Sustainable engineering of mango seed starch biopolymers for food industry applications using acid hydrolysis

Abstract

Starches derived from plant sources offer a wide range of functionalities for various industrial applications; however, their native forms often exhibit limitations that hinder broader use. This study explores the structural, thermal, and spectroscopic transformations of native mango starch (NMS) following acid modification using 0.1 M (MS₀.₁) and 0.3 M (MS₀.₃) hydrochloric acid. Scanning electron microscopy revealed progressive granule disintegration and increased porosity with acid concentration. Thermogravimetric analysis (TGA/DTG) revealed a shift in degradation onset from 145 °C (NMS) to 382 °C (MS₀.₃), with a corresponding increase in thermal residue (27% to 52%). Kinetic modeling via the Coats–Redfern method showed a reduction in activation energy (Ea = 39.60 kJ/mol for MS₀.₃), indicating enhanced degradability. FTIR analysis demonstrated red-shifted O–H stretching, loss of glycosidic C–O–C signals, and emergence of carbonyl bands. These spectral changes correlated with thermal behavior, as confirmed by second derivative analysis. HCl-modification also enhances the functional attributes of mango starch including solubility, swelling power, oil absorption, and freeze-thaw solubility, while moderately increasing gelatinization temperature. Conversely, water absorption capacity decreases, indicating reduced hydrophilicity. Collectively, the results demonstrate that acid hydrolysis is an effective strategy to modulate mango starch properties for improved stability and industrial functionality.