Effect of drying conditions on indole glucosinolate level in broccoli

Broccoli is interesting as raw vegetable for domestic use and as well as dehydrated powder due to content of numerous biologically active compounds — phytochemicals. We examined the influence of blanching and drying air temperature and velocity on glucosinolate composition and content under conditions which are usually applied in industrial processing of broccoli. Broccoli blanching prior to drying caused a significant decrease in the glucosinolate content, which additionally decreased during the drying process. Drying at 50 °C and 60 °C with air velocity of 2.25 m s−1 was the most favourable in most of the cases

Distribution of glucosinolates in some raw and processed Brassica vegetables grown in Croatia

The interest in food with chemoprotective properties has been steadily increasing due to many epidemiological studies indicating the lower probability of acquiring some kinds of cancer (e.g. colon, prostate, breast, cervical) in populations, whose diet includes large quantities of Brassica vegetables. The biologically active compounds in Brassica vegetables are the breakdown products of glucosinolates, including isothiocyanates, nitriles, thiocyanates, indoles and oxazolidinethiones from which indoles and isothiocyanates in particular have been implicated to have anticarcinogenic properties. The object of the present study was to investigate glucosinolates distribution as well as their losses during blanching and cooking in edible parts of white cabbage, cauliflower, kohlrabi and collard. In all vegetable, only indole glucosinolates as precursors of anticarcinogenic compounds were identified, while glucoraphane was not detected. In cauliflower and collard, proportion of indole glucosinolates was more then 90%, followed by kohlrabi (>70%) and white cabbage (>50%). Analysis of glucosinolates losses during blanching and cooking showed substantial decrease in all vegetables. The major losses were observed for cauliflower, around 60%, for cooked vegetable, followed by white cabbage (55%), kohlrabi (53%) and collard (44%). The losses after blanching were approximately 15% less then in cooked vegetables