关键词: 玉米淀粉, 直链淀粉, 热力学性质, 消化性

Abstract:

Four kinds of corn starches with different amylose /amylopectin contents,namely,waxy corn starch,normal corn starch,Hylon Vand Hylon VII,were investigated in the aspects of thermodynamic property and in vitro digestibility,and the relationship between the two properties was further analyzed. It is found that the thermodynamic property difference between the native high-amylopectin ( waxy and normal) corn starches and the high-amylose
( Hylon Vand Hylon VII) ones is great,that the pasting temperatures of the high-amylopectin corn starches are about 70℃,while the high-amylose corn starch ( Hylon VII) is resistant to gelatinization even in the boiling water,that the peak viscosities of four kinds of corn starches varieties significantly decrease with the increase of amylose content,that the normal corn starch with proper amylose content is of high swelling power,and that the swelling powers of normal corn starch,Hylon V and Hylon VII at 90℃ are respectively 13. 07,5. 63 and 4. 54 g /g. DSC analysis reveals that the waxy corn starch is of one single endothermic peak,while both the normal corn starch and the high amylose starch are not only of an additional endothermic peak of amylose-lipid complex but also of a lower total enthalpy change,and that,after the treatment with the boiling water,the normal corn starch with lower pasting temperature and higher swelling power is of higher slowly-digestible starch content,while the high-amylose corn starches with higher pasting temperature and lower swelling power are of higher resistant starch content.

Key words: corn starch, amylose, thermodynamic property, digestibility