Structural enhancement of starch-linoleic acid complexes by resonance acoustic treatment

The effects of resonance acoustic (RA) treatment on the structural of starch-linoleic acid (LOA) complexes were investigated. By using four types of starches (i.e. mung bean, pea, sweet potato, and potato), RA treatment was compared with that of rapid visco analyzer (RVA) treatment. The results demonstrated that RA treatment was markedly superior to RVA in forming more ordered and stable V-type complexes. This was evidenced by a significant increase in complex index (by 16.3%-22.0%) and enthalpy changes (by 48.9%-590.7%), alongside elevated relative crystallinity and peak temperatures. Spectroscopic analyses, including Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and Small-Angle X-ray Scattering, consistently revealed enhanced structural ordering, reflected in higher IR 1047/1022 cm -1 ratios, reduced Raman band widths (FWHM), and increased fractal dimensions (Dm). Confocal laser scanning microscopy visually confirmed the promoted aggregation of complexes into a more organized state. The proposed mechanism involves RA-induced dynamic stretching of starch helices and amplified C-H coupling vibrations, which facilitate the orderly alignment and crystallization of the starch-LOA complexes. These findings demonstrate the potential of RA treatment in improving the thermal stability of starchy foods and increasing their resistant starch content, thus offering significant promise for food industrial applications. • RA increases the enthalpy changes and peak temperature in starch-LOA complexes. • RA enhances the starch-LOA complex index compared to RVA processing. • RA increases the long-range and short-range orderliness of starch-LOA complexes. • RA promotes the aggregation of starch-LOA complexes into an ordered state.