title: Reducing, radical scavenging, and chelation properties of in vitro digests of alcalase-treated zein hydrolysate.
abstract: The objective of the study was to assess the antioxidant potential of alcalase-treated zein hydrolysate (ZH) during a two-stage (1 h of pepsin --> 0.5-2 h of pancreatin, 37 degrees C) in vitro digestion. Sephadex gel filtration and high-performance size exclusion chromatography were used to separate ZH into fractions. The amino acid composition, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+*)) and 1,1-diphenyl-2-picrylhydrazyl (DPPH*) free radical scavenging activity, reducing power, and Cu (2+) chelation ability were tested to determine the antioxidant efficacy of ZH. Results showed that in vitro digests of ZH contained up to 16.5% free amino acids, with short peptides (<500 Da) making up the rest of the mass. The ABTS(+*) scavenging activity of ZH was decreased by 27% (P<0.05) after pepsin treatment but was fully recovered upon subsequent pancreatin digestion, while the DPPH* scavenging activity of ZH was substantially less than ABTS(+*) scavenging activity and showed a 7-fold reduction following pancreatin treatment. The reducing power of ZH increased 2-fold (P<0.05) following pancreatin digestion when compared with nondigested ZH. The ability of ZH to sequester Cu (2+) was reduced by pepsin digestion but was reestablished following pancreatin treatment. The antioxidant activity demonstrated by in vitro digests of ZH (1-8 mg/mL) was comparable to or exceeded (P<0.05) that of 0.1 mg/mL of ascorbic acid or BHA. The results suggested that dietary zein alcalase hydrolysate may have the benefit to promote the health of the human digestive tract.
authors: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
authors: Lijuan
authors: L
authors: Zhu
authors: Jie
authors: J
authors: Chen
authors: Xueyan
authors: X
authors: Tang
authors: Youling L
authors: YL
authors: Xiong
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D004063:Digestion; D016166:Free Radical Scavengers / Q000737:chemistry*; D010084:Oxidation-Reduction; D011492:Protein Hydrolysates / Q000737:chemistry*; D013381:Subtilisins / Q000378:metabolism*; D015028:Zein / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D016166:Free Radical Scavengers; D011492:Protein Hydrolysates; D015028:Zein; D013381:Subtilisins