为了研究大米清蛋白、球蛋白、醇溶蛋白和谷蛋白体外消化产物的抗氧化活性，用Osborne法从大米粉中提取大米四种蛋白。采用胃-胰蛋白酶分步酶解，选择DPPH?，ABTS+?，?OH自由基清除能力和Fe2+金属离子螯合能力四个指标对消化产物的抗氧化活性进行综合评价。与市售的大豆肽比较，大米四种蛋白经模拟体外消化后具有良好的抗氧化活性。其中醇溶蛋白的消化产物抗氧化活性最好，DPPH?，ABTS+?，?OH自由基清除能力和Fe2+金属离子螯合能力的半抑制浓度分别为30.88 mg/mL、27.61 mg/mL、5.43 mg/mL、0.18 mg/mL。大米四种蛋白酶解产物的Fe2+螯合能力半抑制浓度均小于1 mg/mL，具有良好的Fe2+螯合能力。研究结果表明大米四种蛋白的体外消化酶解物具有不同大小的抗氧化活性，分子量集中在181~1000 Da范围内，是一种易于被人体吸收的抗氧化肽。

The Osborne method comprising of a 2-step in vitro digestion of rice flour was used to extract albumin, globulin, prolamin, and glutelin by using pepsin and trypsin. Subsequently, the antioxidant activity of the resultant rice digest was studied in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH?), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+?) and ?OH radical scavenging as well as Fe2+-chelating activity. The results revealed that the in vitro digests of four rice proteins exhibited better antioxidant activity than commercial soybean peptides. Among these, the digest of prolamin showed the highest antioxidant activity, where the half-maximal inhibitory concentration (IC50) values of DPPH?, ABTS+?, and ?OH radical-scavenging as well as Fe2+-chelating activities were 30.88, 27.61, 5.43, and 0.18 mg/mL, respectively. The enzymatic hydrolysates of albumin, globulin, prolamin, and glutelin showed good Fe2+-chelating activities with IC50 values < 1 mg/mL. The results indicated that the in vitro digests of the four rice proteins tested in this study showed different antioxidant activities and that the molecular weights of these small peptides were in a range of 181~1000 Da, which is similar to that od antioxidant peptides that can be absorbed easily in humans.

国家自然科学基金（31401505）；公益性行业（农业）科研专项经费资助（201303070）