Response surface methodology for optimisation of soluble dietary fibre extraction from sweet potato residue modified by steam explosion

Abstract

Summary To make better use of sweet potato residue (SPR), a new pretreatment method, steam explosion ( SE ), can increase its content of soluble dietary fibre ( SDF ). Response surface methodology ( RSM ) was used to determine the SE variables for optimum SDF yield. The optimal conditions were a steam pressure of 0.35 MP a, a residence time of 121 s and a sieving mesh size 60. Under the optimised conditions, the content of SDF from SPR reached 22.59 ± 0.35%, an increase of 18.78% compared with that (3.81 ± 0.62%) from untreated SPR . The water‐holding capacity, oil‐holding capacity ( OHC ) and swelling capacity of SDF were improved by SE . Scanning electron micrograph ( SEM ) images demonstrated that SDF had become poriferous, loose and dilatants after SE treatment. This technology provides an efficient process for increasing the industrial production of SDF from SPR.