The interaction between starch and polyphenol would increase the bioaccessibility of those bioactive compounds. Previous studies have been conducted with pure polyphenols, but the use of medicinal plants, rich in bioactive compounds, able to complex with starch, is growing. The present study aimed to analyze the complex formation between the extract of a medicinal plant (Amphipterygium adstringent, AA) and high amylose starch (HA). The total polyphenol content (TPC), and antioxidant capacity (AC), besides X-ray diffraction pattern, differential scanning calorimetry, Fourier transform infrared spectroscopy (FTIR), and starch hydrolysis rate were evaluated in the AA-HA and compared with those of the complex gallic acid (GA)-HA.
The AA-HA complex had higher TPC than GA-HA, despite their rather similar AC. The increased crystallinity and short-range order of the HA confirmed the formation of the complex with AA. This complex required higher enthalpy (2.0 J/g) than its respective HA control (0.52 J/g) for the gelatinization and the in vitro starch hydrolysis suggests the formation of resistant starch.
The extract of medicinal plants can form complexes with amylose, which has antioxidant properties, besides increasing the resistant starch.
Complex formation between HA and extract of medicinal plants is feasible for increasing the release of the bioactive compounds after digestion.