Effect of High Voltage Pulsed Electric Field Pretreatment on the Biological Activity and Enzymolysis of Phosvitin from Black Carp Roe

The effects of assisted extraction with high voltage pulsed electric field (PEF) of phosvitin (Pv) from black carp roe on extraction rate, protein structure, physicochemical properties, antioxidant activity, degree of enzymatic hydrolysis, and antioxidant activity were investigated. The number of pulses and the electric field intensity were varied. Compared to the untreated sample, when the pulse number was 12 and the electric field intensity was 20 kV/cm, the extraction rate of Pv was increased by 1.10%, and the emulsification activity and emulsion stability increased to 22.15 m²/g and 54.02%, which was 2.95 m²/g and 4.84%, respectively. The denaturation temperature of Pv decreased from 118.33 to 103.78 ℃, and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability and Fe²⁺ ion chelating ability increased to 45.38% and 74.30%, which were 2.02% and 7.64% higher, respectively. Meanwhile, the molecular weight and the number of subunits of Pv were unchanged, and the secondary structure changed from β-sheet to random coil and β-turn. Scanning electron microscopic analysis showed that the application of PEF did not damage the Pv surface. After assisted extraction with PEF, Pv was hydrolyzed by alkaline protease and trypsin to obtain phosphopeptides (PP), with a degree of hydrolysis of 39.03 ± 0.28%, total antioxidant capacity of 263.16 ± 17.19 µmol/100 mg, Fe²⁺ chelating ability of 86.86 ± 1.66%, and the surface hydrophobicity was enhanced. All these values were significantly higher than the untreated group, facilitating the chelation of PP with metal ions to produce metal ion bio-supplements. The relationship between the structural changes and functions of Pv after assisted extraction with PEF was elucidated.