Molecular characteristics and digestion properties of corn starch esterified by l ‐malic acid

Abstract

Malate starch was prepared by dry heat treatment of corn starch with l-malic acid. Malate starch has lower swelling degree and gelatinization property than the original starch. The polarization cross gradually disappears, and the particle size becomes larger. However, as the degree of substitution increased, the polarization cross became weak and eventually disappeared due to the destruction of the crystal structure. The results of infrared spectroscopy indicated that malate starch showed a characteristic peak of carbonyl vibration at 1,739 cm−1, and the peak value of the substitution increased significantly. The weak peak in the 165–180 region of the nuclear magnetic carbon spectrum is the chemical shift of the ester carbonyl carbon formed by esterification. The 13C NMR results speculated that the hydroxyl group of l-malic acid C9 and starch C6 was esterified to form malate starch. The digestion experiments showed that the content of resistant starch after esterification increased significantly. Practical applications Esterified starch is an important part of modified starch. After organic acid treatment, starch can be more widely used in various industries according to its different properties. In this study, the low degree of substitution malate starches were constructed by combining the chemical bonds of corn starch and l-malic acid, and the effects on physical and chemical properties, molecular characteristics, and digestion characteristics were studied to improve the processing characteristics of starch and improve the product addition value.