This study aimed to further improve the previously described first-order equation representing in vitro digestion of starch by extensively explaining modified log of slope (LOS) plot method. Hydrolysis curves of various starches were analyzed using original and/or modified LOS plot methods. Some starches showed significant differences in the results from the two methods; specifically, the modified method better described the digestive behavior of starch with various digestion properties, supported by higher determination coefficient values and better estimation of the digestibility data over digestive phase. The digestion parameters obtained from the modified method provided multiple types of information, including amount and digestion rate of each starch fraction (rapidly digestible, slowly digestible, and resistant starch), supporting the concept of digestible fraction classification. Therefore, the modified LOS plot method described here can be applied as an effective tool for analyzing and describing the multi-scale in vitro digestion behavior of starch.
Keywords: First-order kinetics; In vitro Englyst assay; Modified LOS plot equation; Multi-scale digestion; Starch digestibility.
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