Characterization of a fibre-rich powder prepared by liquefaction of unripe banana flour

Abstract

The development of nutraceutical ingredients is of current interest for the food industry. A fibre-rich powder (FRP) was prepared by liquefaction of raw banana flour (RBF) and its chemical composition, water- and oil-holding capacity, and antioxidant capacity were evaluated. Total dietary fibre (TDF) was higher in FRP than in the RBF, but the total starch (TS), potentially available starch (AS) and resistant starch (RS) contents were lower in the processed product, since the liquefaction process involves granular disruption and starch hydrolysis, resulting in reduced TS and AS and increased TDF. The reduced RS content is also explained by the loss of granular integrity, which is the main factor responsible for the indigestibility of native banana starch. Total indigestible fraction content of FRP was relatively high, the soluble fraction being lower than the insoluble portion. A very fast reduction of DPPH was observed in the presence of FRP, indicating that polyphenols in this preparation efficiently quench free radicals. Tested at various temperatures, the FRP and RBF exhibited similar water-and oil-holding capacities. The main difference was observed in water-holding capacity at 80 °C, where FRP was less efficient than the raw material, a fact associated with starch gelatinization in RBF treated at that temperature. FRP might be a potential ingredient for development of products with high TDF and indigestible fraction contents, as well as important antioxidant capacity.