Characterization, in vitro digestion properties and antioxidant activity of tropical starch - gallic acid complex

This study investigated the complexes of gallic acid (GA) with cassava starch (CS), breadfruit starch (BFS), and banana starch (BS)-to evaluate their physicochemical properties, digestion behaviors, and antioxidant activities. The complexation rates for CS-GA, BFS-GA, and BS-GA were 41.00%, 37.41%, and 23.41%, respectively. Complexation enhanced the short-range molecular order and increased the particle size of gelatinized starch, with increments of 37.93%, 31.90%, and 19.81%, respectively. It also reduced thermal stability, gelatinization viscosity, gel hardness, and rapidly digestible starch (RDS) content, while delaying starch retrogradation and increasing resistant starch (RS) and slowly digestible starch (SDS) contents. Complexation protected GA from degradation, resulting in a bioaccessibility exceeding 90% for all complexes. Furthermore, antioxidant assays showed that the decline in DPPH radical scavenging during digestion increased with higher RS content. These findings provide a theoretical foundation and novel insights for the development of functional starch-based foods of these tropical starches.