Optimization of enzymatic hydrolysis of collagen from yellowfin tuna skin ( Thunnus albacares ) by response surface methodology and properties of hydrolyzed collagen

Response surface methodology was used to optimize hydrolysis conditions of collagen from yellowfin tuna skin (Thunnus albacares) for maximizing the degree of hydrolysis (DH) and nitrogen recovery efficiency (NR). The results showed that the optimum hydrolysis parameters were at 54.7°C and pH 8 with 0.034 AU/g alcalase concentration for 5.2 hr. The predicted DH and NR under optimal conditions were validated and confirmed as 24.51% and 96.35%, respectively. The obtained collagen hydrolysate (CH) was rich in proline, glycine, methionine, and hydroxyproline residues. The antioxidation and antifreezing activity of CH were identified as 2,2-diphenyl-1-picrylhydrazyl radical activity (IC50 77.04 µg/ml), and hydroxyl radical activity (IC50 36.59 µg/ml). It also exhibited antifreezing property and had the inhibition rate of peroxide value of oil up to 73.53%. The results suggested that CH from yellowfin tuna skin could be used in the production of functional food products or other related industries. Practical applications Due to its low solubility, collagen has limited applications in industry. This study aimed to optimize the hydrolysis conditions of the collagen from yellowfin tuna skin in order to apply in industry. The collagen hydrolysate which is rich in proline, glycine, methionine, and hydroxyproline residues has excellent antioxidant, antifreezing, and antioxidation properties. Collagen hydrolysate can be used in the production of food and functional food products or other related industries due to excellent antioxidant and antifreezing properties, and good inhibition rate of oil oxidation.