慈姑抗性淀粉的理化特性研究

Physico-chemical Properties of Arrowhead Resistant Starch

采用酸解-微波法制备慈姑抗性淀粉(resistantstarch,RS),结果发现慈姑RS形成了新的连续的致密结构,结晶以初级微晶为主,晶型转变为C型,结晶度为23.62%;RS-碘复合物的最大吸收波长为564.40nm;随着RS含量的增加,慈姑RS的直链淀粉含量变化不大,大部分可溶性直链淀粉转变为不溶性直链淀粉,平均聚合度明显降低,提纯RS的平均聚合度为22.94;红外光谱分析表明,慈姑RS含有伯、仲醇羟基和α-D-吡喃环结构特征,只较原淀粉形成了更多的氢键,说明其是物理改性淀粉。慈姑RS的溶解度、透明度大大低于原淀粉,而持水力较原淀粉有明显的提高。

Arrowhead resistant starch （RS） was prepared by acid hydrolysis followed by microwave heating.New continuous compact structure was formed in arrowhead RS.Elementary crystallites were the major components of arrowhead RS crystal.The crystalline pattern of arrowhead RS was changed into C type and the crystallinity was 23.62%.The maximum absorption wavelength of arrowhead RS-iodine complex was 564.40 nm.As more RS was formed,there was a significant decrease in the degree of polymerization （DP） and the DP of purified arrowhead RS was 22.94,and most soluble amylose was converted into insoluble amylase,but less change in amylose content was observed.Infrared spectral analysis showed arrowhead RS contained primary and secondary alcoholic hydroxyl groups and the structure of α-D-pyran ring.Structurally,arrowhead RS presented only more formed hydrogen bonds when compared with its native counterpart.Therefore,the modification for arrowhead starch is physical modification.Moreover,arrowhead RS also exhibited lower solubility and transparency but higher water-holding capacity in comparison with its native counterpart.