Comparative study of color, pungency, and biochemical composition in chili pepper (Capsicum annuum) under different light-emitting diode treatments.

摘要

Colour and pungency are the 2 main factors of chilli peppers that determine their quality and final market price. In this study, effects of light-emitting diodes (LED) on fruit colour and primary and secondary metabolites (capsaicinoids) in chilli cv. Cheonyang were investigated. HPLC analysis of acetonitrile extracts of chilli fruits revealed enhanced capsaicinoid contents in blue LED (180 +or- 6.32 mg/100 g) when compared with fluorescent light (54 +or- 3.12 mg/100 g). However, colour of chilli peppers was remarkably changed under different light treatments. Among these, high ASTA colour values and chromatic parameters (L*, a*, b*, C* and H degrees ) were recorded under red plus blue LED, further indicating red plus blue LED is responsible for most vivid colour development compared with monochromatic red or blue LED. In addition, total carbohydrate (22.32 mg g--1 fresh wt. (FW)), reducing sugars (8.27 mg g--1 FW), starch (14.05 mg g--1 FW), carotenoids (6.15 mg g--1 FW) and protein (4.83 mg g--1 FW) were found to be significantly high under red plus blue LED. Results showed that there were significant differences in plant growth and production of various metabolites among the different LED. Furthermore, blue LED showed a relatively higher rate of capsaicinoid production and red plus blue LED produced striking colour development in chilli peppers. Therefore, it is suggested that these results might serve as an alternative strategy for nutritional improvement (colour, oleoresin and pungency) of chilli peppers.