Pulses of low intensity light as promising technology to delay postharvest senescence of broccoli

• Published in: Postharvest biology and technology 2018-08, Vol.142, p.107-114
• Main Authors: Favre, Noelia, Bárcena, Alejandra, Bahima, José Vera, Martínez, Gustavo, Costa, Lorenza
• Format: Article
• Language: English
• Subjects: Biodegradation; Broccoli; Chlorophyll; Chloroplasts; Degradation; Delay; Irradiance; Light intensity; Light quality; Luminous intensity; Molecular chains; Photosynthesis; Phytochromes; Proteins; Red light; Senescence; Sugar; Sugars; Technology; Vegetables; White light; Yellowing
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2017.11.006

•Pulses of low intensity white light were efficient to delay broccoli postharvest senescence.•Light treatment delayed degradation of both types of chlorophyll.•Light treated samples had higher sugar level than not irradiated heads.•The retention of sugars was independent of quality of light used in light treatment.•Red and far red light have the opposite effect on chlorophyll and protein degradation. Visible light irradiance may be a useful technology to delay postharvest senescence of green vegetables. In this work, we studied the effects of low-intensity white, red and far red light pulses on postharvest senescence of broccoli stored in the dark at 20°C. Daily exposure for 2h to 20–25μmolm−2s−1 of white light delayed yellowing and retained chloroplast components (chlorophyll and soluble proteins). The utilized light intensity was insufficient to re-initiated photosynthesis since total sugar content was lower than initials in irradiated florets. Light treatment resulted in a slower loss of sugars in comparison with the untreated samples, but was not affected by light quality. The effects of red light treatment on chlorophyll a and soluble protein degradation were similar to white light, and opposite to far red light. However, these treatments did not delay chlorophyll b degradation, suggesting that phytochromes could be involved in molecular mechanism of chlorophyll a and soluble protein degradation, but not of chlorophyll b.