A novel W/O/W double emulsion co-delivering brassinolide and cinnamon essential oil delayed the senescence of broccoli via regulating chlorophyll degradation and energy metabolism

The postharvest senescence accompanied by yellowing limited the shelf-life of broccoli. In this study, we developed a novel W/O/W double emulsion co-delivering brassinolide and cinnamon essential oil and applied it to broccoli for preservation. Results showed that double emulsion prepared by whey protein concentrate-high methoxyl pectin (1:3) exhibited best storage stability with largest particle size (581.30 nm), lowest PDI (0.23) and zeta potential (−40.31 mV). This double emulsion also exhibited highest encapsulation efficiency of brassinolide (92%) and cinnamon essential oil (88%). The broccoli coated with double emulsion maintained higher chlorophyll contents and activities of chlorophyllase and magnesium-dechelatase were reduced by 9% and 24%, respectively. The energy metabolic enzymes (SDH, CCO, H+-ATPase, Ca2+-ATPase) were also activated, inducing higher level of ATP and energy charge. These results demonstrated W/O/W double emulsion co-delivering brassinolide and cinnamon essential delayed the senescence of broccoli via regulating chlorophyll degradation and energy metabolism.