谷氨酰胺酶催化交联大米蛋白对大米淀粉理化特性的影响

Effects on Physicochemical Properties of Rice Starch by Cross-linking Rice Protein Catalyzed by Glutaminase Enzyme

为弄清谷氨酰胺酶(TG)催化交联前、后大米蛋白对大米淀粉理化特性的影响,测定淀粉的膨胀系数与溶解度、直链淀粉溢出率。采用红外光谱法、可见分光光度法、差示扫描量热仪(DSC)、快速粘度分析仪(RVA)等技术手段分析淀粉共混体系的结构特征和功能特性。结果表明,蛋白在TG酶催化下对淀粉的结构、消化率与其它功能特性均有显著影响,且大米蛋白与淀粉二者间相互作用增强,表现为:大米淀粉的膨胀系数由13.24 g/g降至最低,为7.02 g/g,其直链淀粉溢出量降低38.7%。在TG酶作用下,随着蛋白含量的增加,淀粉短程有序结构的稳定性逐渐增强。添加量为10%的蛋白在TG酶的催化下对淀粉消化性减轻效果更好。TG酶作用前、后蛋白对淀粉的热特性影响不大,而其糊化特性参数均明显下降,黏度也显著降低。TG酶催化蛋白使得淀粉颗粒网络结构更加致密且聚集。结论:TG酶催化交联蛋白对淀粉的改性效果显著。

The purpose of this experiment was to study the effect of rice protein on the physicochemical properties of rice starch before and after glutaminase(TG)catalyzed cross-linking.The functional properties and structural characteristics of starch blending systems were analyzed by technical means such as RVA,and the formation of starch-protein composite systems could be promoted under hydrothermal conditions.The results showed that the protein had a significant effect on the structure,digestibility and other functional properties of starch under the catalysis of TG enzyme,and the interaction force between rice protein and starch under the catalysis of TG enzyme was further enhanced.The expansion coefficient decreased from 13.24 g/g to a minimum of 7.02 g/g,and its amylose overflow decreased by 38.7%;with the participation of TG enzyme,the stability of the short-range ordered structure of starch was gradually enhanced with the increase of protein content.The protein with the addition amount of 10% has a better effect on reducing the digestibility of starch under the catalysis of TG enzyme;before and after the action of TG enzyme,the protein has little effect on the thermal properties of starch,but its gelatinization characteristics parameters were significantly reduced,and the viscosity also significantly decreased;TG enzyme catalyzed protein to make starch granule network structure more dense and aggregated.The above results indicated that the modification effect of TG enzyme catalyzed cross-linked protein on starch was more significant.