聚葡萄糖对冻藏面筋蛋白水合及结构的影响

Effect of polydextrose on hydration and structure of gluten during frozen storage

为提高面筋蛋白的冻藏稳定性,采用核磁共振仪、傅里叶红外光谱仪、差示扫描量热仪、动态流变仪和扫描电子显微镜,研究冻藏条件下添加聚葡萄糖对面筋蛋白体系中水分分布、二级结构、热力学特性、流变学特性及微观结构的影响。结果表明,随冻藏时间延长,添加6%(质量分数)聚葡萄糖的面筋蛋白中弱结合水向自由水的转化量显著减少,抑制了面筋蛋白二级结构中α-螺旋下降及无规则卷曲增大,提高了面筋蛋白的热力学稳定性;冻藏7周时,添加6%(质量分数)聚葡萄糖的面筋蛋白,储能模量和耗能模量下降显著小于对照,且面筋蛋白三维网络结构较均匀,孔径较小,连续性较好。结果表明,聚葡萄糖能有效减弱冻藏对面筋网络的破坏,提升面筋蛋白的冻藏稳定性。

In order to improve the stability of gluten during frozen storage,the effects of polyglucose addition on water distribution,secondary structure,thermodynamic properties,rheological properties and microstructure of gluten system were studied by nuclear magnetic resonance(NMR),Fourier transform infrared spectroscopy(FTIR),differential scanning calorimeter(DSC),dynamic rheometer(DHR)and scanning electron microscope(SEM).The results showed that polydextrose(PD)had antifreeze activity.The conversion of immobilized water to free water decreased significantly in gluten by adding 6% PD with increasing of frozen storage time.PD addition inhibited the decrease of α-helix and the increase of random coil in gluten during frozen storage.The addition of PD significantly increased theα-helix content and improved the thermodynamic stability of gluten.With the extension of frozen storage time,the decrease of G′and G″of gluten addition with PD was lower than the control group.The SEM images showed that the gluten network structure with PD addition was more uniform,smaller in pore size and better in continuity after seven weeks of frozen storage.In general,PD could effectively weaken the destruction of gluten network by frozen storage,and thus improve the frozen storage stability of gluten.