Antioxidant Potentiality and Mineral Content of Summer Season Leafy Greens: Comparison at Mature and Microgreen Stages Using Chemometric

Nine summer season leafy greens viz., Amaranthus, bottle gourd, cucumber, jute, palak, poi, pumpkin, radish, water spinach, were evaluated for their antioxidants and mineral content at microgreen and mature stages. Among the antioxidants, total phenolics, total flavonoids, and ascorbic acid were quantified. Besides, antioxidant activities of the leafy vegetables were also measured using four in vitro assays viz., ferric reducing antioxidant power (FRAP), cupric reducing antioxidant power (CUPRAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Trolox equivalent antioxidant capacity assays (TEAC). In addition to this, the content of selected elements such as potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) was estimated. A wide variation was observed in the content of antioxidants and minerals. Variation was also observed for cultivar to cultivar as in case of Amaranthus. Results showed that the total phenolic content varied from 95.73 to 313.92 mg Gallic acid equivalent (GAE)/100 g in the mature vegetables, whereas the value varied from 25.00 to 152.10 mg GAE/100 g in microgreens. In fact, mature leafy vegetables were found to be significantly higher sources for total phenolics than microgreens. Likewise, a similar trend was observed for total flavonoids content and antioxidant activities. On the contrary, in all the species the concentration of K and Zn was significantly higher in microgreens than mature vegetables. However, no specific trend was observed in case of Fe, Cu, and Mn content. Based on antioxidant potentiality and mineral content, these leafy greens formed three distinct clusters; the first cluster represented by Amaranthus cv Local Green, jute, bottle gourd, and water spinach at mature stages. Jute was found to be the best, followed by bottle gourd, Amaranthus cv. Local Green, and water spinach.