Production, identification and characterization of antioxidant peptides from potato protein by energy-divergent and gathered ultrasound assisted enzymatic hydrolysis

Effects of energy divergent ultrasound (EDU, 30, 40 and 50 W/L) and energy gathered ultrasound (EGU)-assisted enzymatic hydrolysis on production, identification and characterization of antioxidant peptides from potato protein hydrolysates (PPH) were investigated. EDU and EGU significantly increased degree of hydrolysis and recovery of PPH compared with conventional (C) enzymatic hydrolysis. PPH by EGU40 showed the highest Fe2+-chelating activity (55.33 µg EDTA/mL), ·OH scavenging activity (230.05 µg Vc/mL) and oxygen radical absorbance capacity (82.24 µg TE/mL). Peptides with molecular weight <1 and 1–2 kDa of PPH by EGU40 displayed higher antioxidant activities than those by C and EDU40, which might be contributed to their more hydrophobic, polar charged and antioxidant amino acids at terminals and/or inside the sequences identified by LC-MS/MS. Additionally, structure–activity relationship was revealed by peptide conformation and position of some specific amino acids. Therefore, EGU has great potential in production of functional peptides with enhanced antioxidant activity.