Investigation of Antimicrobial Activity and Properties of Hydrolyzed Indian Mackerel Waste Proteins Using Commercial Enzymes

In this study, Indian mackerel (Rastrelliger kanagurta ) waste protein hydrolysate was produced using two enzymes, alcalase and flavourzyme, at different times of hydrolysis (10, 20 and 30 minutes) and then its antimicrobial properties against Gram-positive Escherichia coli and Gram-negative Staphylococcus aurous were examined. The results showed that the highest values of nitrogen recovery (89.88%) and degree of hydrolysis (38.70%) were observed by alcalase enzyme during 30 minutes of hydrolysis (P <0.05). The composition of amino acids also showed that the proteins hydrolyzed with both enzymes have a relatively similar composition. The highest levels of essential amino acids for alcalase and flavourzyme were lysine 7.99%, 7.19% and arginine 7.55% and 8.21%, respectively. The highest levels of non- essential amino acids were glutamic acid 12.55%, 11.79% and then aspartic amino acid were 7.99% and 6.98%, respectively. The chemical index showed that both hydrolyzed proteins could well meet an adult human need for most amino acids. The highest antimicrobial activity was observed in the hydrolyzed protein produced by alcalase (P <0.05). Staphylococcus aureus had lower resistance to Escherichia coli. Overall, it seems that Indian mackerel waste protein hydrolysate can be used as protein supplements in food and in diet formulas as a natural antimicrobial.