In Vitro and In Vivo Starch Digestibility and Quality of Bread Substituted with Acid and Heat-Moisture Treated Sweet Potato Starch

The objective of this study is to investigate in vitro and in vivo starch digestibility and glycemic index (GI), and the quality of bread supplemented with 20% of citric acid and heat-moisture treated sweet potato starch (20MSB) as compared to those of breads made from wheat flour with and without supplementation of 20% of native sweet potato starch (WFB and 20NSB, respectively). Resistant starch content of the 20MSB is 34.2%, significantly higher than those of the WFB (13.7%) and 20NSB (20.2%). The 20MSB exhibits lower blood glucose response in mice after 180-min intake as compared to the WFB and 20NSB. GI values of the WFB, 20NSB, and 20MSB are 100, 94, and 68.9, respectively. The wheat flour substituted with 20% of modified starch has significantly lower peak and final viscosities than those of the wheat flour. The 20MSB has lower specific volume and higher hardness and gumminess than the WFB or 20NSB. However, the results of sensory evaluation showed that the color, appearance, texture, and odor of the 20MSB are not significantly different from those of the WFB and 20NSB. As a result, the substitution of 20% modified starch is acceptable to make bread with high resistant starch content and medium GI.