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

In this study , resistant starch (RS), ty pe 3, was prepared by the auto- claving and de branching of nor mal maize st arch isolated fro m a selecte d ZP genotype. The objectives of this study were to optimize both starch autoclaving and debranc hing with pullulan ase (Pro mozymeBrewQ) for the production o f RS. Autocl aving at 120 ° C (3 0 min) increa sed the RS co ntent of all samples, whereas freezing at -20 ° C did not have an o bvious effect on the RS cont ents. The highe st RS y ield in the au toclaved starch sa mples was 7 .0 % after three autoclaving-cooling cycles. After pullulanase debranching at 50 °C and retro- gradation at 4 °C, the RS y ields ran ged fro m 10.2 to 25.5 % in all sa mples (depending on the hy drolysis t ime). D ebranched st arch samples with a maxi- mum RS yield of 25.5 % were obtained after a debranching time of 2 4 h. Th is study sho wed t hat st arch fro m the selected Z P maize gen otype is suitable for pullulanase tre atment and RS preparation b ut that additio nal studi es wit h a greater number of different treatments (incubation time/temperature) are neces- sary to manipulate and promote crystallization and enhance RS formation.