2019 ASHS Annual Conference

Broccoli is a good dietary source of glucosinolates, flavonoids and hydroxycinnamic acids. These substances have been associated with prevention of cancer and cardiovascular diseases. But broccoli florets are also very perishable due to their high respiration rate and ethylene sensitivity. Postharvest treatments involving abiotic stresses have been evaluated to delay senescence in broccoli, however, the effect of these treatments on phytochemicals have not been completely explored. Broccoli (Brassica oleracea) florets were exposed to an atmosphere containing 10,000 ppm of ethanol at room temperature for 30- and 120-min. Exposure to methyl jasmonate (MeJA) treatments was done at room temperature using 1 ppm for 45 and 180 min. Yellowing of the florets was delayed using 10,000 ppm of ethanol on both exposure times compared with untreated florets, and chlorophyll titers were also superior with both doses compared with the control. Total phenols of florets increased by 15 % and 18 % with the application of the hormetic and high dose, respectively over the storage compared with unexposed broccoli. The titers of glucosinolates and hydroxycinnamic acids were enhanced by both doses of ethanol as well. Exposure of florets to 1 ppm of MeJA for 45 min delayed the yellowing of florets, however longer exposures produced yellowing after 21 days and significantly (p<0.05) increased respiration rate compared with non-treated florets. The total antioxidant capacity of florets was considerably reduced by both doses of methyl jasmonate; however, titers of hydroxycinnamic acids increased with both doses. The amount of total glucobrassicins in broccoli increased after the exposure of florets to both doses, but not significant differences were observed in glucoraphanin content. In conclusion, ethanol treatments can effectively delay senescence and induce phytochemicals. In contrast, the effect of MeJA on quality is not substantial, however, it can be used to improve the phytochemical content of florets, especially of indole type