A novel approach of LED light radiation improves the antioxidant activity of pea seedlings

Influence of light-emitting diode (LED) light on antioxidant activity of radiated pea seedlings was first studied using red (625-630 nm) and blue (465-470 nm) LED lights as light sources in an attempt to determine and compare the changes in chlorophyll and beta-carotene contents, and Trolox equivalent antioxidant capacity (TEAC, mu M). After radiation for 96 h, comparing to white light group, red light radiated seedlings displayed significant (p < 0.05) increases in stem length and leaf area, while blue light radiation significantly (P < 0.05) increased the stem length and seedling weight. Chlorophyll in leaves increased rapidly when seedlings were radiated by blue light but no significant (p > 0.05) difference was observed among light radiated seedlings after 96-h cultivation. beta-Carotene content of LED radiated leaves was significantly (p < 0.05) higher in red light (54.47 +/- 2.35 mu g/g) group than in the others. TEAC value of ethanol and acetone extracts (50 mg/mL) of 240 pieces of red light radiated seedlings cultured for 96 h reached 106.48 and 81.68 mu M, respectively, were higher than the other treatments. In conclusion, the contribution of red light to significant beta-carotene expression and antioxidant activity for nutrition and health benefits and blue light to seedling weight and chlorophyll induction of radiated pea seedlings are emphasized. (c) 2006 Elsevier Ltd. All rights reserved.