4-α-糖基转移酶对大米淀粉消化特性的影响

Effect of 4-α-Glucanotransferase Modification on the Digestibility of Rice Starch

DOI：

中文关键词: 4-α-糖基转移酶 大米淀粉 消化特性

英文关键词: 4-α-glucanotransferase rice starch digestibility

基金项目:国家自然科学基金项目(20976070);江苏省科技支撑计划项目(BE2008317);江苏省自然科学基金项目(BK2009069)

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中文摘要:

用4-α-糖基转移酶对大米淀粉进行改性,采用体外模拟消化实验测定了改性后大米淀粉的消化特性,并通过差示扫描量热(DSC)、X-射线衍射(X-ray)、扫描电镜(SEM)对改性后大米淀粉消化特性改变的原因进行了探讨。结果表明,大米淀粉经4-α-糖基转移酶改性后,慢消化淀粉质量分数先增加后减小,并在改性3~4 h达到最大值;DSC测定发现,酶改性2~6 h时样品回生焓增加,而酶改性6 h及以上则淀粉回生焓逐渐降低;X-ray结果显示,改性淀粉晶型逐渐由A型变为B型;SEM结果表明,改性后淀粉变得粗糙不规则,且有很多小颗粒紧密堆叠。这些理化特性的变化可以在机理上对淀粉消化性的变化进行一定的解释。

英文摘要:

This manuscript study the effect of 4-α-GTase on the digestibility of rice starch,then the corresponding mechanisms was elucidated by differential scanning calorimetry(DSC),X-ray diffraction(X-ray),and scanning electron microscope(SEM).It was found that: 1) The content of the slowly digestible starch(SDS) in starch increased to the maximum value when modified for 3～4 h by 4-α-GTase(50 U/g dry starch),and then decreased with increasing of the modification time;2)During of 2～6 h modification,the rate of retrogradation was accelerated,then gradually decreased after 6 h;3) The crystal structure of starch was changed from A-type to B-type after treated by 4-α-GTase;4) The surface of starch became rough and irregular with more and smaller fraction stacked.From the above results,it is can be concluded that the changes of the digestibility could be attributed to the changes of structure and property.

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