Organic acid bioavailability from banana and sweet potato using an in vitro digestion and Caco-2 cell model

Abstract

Introduction Organic acids from plant food have been shown to play an important role in the prevention of chronic diseases (osteoporosis, obesity), inherent to western diets, but little is known about their bioavailability in the small intestine, information that needs to be determined in order to quantify likely effects on human health. Methods An in vitro model of human digestion was carried out, comprising simulated oral, gastric and pancreatic digestion followed by an in vitro model of small intestine absorption using Caco-2 cell monolayers. As models for fruits and vegetables, freeze-dried or raw samples of banana and sweet potato were used. Results Organic acids have been found to be slowly released from the food matrix during simulated digestion of both banana and sweet potato, either raw or after freezedrying. In the Caco-2 cell assay, malic and oxalic acids were absorbed more than citric acid. Oxalic and citric acids, but not malic acid, were transported across the cell monolayer. The release and uptake of major organic acids from model fruits and vegetables using established in vitro simulation processes was not quantitative and varied with acid type.Conclusion Partial uptake is consistent with a dual nutritional role for organic acids as alkalinising agents (fraction which is taken up) and as modulators of large intestinal function (fraction which is not taken up in the small intestine). Studies of in vivo digestive release and uptake are needed in order to identify the contribution of organic acids to the nutritional value of fruits and vegetables.

The regular consumption of a polyphenol-rich apple does not influence endothelial function: a randomised double-blind trial in hypercholesterolemic adults

“…Although the bioavailability of polyphenols in fresh and freeze-dried fruits has not been compared, there is no indication that these would differ substantially. The bioavailability of organic acids of fresh and freeze-dried banana or sweet potato was compared in a recent publication, and no effect of freeze-drying could be seen (Sabboh-Jourdan et al, 2010). Freeze-dried fruits are also commonly used in animal studies with no notable effects on polyphenol bioavailability (Felgines et al, 2007).…”

Validation of an In Vitro Digestive System for Studying Macronutrient Decomposition in Humans3

“…So far, most in vitro digestion systems that included an absorption cell culture step simply focused on compound bioavailability and were not designed to determine physiological effects (1)(2)(3). Very few studies have concentrated on the functional properties of food components after digestion and absorption of nutrients (4).…”

“…According to the USDA nutrient database (no. 01211), bovine milk contains ;3.15 g protein, 3.27 g fat, and 5.05 g carbohydrates (lactose)/100 g milk (100 mL milk corresponds to 103 g). The major protein fractions in milk are caseins and whey proteins, accounting for 80 and 17% of total milk proteins, respectively.…”

Bioavailability of Phytochemicals

“…Organic acid provides organic anion important for metal binding and counteracting acidosis as well as preventing chronic diseases (Sabboh et al, 2011). Particular organic acids are apparently absorbed into plasma.…”

“…Most organic acids in tomato, mango, and papaya products are absorbed in in vitro caco-2 model but they are not found in the basolateral sides (Epriliati, 2008). On the other hand, citric acid and oxalic from banana and sweet potato are consistently found to be absorbed and translocated into basolateral sides in in vitro caco-2 model (Sabboh et al, 2011). The absorbed organic acids are much lower compared to the original levels in food materials, thus, the retained organic acids in particles may be useful for controlling pH in colonic fermentation because selection of microbes in the large bowel is important.…”