Inhibitory effect of black tea, lemon juice, and other beverages on salivary and pancreatic amylases: What impact on bread starch digestion? A dynamic in vitro study

Daniela Freitas (1) , Steven Le Feunteun (1)

1 GMPA - Génie et Microbiologie des Procédés Alimentaires

Certain food properties (ex.: pH, polyphenolic composition) can inhibit digestive amylases and thereby slow down starch digestion. Our aim was twofold. (1) To determine the impact of 21 beverages and condiments (coffees, teas, wines, vinegars and lemon juice) on salivary and pancreatic amylolysis: inhibition ranged from 10% to 100% in our experimental conditions. (2) To investigate the effect of one black tea and lemon juice (selected for their strong inhibitory capacity) on starch hydrolysis during dynamic oro-gastro-intestinal digestion of bread. Compared to water (control), the effect of black tea was limited to a ≈20% reduction of released oligosaccharides during the intestinal phase. Lemon juice had a remarkable effect, completely interrupting gastric amylolysis by salivary amylase via a preliminary acidification of gastric contents. These results provide a strong biochemical rationale for the development of dietary strategies to improve the glycaemic impact of starch-rich meals which could be tested in vivo.

Mots clés: starch; black tea; bread; in vitro study; saliva

Mots clés: jus de citron; étude in vitro; thé noire; digestion; pain; boisson; the noir; amidon; amylase pancréatique; salive

Domaines: Alimentation et Nutrition; Ingénierie des aliments

Daniela Freitas, Steven Le Feunteun. Inhibitory effect of black tea, lemon juice, and other beverages on salivary and pancreatic amylases: What impact on bread starch digestion? A dynamic in vitro study. Food Chemistry, 2019, 297, pp.124885. ⟨10.1016/j.foodchem.2019.05.159⟩. ⟨hal-02265921⟩