Rice protein has attracted considerable attention recently due to its physiological effects. This study extracted the proteins from paddy rice (PR) and germinated paddy rice (GPR) using three methods i.e., alkaline, sodium dodecyl sulfate (SDS) reagent and enzymatic extractions. The extracted proteins or protein fractions were assessed for their properties using various techniques. Data were analyzed by 2′3 factorial design experiment. It was found that germination and extraction methods significantly affected the concentration of protein fractions when analyzed by Bradford assay. Average protein fraction concentration of the GPR was lower than that of PR. SDS-PAGE patterns of protein fractions obtained from PR and GPR using any extraction method displayed similar protein profiles. Three major protein bands at about 13 kDa (prolamin), 22–23 kDa (basic glutelin) and 37–39 kDa (acidic glutelin) with small amount of 57 kDa proglutelin were observed. For amino acid profile, germination increased the content of most amino acids, resulting in the higher content of amino acids in GPR, excepted for some amino acids. When processed with in vitro digestion, protein fractions from GPR exhibited a higher level of digestibility than those from PR as evidenced by the less intensity of the protein bands obtained from SDS-PAGE. Alkaline and SDS reagent extractions provided more digestible protein fractions than enzymatic extraction. Extraction methods also influenced phase transition of protein fractions as investigated by a DSC. Alkaline extraction resulted in protein fractions with higher phase transition temperature than the other methods. For antioxidant capacity, extraction methods as well as germination significantly affected antioxidant capacity of the protein fractions. Enzymatic extraction provided protein fractions with the best antioxidant capacity.

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提取方法对水稻和发芽水稻蛋白质特性的影响

稻米蛋白由于其生理作用最近引起了相当大的关注。本研究使用碱性，十二烷基硫酸钠（SDS）试剂和酶法提取三种方法从水稻（PR）和发芽水稻（GPR）中提取蛋白质。使用各种技术评估提取的蛋白质或蛋白质级分的性质。通过2'3析因设计实验分析数据。发现通过Bradford分析法分析时，发芽和提取方法显着影响蛋白质级分的浓度。GPR的平均蛋白质分数浓度低于PR。使用任何提取方法从PR和GPR获得的蛋白质级分的SDS-PAGE模式显示相似的蛋白质谱。大约13 kDa的三个主要蛋白带（谷醇溶蛋白）观察到22-23 kDa（碱性谷蛋白）和37-39 kDa（酸性谷蛋白）以及少量的57 kDa前谷蛋白。对于氨基酸谱，发芽增加了大多数氨基酸的含量，导致GPR中除某些氨基酸外的氨基酸含量更高。当进行体外消化处理时，GPR的蛋白质级分显示出比PR更高的消化率，这是由SDS-PAGE获得的蛋白质条带强度较小所证明的。与酶提取相比，碱性和SDS试剂提取提供了更多的可消化蛋白质级分。提取方法还影响了蛋白质级分的相变，如DSC所研究的。碱萃取得到的蛋白质馏分的相变温度高于其他方法。为了抗氧化能力，提取方法以及发芽会显着影响蛋白质级分的抗氧化能力。酶促提取为蛋白质馏分提供了最佳的抗氧化能力。