Rice proteins, extracted by alkali and alpha-amylase, differently affect in vitro antioxidant activity

卷:206

Wang, Zhengxuan ; Liu, Ye ; Li, Hui ; Yang, Lin

Harbin Inst Technol

关键词: Rice protein;    Antioxidant activity;    Alkali treatment;    alpha-Amylase degradation;   

DOI  :  10.1016/j.foodchem.2016.03.042

学科分类：食品科学和技术

【 摘 要 】

Alkali treatment and alpha-amylase degradation are different processes for rice protein (RP) isolation. The major aim of this study was to determine the influence of two different extraction methods on the antioxidant capacities of RPA, extracted by alkaline (0.2% NaOH), and RPE, extracted by alpha-amylase, during in vitro digestion for 2 h with pepsin and for 3 h with pancreatin. Upon pepsin-pancreatin digestion, the protein hydrolysates (RPA-S, RPE-S), which were the supernatants in the absence of undigested residue, and the whole protein digests (RPA, RPE), in which undigested residue remained, were measured. RPE exhibited the stronger antioxidant responses to free radical scavenging activity, metal chelating activity, and reducing power, whereas the weakest antioxidant capacities were produced by RPE-S. In contrast, no significant differences in antioxidant activity were observed between RPA and RPA-S. The present study demonstrated that the in vitro antioxidant responses induced by the hydrolysates and the protein digests of RPs could be affected differently by alkali treatment and alpha-amylase degradation, suggesting that the extraction is a vital processing step to modify the antioxidant capacities of RPs. The results of the current study indicated that the protein digests, in which undigested residues remained, could exhibit more efficacious antioxidant activity compared to the hydrolysates. (C) 2016 Elsevier Ltd. All rights reserved.