In vitro availability of flavonoids and other phenolics in orange juice.
Hand-squeezed navel orange juice contains 839 mg/L phenolics, including flavanones, flavones, and hydroxycinnamic acid derivatives. The flavanones are the main phenolics in the soluble fraction (648.6 mg/L) and are also present in the cloud fraction (104.8 mg/L). During refrigerated storage of fresh juice (4 degrees C), 50% of the soluble flavanones precipitate and integrate into the cloud fraction. Commercial orange juices contain only 81-200 mg/L soluble flavanones (15-33%) and the content in the cloud is higher (206-644 mg/L) (62-85%), showing that during industrial processing and storage the soluble flavanones precipitate and are included in the cloud. An in vitro simulation of orange juice digestion shows that a serving of fresh orange juice (240 mL) provides 9.7 mg of soluble hesperidin (4'-methoxy-3',5,7-trihydroxyflavanone-7-rutinoside) and 4.7 mg of the C-glycosylflavone vicenin 2 (apigenin, 6,8-di-C-glucoside) for freshly squeezed orange juice, whereas pasteurized commercial juices provide 3.7 mg of soluble hesperidin and a higher amount of vicenin 2 (6.3 mg). This means that although orange juice is a very rich source of flavanones, only a limited quantity is soluble, and this might affect availability for absorption (11-36% of the soluble flavanones, depending on the juice). The flavanones precipitated in the cloud are not available for absorption and are partly transformed to the corresponding chalcones during the pancreatin-bile digestion.
Departamento de Ciencia y Tecnología de Alimentos, CEBAS (CSIC), P.O. Box 4195, 30080 Murcia, Spain.
A
A
Gil-Izquierdo
M I
MI
Gil
F
F
Ferreres
F A
FA
Tomás-Barberán
D001628:Beverages / Q000032:analysis*; D001682:Biological Availability; D002957:Citrus / Q000737:chemistry*; D004063:Digestion; D005419:Flavonoids / Q000032:analysis* / Q000493:pharmacokinetics; D005511:Food Handling; D006801:Humans; D007408:Intestinal Absorption; D010636:Phenols / Q000032:analysis* / Q000493:pharmacokinetics
D005419:Flavonoids; D010636:Phenols