Porous starch granules loaded curcumin and resveratrol modulate starch digestibility of wheat bread: Toward developing novel functional foods

The demand for functional foods is increasing due to their health benefits beyond basic nutrition. This study evaluates the development of functional bread containing curcumin and resveratrol encapsulated porous starch granules and assesses their effect on physical and chemical properties of bread, starch digestibility, and antioxidant capabilities. Seven bread formulations, including control, non-encapsulated polyphenols (curcumin and resveratrol), and encapsulated polyphenols at various concentrations (0.5 and 1% w/w), were compared. The curcumin-loaded/resveratrol-loaded porous starch added bread formulations showed concentration-dependent reductions in loaves specific volume than white bread (WB) and significantly reduced yellowness from the curcumin bread (CB). However, the springiness and chewiness remained similar across all the bread formulations. Bread with encapsulated polyphenols exhibited a significant increase in total phenolic content, reaching up to 550 mg GAE/100 g. Antioxidant activity was also boosted, with 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity peaking at 91.99% in resveratrol porous starch-encapsulated bread at 01% (RPSB01). Encapsulation reduced the rapidly digestible starch from 64.92% in control bread to 40.58% in RPSB01, with a concomitant increase in resistant starch and slowly digestible starch amounts. The encapsulated polyphenols displayed a controlled and delayed release in simulated gastric digestion, with released amounts of 0.76 mg/g and 0.82 mg/g, respectively, and follows Makoid-Banakar release kinetics suggesting the non-Fickian diffusion mechanism. Overall, encapsulating polyphenols in porous starch granules significantly improves their retention, bioactivity, and potential health benefits, providing a promising approach for making functional bread with enhanced nutritional qualities and the potential to improve health.