大米淀粉-单甘酯复合物的性质和结构研究

Study on the Properties and Structure of Rice Starch-Monoglyceride Complexs

为了减缓大米淀粉在食品加工过程中的老化,采用加热糊化法制备大米淀粉-不同单甘酯复合物,研究甘油单月桂酸酯(GML)、甘油单棕榈酸酯(GMP)和甘油单硬脂酸酯(GMS)三种单甘酯对复合物的理化和结构特性的影响。采用RVA、DSC、FTIR、XRD等方法测定了复合物的糊化特性、热特性、短程有序性及结晶结构。结果表明,不同单甘酯对复合物的复合指数具有显著影响(P<0.05),复合指数为GMP>GMS>GML;与原大米淀粉相比,复合物的溶解度、析水率、回生值以及短程有序性均显著下降(P<0.05),且不同复合物之间也存在显著差异(P<0.05),其中大米淀粉-甘油单棕榈酸酯的析水率、回生值和短程有序性最低,分别为25.58%、281.7 cP和0.58;差式扫描量热和X-射线衍射分析发现,与单甘酯复合后,淀粉由A型结晶结构转变为V型结晶结构。上述结果表明单甘酯的加入在一定程度上可延缓淀粉老化,大米淀粉-甘油单棕榈酸酯复合物抑制淀粉老化效果更好。

To slow down the aging of rice starch during food processing,rice starch-monoglyceride complexes were prepared by heating pasting method,and the effects of three monoglycerides,glycerol monolaurate(GML),glycerol monopalmitate(GMP)and glycerol monostearate(GMS),on the physicochemical and structural properties of the complexes were investigated.The pasting properties,thermal properties,short-range ordering and crystalline structure of the complexes were determined by RVA,DSC,FTIR and XRD.The results showed that different monoglycerides had significant effects on the complex index(P<0.05),and the complex index was GMP>GMS>GML.The solubility,precipitation rate,regeneration value and short-range orderliness of the complexes were significantly lower compared with the original rice starch(P<0.05),and there were also significant differences between the complexes(P<0.05).Among them,rice starch-glycerol monopalmitate had the lowest precipitation rate,regeneration value and short-range orderliness of 25.58%,281.7 cP and 0.58,respectively.Differential scanning calorimetry and X-ray diffraction analysis revealed that the starch changed from A-type crystalline structure to V-type crystalline structure after compounding with monoglycerides.The above results indicated that the addition of monoglycerides could retard starch aging to some extent,and the rice starch-glycerol monopalmitate complexes were more effective in inhibiting starch aging.