The impact of coupled acid or pullulanase debranching on the formation of resistant starch from maize starch with autoclaving-cooling cycles

Maize starch was treated by autoclaving-cooling cycles, coupled with acid or pullulanase hydrolysis to prepare resistant starch (RS). Debranching of retrograded or gelatinized maize starch with acid or pullulanase was studied to show the corresponding impact on RS formation. When maize starch was treated with three autoclaving-cooling cycles and retrograded maize starch was hydrolyzed at room temperature, with 0.1 mol L-1 citric acid for 12 h, analysis results showed that debranching of citric acid was helpful in RS formation for RS yield increased from 8.5 to 11%. Debranching of gelatinized or retrograded maize starch at 60 A degrees C with pullulanase at addition level of 3 PUN g(-1) starch showed a more favorable effect on RS formation. When gelatinized maize starch was hydrolyzed by pullulanase for 12 h and then treated with two autoclaving-cooling cycles, RS yield increased to 23.5%. If retrograded maize starch subjected to one autoclaving-cooling cycle was hydrolyzed by pullulanase for 10 h and then followed by two autoclaving-cooling cycles, RS yield elevated to 32.4%. The debranching effect of pullulanase on retrograded maize starch to help RS formation is obvious and most effective, indicating this treatment is applicable in RS preparation to increase the RS yield.