Influence of In Vitro Digestion on Composition, Bioaccessibility and Antioxidant Activity of Food Polyphenols—A Non-Systematic Review

Abstract

There is increased interest in following a healthy lifestyle and consuming a substantial portion of secondary plant metabolites, such as polyphenols, due to their benefits for the human body. Food products enriched with various forms of fruits and vegetables are sources of pro-health components. Nevertheless, in many cases, the level of their activities is changed in in vivo conditions. The changes are strictly connected with processes in the digestive system that transfigure the structure of the active compounds and simultaneously keep or modify their biological activities. Much attention has focused on their bioavailability, a prerequisite for further physiological functions. As human studies are time consuming, costly and restricted by ethical concerns, in vitro models for investigating the effects of digestion on these compounds have been developed to predict their release from the food matrix, as well as their bioaccessibility. Most typically, models simulate digestion in the oral cavity, the stomach, the small intestine and, occasionally, the large intestine. The presented review aims to discuss the impact of in vitro digestion on the composition, bioaccessibility and antioxidant activity of food polyphenols. Additionally, we consider the influence of pH on antioxidant changes in the aforementioned substances.

Characterization of Andean Blueberry in Bioactive Compounds, Evaluation of Biological Properties, and In Vitro Bioaccessibility

“…These results agree with those of other authors who found similar losses of (poly) phenols in the intestinal steps [ 51 , 52 ]. Among phenolic compounds, anthocyanins have been found to experience higher losses during gastrointestinal digestion than flavonols and caffeic acid derivatives, all of them being affected by enzymes, pH levels, and secretions in the digestive tract in real physiological conditions [ 53 ]. Once the release of phenolic compounds from their matrix into the intestinal lumen has been studied, the further step would be the study of their transport through the epithelium into the body and their availability to be metabolized and absorbed after reaching the colon.…”

“…Afterward, the antioxidant capacity found during the intestinal and final steps of the gastrointestinal digestion (64–69 µmol TE g −1 ) was significantly higher compared with that found during the initial and oral steps (41–42 µmol TE g −1 ). This fact could be explained by changes in the structural form of (poly) phenols in the intestine, affected by neutral pH and enzymatic activities, which promote multiple forms of metabolites in the intestinal lumen, such as phenolic acids, resulting in a higher ability to scavenge free radicals [ 53 , 54 ]. Finding phenolic compounds after intestinal digestion showed their availability to be metabolized and absorbed after reaching the colon.…”

Novel Technologies Based on Supercritical Fluids for the Encapsulation of Food Grade Bioactive Compounds

“…The exposure to external factors, like temperature, light, oxygen and pH, causes the loss of bioactive functionality. In addition, there is a growing amount of evidence that shows how many functional compounds can greatly lose their bioavailability after consumption during their flow through the gastrointestinal tract [ 9 , 10 ].…”

Nrf2/HO-1-inductive Preventive Effect of 3,5-dicaffeoylquinic Acid, Antioxidant Compound from Green Coffee Beans, on Dimethylnitrosamine-induced Liver Fibrosis in Rats

“…However, dietary polyphenols undergo massive degradation after an oral administration. Its therapeutic activity as an antioxidant is always under the question [6,19]. For example, bioavailability of gallic acid and isoflavones is only around 5%, and other flavan-3-ol (a catechin), flavanone, and quercetin glucoside shows lower than 5% of bioavailability [9].…”

“…Most polyphenols are extensively metabolized after an oral administration. The oral bioavailability of most polyphenols is too low, less than 5%, so appropriate therapeutic blood levels cannot be achieved [6].…”