Effect of Light Emitting Diode Radiation on Antioxidant Activity of Barley Leaf

Antioxidant activity of extracts of barley leaves cultivated by light emitting diode (LED) radiation such as red, far-red, blue, blue-red, green, yellow, and white light was investigated. After measuring length and weight of the leaves cultivated, barley leaves were extracted using 70% ethanol. The Hunter color value, total phenolic compounds, and 1,1-dipheny1-2-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salts (ABTS) radical-scavenging activities of extracts were determined. Lengths of samples cultivated by red and green light radiation were 13.7 and 13.6 cm, respectively. Hunter L*values of samples cultivated by red, far-red, and UVA radiation were 65.29, 67.55, and 67.57, respectively. The content of total phenolic compounds of samples cultivated by blue light radiation was 1.62 mg/L of sample. The DPPH radical-scavenging activities of samples cultivated by blue, green, UVA, and white light radiation were 64.28, 48.92, 55.95, and 48.72%, respectively. The ABTS radical-scavenging activity of samples cultivated by blue light radiation scored higher compared with those of samples cultivated with other LED lights. Antioxidant activities of barley leaves showed different results depending on harvest time. Application of LED radiation during re-cultivation after the first harvest showed increasing tendency on antioxidant activity of barley leaves.