Delivering anthocyanins in the gastrointestinal tract: processing conditions and food matrix effect

Over the last decade, many studies have demonstrated the potential benefits of using anthocyanins (ACs) in the prevention of metabolic syndrome. Nevertheless, most of these studies have only considered ACs as pure compounds rather than ingredients of bioactive-enriched foods. However, the AC -food matrix interaction could deeply impact on its digestibility and bioaccessibility, and hence, effectiveness. The objective of this study was to evaluate the effectiveness of different dairy and egg-based matrices on the delivering of ACs in the gastrointestinal tract under physiological relevant conditions. Two foods per matrix –milkshake and cream dessert for dairy matrices, and omelet and pancake for egg-based matrices – were produced under industrial conditions and fortified using a highly enriched AC powder obtained from red grapes (Vitis vinifera). After assessing the AC content in the foods by RP- HPLC and pH differential method, simulated gastro-intestinal digestions were carried out following the guidelines developed by INFOGEST (COST action FA 1005). This physiologically relevant model comprises an oral, gastric and intestinal phases, and takes into account many physiological factors. AC present in the soluble fraction at the end of the gastrointestinal digestion was quantified and bioaccessibility % of AC calculated for each food. The heat treatment applied during omelet and pancake production degraded around half of the AC added (47.39 and 58.58% of recovery respectively). However these products presented the best bioaccessibility values after in vitro digestion (44,14 and 40,91%). The solid texture of omelet and pancake could have protected AC from their degradation during the in vitro digestion process. In the non-cooked products, the low bioaccessibility values of AC observed after digestion (36,76% for milkshake and 15,83% for dessert) was compensated with the no losses of AC during its production. Although more experiments have to be done, it seems that non- cooked solid foods are the best option to maximize the delivering of AC in the gastrointestinal tract.