Structural Characteristics and In Vitro Digestibility of Malic Acid-Treated Corn Starch with Different pH Conditions

• Published in: Molecules (Basel, Switzerland) Vol. 24; no. 10; p. 1900
• Main Authors: Lee, Chang Joo, Na, Jong Hee, Park, Jun-Young, Chang, Pahn-Shick
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 17.05.2019; MDPI
• Subjects: Acids; Birefringence; Calories; Carbonyl compounds; Carbonyl groups; Carbonyls; Cookies; Corn; corn starch; Crosslinking; Dietary fiber; Digestibility; Esterification; Food; Food processing; Hydrogen bonds; in vitro digestibility; Infrared spectroscopy; Malic acid; modified starch; Processed foods; resistant starch; Spectrum analysis; Starch; Starches; Vegetables; in vitro digestibility; malic acid; modified starch; corn starch; resistant starch
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules24101900

The objective of this study was to investigate the influence of pH value on the in vitro digestibility of malic acid-treated corn starch in relation to its structural properties. Varying pH values (1.5-8.5) of 2 M malic acid solution were combined with corn starch in a forced-air oven at 130 °C for 12 h. Using Fourier-transform infrared spectroscopy (FT-IR), carbonyl groups were detected in malic acid-treated corn starch, indicating cross-linking through esterification. As the pH value of malic acid-treated corn starch decreased from 8.5 to 1.5, the resistant starch content increased from 18.2 to 74.8%. This was the result of an increased degree of substitution and was maintained after gelatinization. The granular structure of malic acid-treated corn starches was not destroyed, and the starches maintained birefringence. This malic acid-treated corn starch could be utilized in heat processed foods such as bread and cookies as well as in products with reduced calories.