Phytochemical content in broccoli flower buds during postharvest storage and light treatments

Summary

The study aims to explore the effects of postharvest storage and light treatments on the phytochemical content in broccoli flower buds, and also to compare different methods for estimation of phytochemicals in fruits and vegetables. Freshly harvested broccoli heads (Brassica oleracea var. italica ‘Ironman’) were pre-stored for 4 days at 4°C in the dark before storage for 6 days at 4 or 10°C. Light treatments with visible light or a combination of visible light and UV-B irradiation were conducted during storage at 10°C and for 12 h day-1. The content of glucosinolates and flavonols in broccoli flower buds were determined by HPLC, whereas qualitative changes in phytochemical profile were studied using a non-targeted metabolomics approach based on UHPLC-ESI-qToF-MS. In addition, flavonol content during storage was monitored by repeated measurements using a non-destructive method based on chlorophyll fluorescence. The results show that the phytochemical content in flower buds of broccoli heads stored under different light and temperature conditions differs markedly in both quantity and composition.