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Brassica vegetables are a source of many biologically active compounds, including glucosinolates (GLS). At present, GLS attract a special attention because of their healthy properties. Four Brassica vegetables: cauliflower, Romanesco-type cauliflower, Brussels sprouts, and broccoli were examined. Analyses of GLS were done in raw, sous-vide cooked, traditionally cooked, and steamed vegetables as well as in samples stored for 5 days at 2 ± 1 °C. In the examined vegetables, 9 GLS were identified. The content of vitamin C was also determined. Moreover, microbiological analyses were performed. Among the investigated vegetables, the highest content of GLS was observed in the steamed samples. The traditional cooking of broccoli and Romanesco-type cauliflower causes a significant decrease of GLS as compared to the raw materials. The same explicit tendency was also observed in the case of cooking by the sous-vide method of Romanesco-type cauliflower and Brussels sprouts. Brussels sprouts, cooked by the sous-vide method, contained almost 40% less GLS than those cooked in water. Storage of the treated vegetables at 2 ± 1 °C led to a further reduction of the GLS level. It must be emphasized that the highest losses were observed in broccoli after sous-vide cooking (over 30%). Our results indicate that sous-vide method can be an advantageous technique of processing broccoli destined only for direct consumption. [ABSTRACT FROM AUTHOR]

The effect of different cooking times on the GLS content in white cabbage ( Brassica oleracea L. var. capitata f. alba) was determined. Cooking of cabbage for 5–30 min caused a gradual decrease in the GLS content. The most efficient reduction of the GLS content (by about 35%) occurred during the first minutes of cooking. As the cooking time was extended by another 5 min, each time the GLS content decreased by 10–15%. Higher losses in indole GLS, as compared to those of aliphatic ones, resulted from more efficient diffusion of those compounds to cooking water. The GLS content in cooking water, irrespective of the cooking time of white cabbage, remained rather stable, whereas the content of indole GLS was between 3.5- and 4-fold higher in comparison to that of aliphatic GLS. Taking into consideration the rate of changes in the content of particular GLS in cabbage and the GLS content in cooking water, it can be stated that glucoiberin was more thermolabile than other GLS. [ABSTRACT FROM AUTHOR]