脱乙酰魔芋葡甘露聚糖对谷氨酰胺转氨酶凝固大豆分离蛋白凝胶品质特性的影响

Effect of deacetylated konjac glucomannan on quality characteristics oftransglutaminase cross-linking soybean protein isolate gels

为探究脱乙酰魔芋葡甘露聚糖(deacetylated konjac glucomannan, DKGM)对谷氨酰胺转氨酶(transglutaminase, TG酶)凝固大豆分离蛋白(soybean protein isolate, SPI)凝胶品质的影响,制备不同脱乙酰度(DK-1=21.30%,DK-2=36.28%,DK-3=62.85%,DK-4=87.88%)的魔芋葡甘露聚糖,并研究魔芋葡甘露聚糖(konjac glucomannan, KGM)和不同脱乙酰度DKGM对TG酶凝固大豆分离蛋白凝胶及手磨豆干品质影响。相比于空白组,KGM和DKGM提高了大豆分离蛋白凝胶的质构特性。酶交联反应8 h时,凝胶强度从92.03 g增至130.06 g,增强了复合凝胶的白度和持水性,同时蒸煮损失率从8.09%降到2.55%。相比于KGM,DKGM组复合凝胶及烘烤、灭菌后的手磨豆干的硬度、咀嚼性和黏着性均显著性增强。添加DKGM的复合凝胶热变性温度从41.35℃升至44.67℃。DK-3对手磨豆干盐分含量影响较大,所形成的复合凝胶表观形态较佳。扫描电镜观察到S-DK3组凝胶蛋白质复合物网络结构紧凑致密。综上,DKGM能改善大豆分离蛋白凝胶品质特性,适度脱乙酰度的DK-3效果更佳。因此,将KGM进行适度的脱乙酰改性有利于KGM在手磨豆干加工中的应用。

To investigate the effect of deacetylated konjac glucomannan(DKGM)on the quality of transglutaminase(TGase)cross-linking soybean isolate protein(SPI)gels,different deacetylation konjac glucomannan(DK-1=21.30%,DK-2=36.28%,DK-3=62.85%,DK-4=87.88%)were prepared,and the effects of KGM and DKGM on the quality of TGase cross-linking soybean protein isolate gels and dried tofu were investigated.Compared with the blank group,KGM and DKGM improved the textural properties of composite gels of soybean protein isolate,increased the gel strength from 92.03 g to a maximum of 130.06 g at 8 h of enzyme cross-linking reaction time,enhanced the whiteness and water-holding properties of composite gels,and reduced the cooking loss rate from 8.09%to 2.55%.Compared with KGM,the DKGM treatment resulted in relatively high hardness,chewiness,and adhesiveness in composite gel and dried tofu after baking and sterilization.The thermal denaturation temperature of composite gels with DKGM was increased from 41.35℃to 44.67℃,while DK-3 had a better effect on the salt content of dried tofu and a more apparent morphology of composite gel.The SEM results showed that S-DK3 composite gel exhibited a more compact and denser complex network structure.Overall,DKGM improved the quality of soybean protein isolate composite gels,and DK-3 was more effective.Therefore,the KGM with moderate deacetylation modification is favorable for the application in the process of dried tofu.