Antioxidant Activity of Hybrid Sturgeon (<i>Huso dauricus</i> × <i>Acipenser schrenckii</i>) Protein Hydrolysate Prepared Using Bromelain, Its Fractions and Purified Peptides
Anwar Noman, Yuxia Wang, Chao Zhang, Sherif M. Abed
Abstract
Key words: hybrid sturgeon, enzymatic hydrolysis, hydrolysis optimization, bromelain, degree of hydrolysis, radical scavenging activity, peptide purification Protein hydrolysates could be a natural and safer source of antioxidant peptides. The purpose of this study was to optimize the hydrolysis of Huso dauricus Acipenser schrenckii sturgeon proteins using bromelain and purify antioxidant peptides from hydrolysate. The degree of hydrolysis of 18.69% was obtained under the optimal conditions and hydrolysate had 94.76% solubility, 902 nm particle size and high antioxidant activity. The IC 50 for DPPH and ABTS + scavenging activity were 3.14 and 3.81 mg/mL, respectively. The fraction of hydrolysate with a molecular weight of <1 kDa exhibited the highest antiradical activity against DPPH with IC 50 of 2.10 mg/mL. In turn, the IC 50 of the most active fraction after the Sephadex G-15 separation was 1.77 mg/mL. The reverse phase high performance liquid chromatography (RP-HPLC) was used to purify the peptides from this fraction. The peptide with histidine, leucine and glycine (MW of 0.2955 kDa) exhibited the highest antioxidant activity (IC 50 of 1.33 mg/mL). The obtained fractions and peptides with antioxidant activity could be used as natural substitutes for synthetic antioxidants, especially in food and pharmaceuticals.