Comparison of low pressure cold plasma and chemical elicitors as two approaches for enrichment of lentil sprouts with bioactive compounds

Production of functional foods containing health promoting phytochemicals is an attractive issue in food sector. Activating a plant's defense system by different biotic and abiotic stressors boosts the synthesis of bioactive metabolites. Using this method could be a solution for producing edible sprouts rich in nutraceuticals. Limited studies have been conducted on the production of functional legume sprouts using chemical elicitors, while the effect of cold plasma as a novel physical elicitor on the synthesis of bioactives in fresh sprouts has been neglected. Hence, this research aimed to compare the effect of low-pressure plasma (at different power levels and treatment times) and chemical elicitors (ascorbic acid, glutamic acid, chitosan, chitosan in glutamic acid, and NaCl) on enrichment of lentil sprouts with gamma-aminobutyric acid (GABA), phenolic and antioxidant compounds. First, cold-plasma at 30, 40, 50, and 60 watts was applied to the seeds for 5 and 10 min, then the seeds germinated for 48 and 72 h. In the second stage, the effect of irrigation of seeds with chemical elicitors during 48 h of germination was investigated. The highest amount of GABA (1476.26 ppm) was measured in lentil sprouts after plasma treatment at 40 watts, 5 min and further germination for 48 h, or irrigation of seedlings with chitosan (1425.32 ppm) and ascorbic acid (1427.99 ppm). The maximum phenolics content and antioxidant activity were observed at 30 watts, 5 and 10 min of plasma treatment and 48 h of sprouting respectively. As conclusion, both cold-plasma and chemical elicitors were effective in enhancing the bioactive content of lentil sprouts. The important point is to optimize the conditions of each method to obtain the maximum amount of the desired bioactive compounds.