Stability of anthocyanins in bokbunja (Rubus occidentalis L.) under in vitro gastrointestinal digestion.

Food Chem. 2018 Nov 30;267:157-162. doi: 10.1016/j.foodchem.2018.02.109. Epub 2018 Feb 21. Ryu D1, Koh E2. Author information 1 Major of Food & Nutrition, Division of Applied Food System, Seoul Women's University, Seoul 01797, Republic of Korea. 2 Major of Food & Nutrition, Division of Applied Food System, Seoul Women's University, Seoul 01797, Republic of Korea. Electronic address: kohem7@swu.ac.kr. Abstract The stability of anthocyanins in bokbunja (Rubus occidentalis L.) extract was investigated using an in vitro simulated gastrointestinal digestion. Ethanolic extract from bokbunja was digested with pepsin/HCl for 2 h at 37 °C, followed by pancreatin/bile salts for 2 h at 37 °C. Four anthocyanins including cyanidin-3-glucoside, cyanidin-3-sambubioside, cyanidin-3-xylosylrutinoside and cyanidin-rutinoside were identified in the bokbunja extract. The total anthocyanin content of bokbunja was 3.76 mg cyanidin-3-glucoside equivalents/g fresh weight (FW). Gastric digestion had no significant effect on anthocyanins. However, intestinal digestion substantially decreased anthocyanins up to 1.70 mg/g FW, corresponding to 45% of that in the bokbunja extract. This indicates that about half of anthocyanins can reach an intestinal tract. In addition, a new compound comprised of cyanidin-3-glucosdie, catechin and acetaldehyde in a separated study was observed after in vitro gastrointestinal digestion. This shows that anthocyanins could be transformed into other compounds with different biochemical properties. KEYWORDS: Anthocyanin; Bokbunja; Cyanidin; In vitro digestion; Stability