# New Insight into the Multi-Scale Structure and Anti-Digestibility of Nano-Scale Amylopectin Ternary Assemblies Prepared Under High-Power Ultrasound

## TL;DR

This study explores how high-power ultrasound affects the structure and digestibility of nano-scale amylopectin assemblies, leading to higher resistant starch content and lower glycemic index.

## Contribution

The study reveals how ultrasound power influences the multi-scale structure and anti-digestibility of nano-scale amylopectin ternary assemblies.

## Key findings

- Higher ultrasound power increases RS-V content (22.66–60.17%) and reduces glycemic index.
- Ultrasound promotes compact molecular networks and reduces hydrolysis sites in amylopectin assemblies.
- EFA–lauric acid–lactoglobulin assemblies under 600 W ultrasound show superior anti-digestibility compared to traditional starches.

## Abstract

High-power ultrasound has been widely used to regulate the anti-digestibility of starch-based products, including the formation of resistant starch (RS-V) in amylopectin assemblies. This can contribute to the attenuation of postprandial hyperglycemia. However, the mechanisms by which high-power ultrasound modulates RS-V remain to be elucidated. Therefore, nano-scale Euryale ferox amylopectin (EFA) ternary assemblies were constructed under high-power ultrasound. All EFA assemblies exhibited ternary self-assembly peaks and V-type crystallinity. Combined chemometric analyses revealed that, with increasing ultrasound power, the rising self-assembly sites within B2 and C chains promoted the increase in self-assembly index but decreased semicrystalline lamellae thickness and structural fractal dimension. Consequently, a compact and ordered molecular cross-linking network was formed, contributing to increases in residual crystallinity, molecular weight, short-range order, and molecular density. This resulted in the shrinkage of digestion channel structures and optimization of the molecular gel network. As a result, the reduction in hydrolysis sites with increasing ultrasound power led to increased RS-V content (22.66–60.17%), causing a decline in the estimated glycemic index. The EFA–lauric acid–lactoglobulin assemblies prepared under 600 W ultrasound were the optimal composition and exhibited enhanced anti-digestibility relative to amylopectin assemblies derived from staple crops such as white waxy maize. The present investigation not only serves as a valuable supplement for studying the precise regulation mechanisms of nano-scale amylopectin RS-V, but also provides critical theoretical guidance for the development of foods aimed at preventing hyperglycemia.