Characterization of Vietnamese banana starch and its resistant starch improvement

Starch is accumulated in a green stage of banana and banana starch is considered to be a source of resistant starch. The aim of this study is to determine the physicochemical and functional properties of Vietnamese bananas, White Manzano (WM) and Dwarf Cavendish (DC), and investigate amount of resistant starch after debranching and retrogradation of banana starch. The isolated starch granules were smooth, elongated oval with ridges or spherical and approximately 10-50 μm in diameter, depending on banana species as seen by a scanning electron microscope. Amylose contents of WMS were 30.3%, which was higher than that of DCS (26.5%). Both of banana starches exhibited the C-type crystalline structure, low swelling power and high α-amylase hydrolysis resistant capacity. The banana starch after debranching and retrogradation had the B-type structure with significantly improved resistant starch content. The native banana starch analyzed as eaten sample contained 11.2% of resistant starch, whereas the debranched starch had significantly higher amounts of resistant starch (31.8-48.1%). As a result, the debranched banana starch can be used as a functional food with high amount of resistant starch.