Brassinolide soaking and preharvest UV-B radiation influence the shelf life of small black bean sprouts.

This study explored the effects of brassinolide (BR) soaking, preharvest ultraviolet-B (UV-B) radiation, and their combined treatments on physiological characteristics, chlorophyll fluorescence, and quality of small black bean sprouts during storage. Results indicated that the combined treatments significantly enhanced contents of flavone, free amino acid, and photosynthetic pigment, and activities of phenylalanine ammonia lyase (PAL) and 2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging in sprouts stored for 5 days compared with BR treatment alone. The combined treatments significantly increased total phenols content and PAL activity, and reduced malonaldehyde content in sprouts compared with UV-B radiation alone. The inhibitory effect of BR or UV-B on fluorescence of photosystem II was weakened by their combined treatments. Comprehensive analysis indicated that the combined treatments could be used to maintain postharvest small black bean sprouts with high levels of nutritional ingredients by probably keeping high photosynthetic capacity, PAL activity, and DPPH radical scavenging rate in sprouts.