Impact of Melatonin Enrichment during Germination of Legumes on Bioactive Compounds and Antioxidant Activity

Abstract

This study assesses the impact of melatonin enriched watering on the germination of lentils (Lens culinaris L.) and kidney beans (Phaseolus vulgaris L.). The melatonin levels in lentil and bean sprouts measured by HPLC-MS/MS were more important than those found in other legumes and sprouts, being higher in lentil (1090 ng/g) than in kidney bean (529 ng/g) sprouts. This alternative germination promoted a significant increase of the development of radicles in comparison with the traditional germination. The decreases in the phenolic load were less accentuated than previously observed (lentil sprouts displayed 394 mg gallic acid equivalents (GAE)/100 g of dry weight (DW)), probably due to the protective effect of melatonin. The antioxidant capacity (oxygen radical absorbing capacity assay) increased in these sprouts, reaching 85 and 56 μmol of Trolox equivalents/g DW in lentils and beans, respectively. Hence, the melatonin-enriched foods exhibited potent free radical scavenger and antioxidant functions that may be used as a nutritional strategy to alleviate and prevent chronic and age-related diseases.

Keywords: antioxidant capacity; exogenous melatonin; germination; legumes; melatonin; phenolic compounds.