The effects of storage on quality and nutritional values of Ehrenberg’s snapper muscles (Lutjanus ehrenbergi): Evaluation of natural antioxidants effect on the denaturation of proteins

Protein denaturation in frozen minced fillets (Ehrenberg’s Snapper), stored at −25°C was studied; 50.0 mg biomass/50g mince fillets treated with cinnamon, cumin, turmeric, garlic, ginger and 25.0 mg of vitamin C were used to slow protein denaturation. FT-IR stretching vibration of Amide-A (νNH) at 3300 cm⁻¹; Amide-I stretching (νC=O) between 1600−1690 cm⁻¹ and Amide-II stretching (νCN) and bending (δNH) between 1480 and 1575cm⁻¹ were used as marker peaks. Garlic was the most significant (P ≤0.01) in controlling the rate of protein denaturation when νNH was used as a marker peak. DSC analysis showed that turmeric presented the highest effect on delaying the denaturation of sarcoplasmic proteins with a ∆H⁰ =73.7J/g followed by garlic-treated mince fillets (∆H⁰ =70.1j/g). All spices used were efficient in stopping the denaturation of myosin with the highest ∆H⁰ = 769.3 j/g registered for cinnamon-treated mince fillets. Actin was less vulnerable to denaturation in comparison to myosin and sarcoplasmic proteins.