黑米蛋白的功能与结构性质

Analysis of functional and structural properties of black rice protein isolates

以黑米为原料,通过碱提酸沉法提取黑米蛋白,并与大豆分离蛋白进行对比,研究该蛋白的功能与结构性质。研究结果表明,黑米蛋白与大豆分离蛋白的功能性质具有显著的差异,具体表现为:黑米蛋白的乳化稳定性与持油性高于大豆分离蛋白,而黑米蛋白的溶解性、乳化性、起泡性、起泡稳定性与持水性均低于大豆分离蛋白。此外,黑米蛋白的变性温度为87.35℃。采用红外光谱法对黑米蛋白特征官能团进行测定,得出羰基、氨基及羧基等特征官能团。二级结构测定结果表明黑米蛋白中α-螺旋含量为5.15%,β-折叠含量为40.65%,β-转角含量为21.70%,无规则卷曲含量为32.40%。

The components of main black rice protein isolates were extracted from black rice powder by alkali-soluble acid-precipitation method,and compared with soybean protein isolates to study their functional and structural properties. The results showed that the functional properties of black rice protein isolates and soy protein isolates were significantly different,as the emulsion stability and oil holding capacity of black rice protein isolates were higher than that of soy protein isolates. In comparison,the solubility,emulsibility,emulsion stability,foamability,foaming stability,and water holding capacity of black rice protein isolates were lower. In addition,the denaturation temperature of black rice protein isolates was 87.35 ℃. The characteristic functional groups of black rice protein isolates were determined by infrared spectroscopy,and the functional groups such as carbonyl,amino and carboxyl groups were detected. The secondary structure of black rice protein isolates consisted of 5.15%α-helix,40.65%β-sheet,21.70%β-turn,and 32.40% random coil.