The Influence of Dietary Fiber (β-Glucan) on the Beneficial Effects of Phenolic Compounds from Chokeberry After Simulated Digestion In Vitro

Bioactive phenolic compounds released in the digestive tract have the potential to mitigate various diseases. However, they can be affected by dietary fibers. Our aim was to study the influence of β-glucan (dietary fiber) on the antiradical activity of phenolic compounds from chokeberry and its inhibition of α-amylase and α-glucosidase after digestion. These beneficial activities, helpful in many health issues connected to the digestive tract, depend on the constituents of food, such as dietary fibers, that surround these compounds and are not completely elucidated. Simulated digestion of chokeberry with or without the presence of β-glucan was conducted in vitro. The released phenolic compounds (RP-HPLC method), the antiradical activity (DPPH method), and the inhibition of α-amylase and α-glucosidase were determined after digestion. Chokeberry after gastric and intestinal digestion showed antiradical activity, and after intestinal digestion, it inhibited α-amylase and α-glucosidase. B-glucan decreased the amount of total phenolic compounds released (1800 to 1761 mg kg−1 fw) and bioaccessibility (60 to 59%) in the stomach (p < 0.05) and small intestine (1738 to 1637 mg kg−1 fw, 58 to 55%) (p < 0.05), decreased the antiradical activity, and weakened the enzyme inhibition. Principal component analysis clustered the released phenolic compounds and beneficial effects according to digestion with or without added β-glucan, confirming the influence of β-glucan on beneficial effects. Chokeberry polyphenols kept their beneficial effects in the stomach and small intestine in the presence of dietary fiber, which allows us to suggest that they show bioactivities even in the presence of other food constituents.