Hormonal regulation and glucosinolate preservation in postharvest broccoli

Broccoli (Brassica oleracea L. var. Italica) is an important source of glucosinolates, bioactive compounds whose levels can be significantly affected during postharvest senescence. The study examines how different hormonal regulators associated with plant aging influence glucosinolate metabolism during broccoli storage.

For this purpose, broccoli heads were treated with 6-benzylaminopurine (BAP), ethephon, and 1-methylcyclopropene (1-MCP), and then stored for five days at 20 °C under dark conditions. Senescence progression was evaluated through surface color and chlorophyll content, together with analyses of glucosinolate profiles and gene expression associated with glucosinolate biosynthesis and degradation.

The results showed that postharvest storage caused rapid yellowing, chlorophyll loss, and a general reduction in glucosinolate content in control samples. However, BAP and 1-MCP treatments significantly delayed senescence, maintained higher chlorophyll levels, and reduced glucosinolate losses, particularly indolic compounds such as glucobrassicin and neoglucobrassicin.

In BAP-treated samples, glucobrassicin and neoglucobrassicin contents were 117 % and 93 % higher respectively than in control samples on day five of storage. In the case of 1-MCP treatment, the most notable differences were observed on day three, with glucobrassicin and neoglucobrassicin levels being 69 % and 66 % higher than untreated samples.

In contrast, ethephon accelerated senescence and promoted a greater decrease in both aliphatic and indolic glucosinolates. Gene expression analyses also revealed a general downregulation of genes involved in aliphatic glucosinolate biosynthesis during storage, whereas indolic glucosinolate pathways showed hormone-dependent responses according to the treatment applied.

Overall, the study indicates that senescence-associated hormonal regulation plays a central role in glucosinolate metabolism during broccoli postharvest storage and demonstrates that BAP and 1-MCP treatments are effective strategies for maintaining nutritional quality by delaying both senescence and glucosinolate degradation.

Source

Casajús, V., Fish, T., Civello, P., Thannhauser, T., Gómez Lobato, M., & Martínez, G. (2026). Glucosinolate Metabolism During Postharvest Storage of Broccoli Heads Treated with Ethylene, Cytokinins and 1-MCP. MDPI Horticulturae.