Chlorine dioxide alleviates the yellowing process of broccoli by regulating chlorophyll degrading enzyme activity and gene expression.

During the postharvest storage of broccoli, yellowing becomes a problem that affects the nutritional value and market value of broccoli. The aim of this study was to investigate the effect of chlorine dioxide (ClO2) on chlorophyll degradation in postharvest broccoli. Broccoli heads were immersed in 100 mg L−1 ClO2 solution and then stored at 4°C for 25 days. The results showed that postharvest ClO2 treatment delayed the yellowing of broccoli, suppressed weight loss and relative electrical conductivity, and increased total soluble solid content, indicating that ClO2 treatment could delay the decline of broccoli quality. At the same time, ClO2 treatment also reduced the loss of chlorophyll content and suppressed chlorophyllase (CLH), pheophyllase (PPH) and pheophyllase a oxygenase (PAO) activity, which in turn inhibited the expression of BoCLH1, BoCLH2, BoCLH3, BoPPH, and BoPAO. In summary, the results indicated that ClO2 treatment could delay the yellowing rate and maintain the commercial value of broccoli during storage. Novelty impact statement: Chlorine dioxide (ClO2) treatment can delay yellowing and maintain the commercial value of broccoli. ClO2 treatment inhibited chlorophyll degrading enzyme activity in harvested broccoli. ClO2 treatment can downregulate the expression of chlorophyll degradation gene in harvested broccoli. [ABSTRACT FROM AUTHOR]