• Biphasic digestogram;
  • gastric-pancreatic digestion;
  • glucometry;
  • in vitro starch digestion;
  • potassium release;
  • resistant starch


Twenty samples of sweet potato from Papua New Guinea, made up of cultivars 3-mun, Carot kaukau, Wahgi besta, Nillgai, Baiyer kaukau, and 1-mun from three provinces, three farmers, and three locations, were subjected to an in vitro starch digestion procedure. Digestion of starch was studied by glucometry, while potassium release was monitored using electrochemistry. The potassium content of the nondigested samples ranged from 4 to 17 mg g−1 dry solids, while the starch content was from 47 to 80 g per 100 g dry solids and independent of G × E effects. In vitro starch digestibility (2–75 g digested starch per 100 g dry starch) significantly (P < 0.05) varied with time in a nonlinear manner with biphasic digestograms. Potassium release was independent of time in in vitro gastric and pancreatic regions, but more potassium was released during pancreatic than gastric digestion. Results suggest differences in resistant starch and bioavailability of (micro)nutrients that could influence utilisation of sweet potato.