Effects of autoclaving and pullulanase debranching on the resistant starch yield of normal maize starch

Abstract

In this study, resistant starch (RS), type 3, was prepared by the auto-claving and debranching of normal maize starch isolated from a selected ZP genotype. The objectives of this study were to optimize both starch autoclaving and debranching with pullulanase (PromozymeBrewQ) for the production of RS. Autoclaving at 120 °C (30 min) increased the RS content of all samples, whereas freezing at -20 °C did not have an obvious effect on the RS contents. The highest RS yield in the autoclaved starch samples was 7.0 % after three autoclaving-cooling cycles. After pullulanase debranching at 50 °C and retro- gradation at 4 °C, the RS yields ranged from 10.2 to 25.5 % in all samples (depending on the hydrolysis time). Debranched starch samples with a maximum RS yield of 25.5 % were obtained after a debranching time of 24 h. This study showed that starch from the selected ZP maize genotype is suitable for pullulanase treatment and RS preparation but that additional studies with a greater number of different treatments (incubation time/temperature) are necessary to manipulate and promote crystallization and enhance RS formation. © 2010 Copyright (CC) SCS.