Starch is classified as fast digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) depending on digestibility. RS can avoid enzymatic digestion in the small intestine, but microbes in the large intestine can ferment some RSs. The purpose of this study was to investigate the structural characteristics of low digestible starch by malic acid mutation in rice, corn and potato starch. Rice, corn and potato starch were treated with a 2M malic acid solution in a forced air oven at 130 ° C for 12 hr. Using FT-IR, carbonyl groups were detected in malate starch, indicating the formation of cross-linking by esterification. And, Using X-ray, diffractograms of malic acid-treated starch. In the micrographs, malate treated corn and potato starch granules were marked with elliptical or polygonal shapes and starch retained birefringence. Through microscopic observe in morphology of starch granules, Microscopic observation did not reveal any changes in morphology of starch granules. The modified starches had higher RS than the control and native starch. RS content of maltitized rice, corn and potato starch was 87.6%, 89.8% and 64.8%, respectively. Malic acid treated RS was maintained after the cooking process. The RS of substituted starches increased with increasing degree of substitution. These results suggest that the increase in RS content by malic acid treatment is caused by the change in the structure. And the highest resistant starch content (86.7%) was found at pH 1.5, 2M of malic acid treated corn starch. Malic acid-treated starch can be used as heat-stable and low-digestible starch containing food ingredients.

• Kyeong A Jeong(Department of Food Science and Biotechnology, Wonkwang University)
• Chang Joo Lee(Department of Food Science and Biotechnology, Wonkwang University)