Characterization of grape seed polyphenol-loaded Rice bran oil emulsion and its effects on the quality and digestibility of Rice cake.

This study developed a rice bran oil emulsion containing grape seed proanthocyanidins (GSP), which was stabilized by gliadin and pectin, so as to enhance the quality and nutritional functionality of traditional rice cake. The emulsion was characterized by CLSM, FTIR, TEM, and rheological analysis. The stabilization mechanism was elucidated through multi-scale characterization. CLSM confirmed a dense interfacial particle layer around oil droplets. FTIR revealed non-covalent interactions among GSP, gliadin, and pectin.Upon incorporation into rice cake, it significantly improved sensory quality,and XRD identified V-type inclusion complexes between GSP and starch at 2θ ≈ 20°. In vitro digestion showed that the emulsion reduced rapidly digestible starch from 70.35% to 55.03% and increased resistant starch from 4.22% to 14.39%, with the predicted glycemic index declining from 94.61 to 84.73. These findings demonstrate that the emulsion system can impart anti-staling and slow-digesting properties to starch-based foods and that it offers a novel strategy for functional staple development.