COMPOSITION AND CONTENT OF FLAVONOL GLYCOSIDES IN BROCCOLI FLORETS (BRASSICA-OLEARACEA) AND THEIR FATE DURING COOKING

The two main flavonol glycosides present in broccoli florets were iden tified as quercetin 3-O-sophoroside and kaempferol 3-O-sophoroside. Th ree minor glucosides of quercetin and kaempferol were also detected, n amely isoquercitrin, kaempferol 3-O-glucoside and a kaempferol digluco side. The sophorosides of quercetin and kaempferol were present in raw florets at a level of 65 mg kg(-1) and 166 mg kg(-1) fresh weight, re spectively. The total content of quercetin and kaempferol glycosides e xpressed as aglycone was 43 and 94 mu g g(-1) fresh weight, respective ly, and these agree with other recently published data. During the coo king process only 14-28% of the individual glucosides were retained in the cooked tissue, the remainder being largely leached into the cooki ng water with only a small loss attributed to the formation of the res pective aglycones. (C) 1998 SCI.