Optimization of the response surface for semi-dry preparation of acetylated chickpea starch and its structural, physicochemical and in vitro digestibility

Acetylation modification can effectively address the inherent shortcomings of native starch in food applications. There have been limited studies on acetylated chickpea starch (ACPS), predominantly using the wet method. However, fewer studies have comprehensively explored the semi-dry method to optimize the modification conditions. This study aimed to optimized the processing conditions for the semi-dry preparation of ACPS esters using a response surface methodology and evaluated starch granule morphology, pasting properties, physicochemical characteristics, and in vitro digestibility. Fourier transform infrared spectroscopy (FTIR) confirmed the successful introduction of acetyl groups to the starch molecule. Scanning electron microscopy (SEM) images revealed slight aggregation on the surface of ACPS particles. ACPS exhibited improved performance in terms of solubility, swelling power, and transparency. Acetylation modified the starch's pasting properties, resulting in ACPS with reduced pasting temperature and higher peak viscosity. ACPS showed a significant decrease in in vitro digestibility and an increase in resistant starch content from 3.24 g/100 g–12.87 g/100 g. This study offers a theoretical reference for the semi-dry preparation of acetylated starch, and the significant improvement in physicochemical properties underscores its potential as a food additive, thereby broadening the application scope of chickpea starch in the food industry.