Loading...
Pairing acidic and starch-rich foods lowers glycaemic responses by inhibiting oro-gastric starch hydrolysis: Evidence from in vitro semi-dynamic digestion
Date
2025-8
Collections
Research Projects
Organizational Units
Journal Issue
Citation
Freitas, D., Le Feunteun, S. and Brodkorb, A., 2025. Pairing acidic and starch-rich foods lowers glycaemic responses by inhibiting oro-gastric starch hydrolysis: Evidence from in vitro semi-dynamic digestion. Food Research International, p.116551.
Abstract
Human studies over the past three decades have consistently shown that lowering the pH of starch-rich meals can significantly attenuate postprandial glycaemia. Based on our previous in vitro studies demonstrating the substantial contribution of salivary α-amylase during oro-gastric digestion of neutral-pH, starch-rich meals, we hypothesized that this effect is primarily mediated by the premature, acid-induced inhibition of salivary α-amylase during oral and/or gastric digestion. This study aimed to test this hypothesis by examining the starch digestion kinetics of food combinations from three independent human studies assessing the impact of combining acidic foods (white wine vinegar, pomegranate juice or kiwifruit) with bread or breakfast cereal. Five meals underwent semi-dynamic digestion in vitro using an adapted version of INFOGEST protocols. Samples were collected at all stages of digestion to determine the temporal profiles of starch release and hydrolysis into oligosaccharides. Approximately 40% of the total starch in bread was hydrolysed into oligosaccharides during oro-gastric digestion; however, this decreased to 15% - 20% (>50% reduction) with the addition of vinegar (p < 0.01) or pomegranate juice (p < 0.05). Similarly, for breakfast cereal, starch hydrolysis decreased from 35% to around 15% with kiwifruit (p <0.001 to <0.01). These results are consistent with the glycaemic attenuations reported in the literature for the same acidic meals, confirming our hypothesis and further substantiating existing knowledge on the relationships between meal pH, starch digestibility and glycaemic responses.