Influence of drying conditions on functional properties of potato flour

Gel consistency, pasting behaviour, sedimentation volume and swelling and solubility of potato flour, prepared by two different drying methods were determined. The functional properties of flour were changed markedly in drum drying due to severe molecular degradation whereby its digestibility was also increased compared to native and hot air dried flour. Amylose content of drum dried flour increased and its soluble amylose was doubled as a result of processing. Processing further effected agglomeration of starch granules with altered morphological features. B-type X-ray diffraction pattern was obtained for the native starch whereas V-type patterns were observed for the processed samples. Crystallinity index of drum dried flour was much lower and indicated the loss of granular surface and crystallinity. The reduction in peak intensities of starch of processed samples was observed in ¹³C NMR though the basic molecular structure remained unaffected. From these results an optimum amount of processed potato flour is expected to be used to achieve desirable properties for product development.