Melatonin in grapes and grape-related foodstuffs: A review

- Research progress since melatonin was first reported in grapes in 2006 is reviewed.
- Melatonin is found in most wine grapes, as well as in grape-related foodstuffs.
- Melatonin contents in grapes vary with many factors, including analysis technique.
- Melatonin in wine may originate from grapes or from the yeast fermentation process.
- Further research is needed to clarify the mechanisms of melatonin biosynthesis.

A decade has passed since melatonin was first reported in grapes in 2006. During this time, melatonin has not only been found in the berries of most wine grape (Vitis vinifera L.) cultivars, but also in most grape-related foodstuffs, e.g. wine, grape juice and grape vinegar. In this review, we discuss the melatonin content in grapes and grape-related foodstuffs (especially wine) from previous studies, the physiological function of melatonin in grapes, and the factors contributing to the production of melatonin in grapes and wines. In addition, we identify future research needed to clarify the mechanisms of grape melatonin biosynthesis and regulation, and establish more accurate analysis methods for melatonin in grapes and wines.