米糠蛋白酶法改性前后的功能特性变化研究

Study on functional properties of rice bran protein before and after modification

以蛋白质为配料的产品中,蛋白质功能性质往往比营养价值更重要,直接影响到米糠蛋白的应用前景。实验研究了经碱性蛋白酶改性后的米糠蛋白功能特性,并与其改性前进行了比较。测定了改性前后米糠蛋白的溶解性、乳化性及乳化稳定性、起泡性及泡沫稳定性,并确定浓度、温度等因素对上述指标的影响。实验结果表明,改性后米糠蛋白的溶解性、起泡性及乳化性与改性前相比均有较大改善,分别提高了140.46%、117.38%、100.50%。米糠蛋白溶解性在pH4.0～6.0较低,在碱性条件下较高,随温度升高而增大;米糠蛋白乳化性、起泡性在碱性条件下较高,随温度的升高其起泡能力和乳化能力均增强。

Protein structure determines the functional properties of proteins ,and during the extraction process, many factors effect protein structure, resulting in functional change. Protein ingredients in the product,functional properties of rice bran protein was often more important than nutritional value of protein,directly effects the application prospect. Experiment studied that rice bran protein functional properties modified by alkaline protease,and comparison of rice bran protein without modifying. Determinated of the rice bran protein solubility,emulsification and emulsion stability,foaming and foam stability before and after modification. And protein concentration,temperature and other factors affected these indexes. The result showed that after modification,rice bran protein＇s solubility,foamability and emulsibility had been improved greatly,respectively improved 140.46%, 117.38%, 100.5%. The rice bran protein solubility was lower in pH4.0-6.0. Under the higher alkalinity condition,the protein solubility increased with temperature increasing. The rice bran protein foamability and emulsibility were high under the alkalinity condition and increased with temperature and protein concentration obviously.