S24 - Session O1 - Tryptophan, serotonin, and melatonin in banana cultivars during different ripening stages

Authors: Mengdi Wu *, Melissa Fitzgerald, Tim O'Hare

Melatonin, as a dietary supplement is currently the most popular product for resolving issues with insomnia. With the growing debate on the safety of synthetic dietary supplements, a natural source of melatonin has become increasingly valuable. The synthesis of melatonin in both animal and plants is based on the precursor, tryptophan. Bananas, with high phyto-tryptophan content, can be assumed as a potentially good source of melatonin. In this study, tryptophan, serotonin, and melatonin in peel and pulp of twenty-one different banana varieties are identified and quantified in freeze-dried powder samples with three different ripening stages using UHPLC-MS and LC-MS/MS QTRAP® 5500. The results presented the highest tryptophan and melatonin level in Sucrier Terema as 341.56 +- 22.37 µg/g tryptophan in the yellow pulp sample and 48.73 ng/g melatonin content in the overripe pulp sample. The highest serotonin level is found in Pisang Kel and Pisang Gajih Merah - greater than 600 µg/g in the yellow banana peel. There are varying levels of tryptophan, serotonin and melatonin content in the peel and pulp in 21 banana cultivars, but relatively lower levels of tryptophan in the unripe stage of bananas is common. No linear relationship can be seen between the amount of tryptophan and its derivative serotonin and melatonin in any specific parts and stages in the results base of these different bananas, which indicates the tendency of synthesis and degradation of these compounds vary in each cultivar.