Glucosinolates in etiolated sprouts of sea‐kale (<i>Crambe maritima</i> L)

Abstract

Abstract Sea‐kale, a long‐forgotten vegetable, could make a resurgence due to its culinary attractiveness. Unfortunately, as with most cruciferous plants, its quality may be reduced owing to the presence of glucosinolates, mainly known for their antinutritional properties. The aim of this study was to evaluate the actual amount of these compounds found in edible sea‐kale sprouts, using qualitative and quantitative analysis by liquid chromatography carried out after treatment by freezing, blanching and cooking. Before treatment, the quantity of glucosinolates, of which more than 80% is represented by epi‐progoitrin, was found between 5.4 and 7.3 μmol g −1 of fresh matter. In this study, freezing then thawing causes a nearly complete decomposition of glucosinolates into nonidentified compounds which are most probably 5‐vinyloxazolidine‐2‐thionc and nitrites. Cooking for 4 min (blanching) brings about through leaching, a nearly 30% reduction. A greater decrease (76%) can be obtained with a cooking time of 20 min. The amount of glucosinolates found in sea‐kale was compared with that of other commonly used cruciferous vegetables and there appears to be practically no risk when consumed on a monthly basis. At present sea‐kale remains a desired vegetable in gastronomical dishes.