Physicochemical Properties and In Vitro and In Vivo Digestive Properties of Pea Starch Complexes Incorporated Different Polyphenols

Abstract

The prevalence of Type 2 diabetes mellitus (T2DM) has become a major public health concern worldwide. Slowly digested or indigestible carbohydrates, such as starch complexes, are associated with a low glycemic index (GI) and a reduced risk of developing T2DM. In this study, pea starch–polyphenol complexes were prepared by incorporating three types of polyphenols with varying polarities: anthocyanin, gallic acid, and quercetin. The physicochemical and digestive properties of these three different pea starch–polyphenol complexes were investigated. The results showed that all three polyphenols could bind with pea starch to form complexes and increase the content of resistant starch. Among them, quercetin resulted in the highest resistant starch content (17.62%), surpassing the other two polyphenols. X-ray diffraction (XRD) analysis indicated that all pea starch–polyphenol complexes exhibited a V-type crystalline structure. The crystallinity of the quercetin–pea starch complex was 5.7%, suggesting a greater formation of amylose–quercetin single helices compared to the other two starch–polyphenol complexes. In vitro digestion results demonstrated that the quercetin–pea starch complex had the highest indigestibility among the three, with α-amylase inhibition ratios of 52.40%, 50.13%, and 49.23% for the quercetin–pea starch, anthocyanin–pea starch, and gallic acid–pea starch complexes, respectively. Consistent with the in vitro findings, in vivo experiments showed that zebrafish fed with the quercetin–pea starch complex exhibited the lowest postprandial glycemic response. Additionally, the intake of the quercetin–pea starch complex led to a lower abundance of harmful gut bacteria, including Proteobacteria and Firmicutes compared to the anthocyanin–pea starch and gallic acid–pea starch complexes. These findings suggest that polyphenols can delay the metabolism of pea starch by inhibiting α-amylase activity and modulating gut microbiota composition. Furthermore, this study highlights that hydrophobic polyphenols exert a more significant impact on the digestibility of pea starch. In summary, quercetin–pea starch complex has great potential in regulating postprandial blood glucose in vitro and in vivo.