Impact of α-amylase and maltodextrin on physicochemical, functional and antioxidant capacity of spray-dried purple sweet potato flour

BACKGROUND: Purple sweet potato flour could be used to enhance food products through colour, flavour and nutrients. Purple sweet potato flour has not yet been prepared with maltodextrin and amylase treatment using spray drying. Thus, the investigation was to evaluate the effect of various levels of maltodextrin (30 and 50 g kg(-1) w/v), amylase (3 and 7 g kg(-1) puree) and combined with maltodextrin and amylase on the physicochemical, functional and antioxidant capacity of spray dried purple sweet potato flours. RESULTS: Amylase and amylase with maltodextrin-treated flours had a higher anthocyanin and total phenolic content than the control and maltodextrin-treated flours. However, the antioxidant capacity was higher in the control and maltodextrin-treated flours compared to the amylase and amylase with maltodextrin-treated flours. The control had a higher water absorption index and lower water solubility index compared to the maltodextrin and combined with amylase and maltodextrin-treated flours. On the other hand, maltodextrin increased whereas alpha-amylase decreased the glass transition temperature. With respect to morphology, the particles of amylase-treated flours were smaller than the control and maltodextrin-treated flours. CONCLUSION: The results showed that good quality flour could be prepared by combining 30 g kg(-1) maltodextrin and 7 g kg(-1) amylase treatment. (C) 2009 Society of Chemical Industry