Broccoli contains high levels of vitamins, anticancer compounds and antioxidant molecules. As a consequence, they have a high nutritional value. After being harvested, however, broccoli rapidly undergo senescence, a process characterized by the oxidation of lipids, the degradation of macromolecules and the generation of reactive oxygen species. Consequently, once harvested broccoli loses flavor and nutrients.

According to Hua Zhang, Heifei University of Technology, China, and co-workers the postharvest senescence is delayed if the broccoli is fumigated with hydrogen sulfide. The researchers demonstrated that this molecule, endogenously produced by broccoli to regulate physiological functions, alleviates the senescence-induced decrease in antioxidant molecules, such as ascorbate, carotenoids, and flavonoids. Furthermore, by stimulating the activity of antioxidant enzymes, H₂S lowered the accumulation of reactive oxygen species, such as superoxide anion and hydrogen peroxide. Similarly, H₂S alleviated the oxidation of lipids by decreasing the activity of lipoxygenases.

• Hydrogen Sulfide Alleviates Postharvest Senescence of Broccoli by Modulating Antioxidant Defense and Senescence-Related Gene Expression,
  Shi-Ping Li, Kang-Di Hu, Lan-Ying Hu, Yan-Hong Li, An-Min Jiang, Fang Xiao, Yi Han, Yong-Sheng Liu, Hua Zhang,
  J. Agric. Food Chem. 2014.
  DOI: 10.1021/jf4047122