Effects of Phenolic Acids with Different Structures and Lauric Acid on the Digestive Properties and Physicochemical Characteristics of Breadfruit Starch

This study examined how complexes formed between breadfruit starch, lauric acid (LA), and phenolic acids (gallic/GA, 3,4-dihydroxyphenylacetic/DOPAC, caffeic/CA) affect starch digestibility and properties. All complexes increased resistant starch (RS) content from 47.19% (native) to 49.12–70.14%, with the caffeic acid-starch binary complex showing the highest RS (70.14%) and lowest hydrolysis index (52.60). LA-containing samples formed V-type inclusion complexes, evidenced by a cooling-phase viscosity peak, while polyphenol-only samples did not. The formation of the complex raised the starch gelatinization peak temperature from 78.6 °C to 100.6–120.9 °C. Structural analysis indicated increased short-range order and crystallinity. Ternary complexes exhibited lower short-range order but higher crystallinity than binary complexes, suggesting LA primarily influences long-range order, while polyphenols affect both short- and long-range structure. These findings clarify interaction mechanisms in starch–lipid–polyphenol systems for designing low-digestibility foods.