Physicochemical and physiological characteristics of resistant starch type 5 derived from rice starch beta-limit dextrin

Abstract

In this study, resistant starch (RS) type 5 was prepared via complexation of beta-limit dextrin (BLD) from rice starch and lauric acid (LA), and its physicochemical and physiological properties were characterized. The production of BLD was confirmed by reductions in molecular weight and the α-1,4/α-1,6 linkage ratio (41.32 to 6.42) compared to native starch. The BLD exhibited great complex-forming ability with LA, as indicated by high complex melting enthalpy and a pronounced V-type crystalline structure. The RS content of the BLD complex with LA (BLD × LA) determined by in vitro assay was 27.5 %. Consumption of BLD × LA in a mouse model resulted in a tendency toward a lower blood glucose response after ingestion. After five weeks of dietary supplementation, the BLD × LA group showed no significant changes in an oral glucose tolerance test or insulin resistance but exhibited a positive effect in the food efficiency ratio. Additionally, hepatic fat accumulation was suppressed in mice fed the BLD × LA diet, likely through regulation of hepatic lipogenesis and cholesterol homeostasis. Overall, this study demonstrated the excellent lipid inclusion complex-forming ability of BLD and suggested its potential as a source of RS type 5 based on the verified effects in both in vitro and in vivo models.

Keywords: Beta-limit dextrin; In vivo efficacy; Resistant starch type 5; Starch digestibility; Starch-lipid complex.