Changes in orange juice (poly)phenol composition induced by controlled alcoholic fermentation

Orange juice is a rich source of bioactive compounds. Fermentation processes have been carried out in fruits, resulting in products with higher bioactive compound contents than the substrates. The aim of this study was to evaluate changes in phenolic acids, flavones and flavanone derivatives during the alcoholic fermentation process (15 days) in orange juice and to optimize the fermentation time. A total of 45 (poly) phenolic compounds were detected by UHPLC coupled with a linear trap quadrupole (LTQ) and Orbitrap Elite series mass analyser (UHPLC-Orbitrap-MS/MS). We tentatively identified 21 hydroxycinnamic acids, including ferulic acid, caffeic acid, and sinapic acid, in addition to 18 hydroxycinnamic acid derivatives (7 ferulic acid derivatives, 8 caffeic acid derivatives, 2 sinapic acid derivatives, a p-coumaric acid derivative) as well as 2 hydroxybenzoic acid derivatives, a hydroxypropionic acid derivative and other compounds (citric acid, quinic acid, 3 quinic acid derivatives) for the first time in fermented orange juice. In addition, 16 flavonoids, 7 flavanones (didymin, hesperidin, narirutin and 4 narirutin derivatives), 7 flavonols (kaempferol derivatives) and 2 flavones (diosmetin, vicenin-2) were putatively identified in fermented orange juice for the first time. Total hydroxycinnamic acid, benzoic acid, flavones and flavonol derivative contents showed significant increases (7.9, 4.7, 18.3 and 24.5%, respectively) on day 11 of fermentation relative to the original juice. The optimum time for the procedure was 11 days, after which the highest content of (poly) phenolic compounds was reached. The potential beverage produced by alcoholic fermentation of orange juice would exert greater health effects in humans than the substrate, derived from both the (poly) phenolic content and the low level of alcoholic content.