Effect of Maturity, Processing, and Storage on the Furanocoumarin Composition of Grapefruit and Grapefruit Juice

Since the early 1990's, grapefruit juice has been implicated in drug interaction with various furanocoumarins (FCs) now associated with the effect. Although FCs are present in various fruits and vegetables, it is their presence in grapefruit that has attracted the most attention. Studies have shown that FCs in grapefruit juice can vary significantly and from multiple causes. Most of all, FCs are stress-induced molecules, their levels affected by many factors ranging from UV exposure to insect infestation. There are also varietal and seasonal factors. In this study, juice processing and storage parameters were investigated. Prolonged fruit storage prior to processing and most steps involved in juice processing had little influence on the levels of 6',7'-dihydroxybergamottin (DHB), paradisin C, or bergamottin. However, products that were hot filled or stored at room temperature had lower amounts of DHB and paradisin C and higher amounts of bergaptol compared to juices that were not hot filled and stored at refrigerated temperatures. Both DHB and paradisin C are potent CYP3A4 inhibitors, while bergaptol is a very weak inhibitor. Bergamottin amounts decreased to a lesser extent. Therefore, grapefruit juice products that were hot filled or have been stored at room temperature for an extended period of time will have a reduced drug interaction potential. Practical Application This research provides information on how grapefruit drug interaction potential of grapefruit juice products are affected by processing and storage of juice products. Shelf stable products stored at room temperature in cans and glass containers will have lower levels of FCs compared to fresh products made from the same juice. Those wishing to minimize drug interaction potential in grapefruit products may do so by heating to pasteurization temperatures for 30 to 60 min. However, this will only lower and not eliminate the drug interaction potential.