex enzyme in different degrees of hydrolysis

The aim of this study was to investigate the functional properties of bioactive peptides produced from shrimp wastes in processing centers in three degrees of hydrolysis. For this purpose, the wastes of shrimp processing centers were hydrolyzed in three times of one, two and three hours using protamex enzyme and the functional properties of the resulting peptides (SPH₁, SPH₂ and SPH₃) were evaluated. The results showed that with increasing the hydrolysis time from one to two and three hours, the degree of hydrolysis and nitrogen recovery of the process increased significantly (p<0.05). According to the findings, the solubility of SPH₃ was significantly higher than SPH₁ and SPH₂ and its maximum was reported at pH=10, equal to 97.82±1.54% (p<0.05). SPH₁ had higher emulsifying activity and emulsion stability index than SPH₂ and SPH₃. In this peptide, the highest value of emulsifying activity index was reported 68.15±2.84 m²/g, which was related to pH=10. But the maximum emulsion stability index was reported at pH=6 (166.84±5.08 minute). The highest measured foaming activity was 165.52±5.91% which was recorded at SPH₁ and pH=10. Also, the maximum foam stability among the peptides was measured 118.32±3.23%, which was related to SPH₁ at pH=6. SPH₁ had a higher oil absorption capacity (5.92±0.33 ml/g) than SPH₂ and SPH₃ (p<0.05). The highest water holding capacity (5.18±0.71 ml/g) was related to SPH₃ (p<0.05). According to the findings, the functional properties of peptides produced from wastes of shrimp processing centers using protamax enzyme are at an acceptable level for use in various foods.