Attached
Glucosinolates are a large group of plant secondary metabolites. They are common in all
economically important species of Brassicca vegetables. Reduced risk of certain cancers is
found to associate with consumption of Brassicaceae family vegetables which contain
glucosinolates. In the present study, four major glucosinolates (sinigrin, glucoraphanin,
glucotropaeolin and gluconasturtiin) were identified in the tested samples and quantified
using High Performance Liquid Chromatography (HPLC) combined with photodiode-array
detection (PDA). Accordingly, five most locally popular Brassica species namely, broccoli
(Brassica oleracea var. italica), white cabbage (Brassica oleracea var. cap itata) , red
cabbage (Brassica oleracea var. cap itata) , radish (Raphanus sativus) and cauliflower
(Brassicaoleracea var. botrytis) were analysed for their glucosinolates profile in raw,
cooked and in vitro digested samples. The stability of glucosinolates was evaluated in
selected vegetables under different cooking methods and in vitro gastrointestinal digestion
methods. It was observed that frying is the best method to preserve glucosinoItes in
vegetables, compared with soups or vegetables cooked with coconut milk. It was found that
the in vitro gastric digestion of vegetable varieties causes high losses In individual
glucosinoltes (~70%). After the pancreatin-bile salts mediated digestion, an additional
decrease in individual glucosinoltes was observed (~20%). When the Brassicca vegetables
were subjected to complete in vitro gastro intestinal digestion, the amount of glucosinolates
retained were approximately 10%. This high percentage of loss during the digestion process
could be due to the degradation of glucosinolates either to nitriles or to secondary reaction
products depending on the gastro intestinal pH conditions.
