Structure-dependent effects of laccase-mediated phenolic acid incorporation into starch nanoparticles on starch...

This study investigated the structure-dependent effects of laccase-mediated incorporation of ferulic acid (FA), caffeic acid (CA), gallic acid (GA), and tannic acid (TA) into starch nanoparticles (SNPs) on the retrogradation of maize starch (MS). Phenolic acid (PA) incorporation increased with increasing structural complexity, with TA-SNPs exhibiting the highest phenolic loading (128.48 mg/g). Spectroscopic and X-ray diffraction analyses supported PA incorporation and revealed disruption of the original A-type crystalline structure of SNPs, limited formation of V-type inclusion-like structures, and reduced relative crystallinity. In MS gels, PA-SNPs inhibited both short- and long-term retrogradation, with inhibitory efficacy positively correlated with the number of phenolic hydroxyl groups. Compared with MS gel, MS/PA-SNP gels exhibited lower retrogradation-associated enzymatic resistance and reduced hardness after 21 days of storage. These findings demonstrate that the PA molecular structure shapes the physicochemical properties of SNPs, thereby modulating their ability to inhibit starch reassociation and recrystallization during storage.