Abstract:In order to improve the post-harvest storage quality of broccoli (Brassica oleracea), and provide new approaches for preservation of fresh vegetables in practice, this research examined the preservative effects of different wavelengths of monochromatic light-emitting diode (LED) on the quality of broccoli stored at a low temperature: Red (642 nm), yellow (591 nm), green (519 nm), blue (464 nm), and purple (435 nm); treatment time 24 h/day ? 12 day dark conditions used as a control. A comprehensive evaluation was conducted based on sensory, physico-chemical, nutritional and microbial analyses (including color attributes, chlorophyll content, reducing sugar content, total soluble solid content, and total number of colonies),to assess the post-harvest storage quality of broccoli over the storage. Results showed that different monochromatic LED treatments could delay the decline of nutritional quality of broccoli during storage. After 12 days of storage, the green LED (519 nm) could maximally maintain the sensory quality of broccoli, inhibit the increase of brightness L*, delay the degradation of chlorophyll, reducing sugar and soluble solids, and in the meantime, suppress effectively the microbial growth, delay the decrease of hue angle (H-value) and maintain the content of vitamin C. Therefore, the green LED treatment was the most effective to maintain the storage quality of broccoli over the low-temperature storage and extend its shelf life.
