Ethanol and Methyl Jasmonate Fumigation Impact on Quality, Antioxidant Capacity, and Phytochemical Content of Broccoli Florets during Storage

Abstract

Broccoli is a vegetable that offers valuable components, such as glucosinolates (GLS), flavonoids, and hydroxycinnamic acids (HCA), for our daily food intake. These substances have been associated with reducing the risk of cancer and cardiovascular diseases (CVD). Broccoli florets are also highly perishable, given their elevated respiration rates and their sensitivity to ethylene. Experiments have been carried out on broccoli to investigate the consequences of abiotic stress post-harvest treatments in retarding the senescence process. Nevertheless, the influence of these treatments on the phytochemicals of broccoli has not been extensively examined. Florets of broccoli (Brassica oleracea) were exposed to an atmosphere consisting of 10,000 µL.L−1 ethanol at room temperature for 30 min and 120 min. The exposure to methyl jasmonate (MeJA) treatments was carried out at room temperature using 1 µL.L−1 for 45 min and 180 min. The yellowing of florets was delayed using 10,000 µL.L−1 of ethanol at both exposure times as compared to untreated florets, and the chlorophyll titers were also superior with both doses over the control. The total phenols of the florets increased by 15% and 18% with the application of the hormetic and high doses, respectively, throughout the storage period compared to unexposed broccoli. The GLS and HCA yields were also increased by both ethanol doses. The exposure of florets to 1 µL.L1 MeJA for 45 min resulted in delayed yellowing of florets; however, longer exposures resulted in yellowing after 21 d and significantly (p < 0.05) increased respiration rates relative to untreated florets. Overall antioxidant capacity of the florets was significantly reduced with both doses of methyl jasmonate; however, HCA titers were increased at both doses. The amount of total glucobrassicins within broccoli was increased following exposure of florets to both doses, but no significant differences in glucoraphanin content were observed. As a conclusion, the ethanol treatment could indeed delay senescence and lead to the induction of phytochemicals. In contrast, MeJA’s effect on quality is not quite substantial; it can, however, be used to improve the phytochemical content of florets, particularly indole-type GLS.

Keywords

• broccoli
• ethanol
• methyl jasmonate
• glucosinolates
• hydroxycinnamic acids