Continuous flow process to make fermented cassava starch substitute: I. Physicochemical and functional properties

Abstract

The Brazilian fermented cassava starch (polvilho azedo) is prized as a raw material for fast food preparation. Its traditional production by natural fermentation and exposure to sunlight favors contamination and impurities, in addition to depending on the climate. The literature explains the characteristic expansion of polvilho azedo as a reaction of the lactic acid produced during fermentation and sun radiation. With the aim to evaluate a commercial continuous flow process, a modular lamp (UV-C) was evaluated to substitute exposure to sunlight. The selected doses were 1,000, 5,000 and 10,000 Joules per liter (J l-1). Native cassava starch suspension in water at 6% (dry basis) was adjusted to 4% lactic acid (dry basis) and exposed to UV-C radiation: (a) without lactic acid, (b) with lactic acid reaction for 1 hour, (c) with ultraviolet radiation, in addition to the combination of (ac) and (bc). The results showed that only the combination of acidification and ultraviolet radiation (bc) allows an expansion (11 cm3 g-1) higher than the commercial polvilho azedo (8.24 cm3 g-1) adopted as standard. It was concluded that is possible to achieve a substitute for fermented cassava starch by acidification of native cassava starch with lactic acid in a continuous flow system starting with a dose around 5,000 J l-1 of UV-C radiation.