Determination of the melatonin content of different varieties of tomatoes (Lycopersicon esculentum) and strawberries (Fragaria ananassa)

Melatonin has recently been detected in various plants and foods. However, data regarding the food composition of melatonin are too scarce to evaluate dietary intake. This paper aims to identify melatonin unequivocally using LC-MS in a wide set of varieties of tomatoes (Lycopersicon esculentum) and strawberry (Fragaria ananassa). Furthermore, a validated LC fluorescence was developed. This is the first time melatonin has been identified in Bond, Borsalina, Catalina, Gordal, Lucinda, Marbone, Myriade, Pitenza, Santonio, Perlino, Platero, and RAF varieties of tomatoes, as well as in strawberry (Fragaria ananassa): Camarosa, Candonga, Festival, and Primoris. Melatonin concentration was shown to vary greatly depending on the tomato varieties and harvests (2009, 2010), ranging from 4.11 ng/g to 114.52 ng/g fresh weight. However, the four varieties of strawberries collected during the two harvests showed greater similarity in melatonin (1.38-11.26 ng/g fresh weight). (C) 2011 Elsevier Ltd. All rights reserved.