Comparative study of annealed and heat-moisture treated starch: Structural properties and prebiotic functionality after Lactobacillus plantarum fermentation

Abstract

This study investigated the structural changes and prebiotic potential in hydrothermal modified starches from Chinese yam (Jiaozuo, China), namely annealed (ANN) and heat-moisture treated (HMT) starch, during fermentation by Lactobacillus plantarum. The results demonstrated that the degradation pathway of starch is fundamentally dictated by its pretreatment-induced structure. Native starch (NS) resisted microbial action due to its compact architecture, while ANN starch underwent selective degradation due to the swelling of plasticized amorphous regions. In contrast, HMT starch exhibited a distinctive slow-release profile, characterized by the enzymatic cleavage of long-chain amylopectin and a gradual decline in relative crystallinity, which facilitated a sustained release of carbon sources. In vitro fecal fermentation results revealed that HMT starch fermented for 32 h with Lactobacillus plantarum (HMT32) most effectively regulated gut microbiota composition by promoting the growth of beneficial genera such as Ligilactobacillus and Limosilactobacillus, while inhibiting opportunistic pathogens including Enterococcus and Escherichia-Shigella. The HMT32 group specifically enriched microbial biomarkers associated with Lactobacilli. These findings demonstrate that the combination of physical modification and microbial fermentation synergistically improves the prebiotic functionality of starch, positioning HMT starch as a promising targeted prebiotic material for improving gut health.

Keywords: Gut microbiota; Lactobacillus plantarum; Physical modification; Structural change.