Colloid-encapsulated sugarcane polyphenols and their impact on in vitro starch digestibility: enhancing bioaccessibility and α-amylase inhibitory effect

Summary This study focuses on encapsulation of sugarcane polyphenols (SPs) to assess its impact on their bioaccessibility and efficacy in inhibiting starch digestion, thereby contributing to glycaemic control strategies. The hypothesis posits that encapsulation enhances both the bioaccessibility and functional effectiveness of SPs. Carboxymethyl cellulose (CMC) and carrageenan (CAR) were employed as encapsulating agents. The methodology included an evaluation of α-amylase inhibitory activity and the bioaccessibility of SPs across various encapsulation formulations in vitro digestion, highlighting a specific formulation that combines 0.5% CMC and 0.5% CAR to encapsulate 0.4% SPs. Findings reveal that this formulation significantly increases SPs' bioaccessibility and exhibits the highest α-amylase inhibitory activity, suggesting its potential to support a low glycaemic index (GI) diet (GI = 54.7). It was observed that the GI is significantly inversely correlated with the bioaccessibility of total polyphenols and proanthocyanidins in SPs, while the bioaccessibility of total flavonoids in SPs showed no significant effect on pGI. Interestingly, SPs encapsulated with CMC were less effective in inhibiting starch digestibility than unencapsulated SPs, attributed to the tight binding of CMC with polyphenols, which limits their interaction with starch and α-amylase. The study highlights the crucial influence of encapsulation materials on polyphenol functionality and emphasises the need for strategic encapsulation in modulating glycaemic responses. These findings advance the understanding of how processing technologies can optimise the health benefits of dietary bioactives, guiding future research towards functional applications and dietary interventions for glycaemic control.