[Effects of Red Light-Emitting Diode (LED) on the Postharvest Yellowing Change of Broccoli]

As an important factor affecting the growth and development of plants, light gives wide range regulating effects on physiological metabolisms, photosynthesis characteristic, quality and aging of plants during the growth . However, the research whether light can improve the quality of fruits and vegetables and prolong the storage period of is rarely reported home and abroad. Three monochromatic light , red, blue and green were used to the irradiation of broccoli. It was found that the inhibitory effect of red light could inhibit yellowing of postharvest broccoli better than that of blue light while green light could accelerate the yellowing, therefore this paper focused on the yellowing inhibitory effect of LED monochromatic red light on postharvest broccoli. The LED monochromatic red light with wavelength (625±5)nm, light intensity (100±5)Lx was used to provide continuous irradiation to broccoli with no light treatment as control. The results showed that: LED monochromatic light could inhibit the increase of chromatic aberration L value. The chromatic aberration -a/b value was maintained and the chlorophyll degradation was delayed. Meanwhile, the broccoli commodity was effectively maintained because of the delay of the respiration peak and the reduction of respiratory intensity as well as ethylene release rate . Correlation analysis showed that, after red LED monochromatic light treatment of broccoli, a positive very significant correlation (p<0.01) was found between the ethylene release rate and yellowing index. Compared with conventional no-light, treatments of LED monochrome red could extend the storage period around 5d for broccoli, and the results can provide a theoretical basis for cold storage of Broccoli.