Abstract: Zein was hydrolyzed by trypsin and papain separately, and the antioxidant, antibacterial and emulsifying activities of the hydrolysates were analyzed. The papain hydrolyste fractions with good antioxidant, antibacterial and emulsifying activities were further purified using an ?KTA protein purification system and reversed-phase high performance liquid chromatography (RP-HPLC). Using matrix-assisted laser desorption/ionization quadrupole time-of-flight mass spectrometry, the amino acid sequence of the purified peptide was determined to be LLAH. The natural and synthetic LLAHs showed comparable scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) cation radical, iron ion reducing power and emulsifying ability. Both LLAHs could inhibit the growth of Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Listeria monocytogenes. The average particle size of LLAH stabilized emulsion was (263.4 ± 3.5) nm, which was lower than that of Tween-80 stabilized emulsion ((286.8 ± 3.5) nm). The storage and oxidation stability of the former were higher than those of the latter. LLAH stabilized emulsion exerted antibacterial effects against the tested strains. The antibacterial and antioxidant activities of LLAH could make a positive contribution to the stability of the emulsion. The results of this study will provide valuable information for the development of novel zein peptide-based functional foods.

Key words: antioxidant activity; antibacterial activity; zein peptides; emulsion