Improved Melatonin Content And Antioxidant Activity Of Mung Bean Sprout By Germination Under Salinity Incorporated With Exogenous Melatonin

Abstract

Melatonin is a natural hormone produced by the pineal gland in the brain to regulate human circadian rhythms. It is often used to treat sleep disorders, and as an antioxidant. High melatonin and antioxidant mung bean sprouts were produced. The effects of germination time, sodium chloride (NaCl) stress, exogenous melatonin treatment on the improvement of endogenous melatonin, total phenolic compounds (TPC) and antioxidant profiles of mung bean sprouts were evaluated using the response surface method (RSM). Eleven conditions of germination were generated using a fractional factorial design. The results indicated that all conditions led to a germination rate of over 92%. An increase in germination time, NaCl concentration, and exogenous melatonin resulted in the elevation of endogenous melatonin, TPC and antioxidant activity of sprouts. Optimal conditions for the germination of mung bean sprouts were 0.50% NaCl, 30 μM melatonin, with a germination time of 72 h. The experimental values under these conditions were 942.88 ng/g for melatonin, 1.83 mg/g for total phenolic content, 0.95 mg Trolox equivalent (TE)/g, for DPPH radical scavenging assay, and 11.02 mg TE/g, for total antioxidant capacity. Germination under these conditions is considered a potential process that could be adopted to produce ready-to-eat sprouts, or functional ingredients with high concentration of melatonin for the food industry.