Physicochemical properties and in vitro digestion of starches from different Dioscorea plants

Physicochemical properties (paste clarity, water-binding capacity, swelling power, solubility and thermal properties) and in vitro digestion of starches isolated from ten different Dioscorea plants were investigated. Moisture content ranged from 7.52% to 15.75% and protein content varied between 0.010% and 0.028%. All of the starches gave a typical C-type X-ray diffraction pattern except D.BY (CA-type pattern) and Dioscorea persimilis (B-type pattern) starches. The relative crystallinity of them varied from 12.02% to 51.68%. The starches displayed significant variability in thermal transition temperatures and susceptibility to in vitro digestion, and varied in rapidly digestible starch (RDS), slowly digestible starch (SDS), resistant starch (RS) contents, hydrolysis index (HI) and glycemic index (GI). The ten Dioscorea starch samples can be classified into two major clusters by hierarchical cluster analysis: one cluster with more D.PP, D.BY and D.RC, and another cluster with D. XM, D.M-1, D.M-2, D.TG, D.H, D.CJ and D.J.

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► The rhizomes of Dioscorea plants were collected according to geographical indications.
► Hydrolysis index and estimation of glycemic index were negatively related to crystalline degree.
► Dioscorea plants are classified by hierarchical cluster analysis based on their properties.