回生抗性淀粉种类对米淀粉凝胶形成的影响

Effect of retrograded resistant starch types on forming rice starch gel

为寻找改善普通米淀粉制品的结构及品质的新型食品添加剂,该文以普通米淀粉为原料,采用快速黏度分析仪、扫描电子显微镜、质构分析仪、全自动X射线衍射仪及示差扫描量热仪等手段,研究添加锥栗、马铃薯与绿豆回生抗性淀粉(retrograded resistant starch,RSⅢ)对米淀粉凝胶微观结构及理化性质的影响。结果表明:添加锥栗、马铃薯及绿豆RSⅢ对米淀粉凝胶的结构及性质产生显著影响(P<0.01),以锥栗RSⅢ的作用最为突出。添加锥栗、马铃薯与绿豆RSⅢ对米淀粉糊的黏度特性没有影响(P>0.05)。未添加RSⅢ的米淀粉凝胶存在很多不规则、深浅不一的大洞,而加入RSⅢ使米淀粉凝胶的网状结构变得更为规整、致密,且其胶着性与黏聚性变化不大(P>0.05);添加锥栗、马铃薯与绿豆RSⅢ后能加速米淀粉凝胶的形成,与未添加RSⅢ的米淀粉凝胶比,其硬度分别增加了2.38、1.97和1.25倍(P<0.01),黏着性分别增加2.56、1.99和1.32倍(P<0.01),弹性增加1.07、0.81和0.53倍(P<0.01)。米淀粉以A-型晶体占优,锥栗RSⅢ以V-型晶体占优,马铃薯与绿豆RSⅢ均以B-型晶体占优;不加或加入RSⅢ的米淀粉凝胶粉末都转变为以V-型晶体为主,且总相对结晶度没有改变(P>0.05)。加入RSⅢ后的米淀粉糊除有低温吸热峰外还出现高温吸热峰,是否添加RSⅢ对低温吸热峰的温度参数影响不大(P>0.05),但吸热焓显著降低(P<0.01);而对于高温吸热峰,添加马铃薯与绿豆RSⅢ的各项参数没有差别(P>0.05),但比添加锥栗RSⅢ的显著增高(P<0.01)。可见添加不同来源的RSⅢ可以有效改善米淀粉凝胶的结构与品质。该研究结果为抗性淀粉用于提高米制品品质与营养功能的研究和生产提供了重要参考。

In order to improve the structure and qualities of general rice starch products, effects of retrograded resistant starches（RSⅢ） made from Castanea henryi（C. henryi）, potato and mung bean on microstructure and physicochemical properties of rice starch gels were investigated by using modern analysis methods, including RVA-4 rapid viscosity analyzer, S-3400 N scanning electron microscope, TA-XT Plus structure analyzer, D/max2500 automatic X-ray diffractometer and DSC200 differential scanning calorimeter. The results demonstrated that the structure and properties of rice starch gel had a significant change（P〈0.01）after adding C. henryi, potato and mung bean RSⅢ, respectively. Especially the role of C. henryi RSⅢ was the most prominent. The C. henryi, potato and mung bean RSⅢ had no effect（P〈0.05） on viscosity properties of rice starch pastes. Rice starch gel without RSⅢ had a lot of irregular, deep and shallow large holes, while the net structure of rice starch gel with RSⅢ became more uniform and dense. RSⅢ had little influence on gumminess and cohesiveness of rice starch gel（P〈0.05）. The C. henryi, potato and mung bean RSⅢ could accelerate the formation of rice starch gel. Compared with the rice starch gel without RSⅢ, their hardness increased by 2.38, 1.97 and 1.25 times（P〈0.01）, stickness increased by 2.56, 1.99 and 1.32 times（P〈0.01）, and spring increased by 1.07, 0.81 and 0.53 times（P〈0.01）, respectively. A-type crystal was dominant in rice starch, and V-type crystal was dominant in C. henryi RSⅢ, while B-type crystal was dominant in potato and mung bean RSⅢ. Whether or not adding RSⅢ, V-type crystal in rice starch gel powders was transformed as the main crystal shape, and their total relative crystallinities had not changed（P〈0.05）. In addition to a low temperature endothermic peak, rice starch pastes with RSⅢ showed a high temperature endothermic peak. Whether or not to add RSⅢ, the change of temperature parameters of low temperature endothermic peak was a little（P〈0.05）, but its endothermic enthalpy decreased significantly（P〈0.01）. As for the high temperature endothermic peak, all parameters of rice starch pastes with potato and mung bean RSⅢ had no difference（P〉0.05）, but they were significantly higher than those of rice starch paste with C. henryi RSⅢ（P〈0.01）. To sum up, adding RSⅢ with different sources can effectively improve the structure and quality of rice starch gel. The present results can provide an important reference for using the RS to improve the qualities and nutritional functions of the rice products.