Effects of High-Pressure Treatments (Ultra-High Hydrostatic Pressure and High-Pressure Homogenization) on Bighead Carp (Aristichthys nobilis) Myofibrillar Protein Native State and Its Hydrolysate

The impacts of four treatments, ultra-high hydrostatic pressure (UHP), high-pressure homogenization (HPH), combined UHP + HPH (U-H), and HPH + UHP (H-U), on bighead carp (Aristichthys nobilis) myofibrillar protein (BMP) structure, functional hydrolysis property to pepsin, and antioxidant activity of hydrolysates were investigated. All treatments led to increase in low-molecular-weight BMP, the BMP stability, and hydrophobic group exposure, but decrease in total sulfhydryl content and BMP particle size, thus resulting in increased hydrolysis and antioxidant capacity of enzymatic hydrolysates. U-H treated BMP exhibited the highest surface hydrophobicity (924.5 ± 1.0), zeta potential absolute value (18.88 ± 0.11 mV), hydrolysis degree (54.5 ± 1.6%), and antioxidant activity, but the lowest α-helix (21.84 ± 2.61%), intrinsic fluorescence spectrum intensity, total sulfhydryl (7.24 ± 0.07 μmol/g), and mean particle size (182.57 ± 2.23 nm). Therefore, U-H might be a promising pretreatment to prepare bioactive peptide.