Differential glucose bioaccessibility from native and modified taro-starches in the absence or presence of beet juice

Abstract

The speed of starch-digestion defines peak blood-glucose concentrations. Slow digestion is beneficial for diabetic individuals. To investigate the effects on blood-glucose it is important to be able to predict the amount of digestible starch. Therefore, the aim of this study was to compare the digestibility of different starches in a validated in-vitro model of the upper gastrointestinal (GI) tract. Digestion was performed in the TNO dynamic, computer-controlled in-vitro model of the upper GI-tract (TIM-1). Release of glucose was measured over time. Products tested were taro-flour, native-, and modified taro-starch. The latter two were also tested with beet-juice adsorbed. These were compared to wheat-flour and a glucose-solution. Modified taro-starch showed a similar glucose-bioaccessibility as wheat-flour (81–83%), while the other products tested had a lower bioaccessibility (60–75%). Adsorption of beet-juice affected digestibility of the modified taro-starch, but not the native-starch. Taro-based products can be used to lower plasma glucose concentrations in diabetic individuals.

Keywords

• taro
• starch
• in vitro digestibility
• in vitro gi tract model
• plasma glucose concentrations
• glycemic response
• diabetes