Samples (174) of cabbage, Brussels sprouts, cauliflower and swede-turnip have been analysed for total and individual glucosinolate content in both the fresh and cooked form. Using data from the 1980 National Food Survey, the national mean daily intake is calculated to be 46.1 mg in fresh material, and 29.4 mg in cooked. There are large variations within the UK (for example in Scotland it is less than half that in south-west of England), between income groups and over the year. National mean daily intake figures for the glucosinolates yielding goitrogenic products such as oxazolidine-2-thiones and thiocyanate ion are 6.7 and 14.7 mg respectively; the former figure is approximately doubled in the winter months. Based upon the above variations, arising from eating habits in the UK, together with the known large variation in glucosinolate content in cruciferous plants because of agronomic and environmental effects, it is likely that certain individuals will consume more than 300 mg total glucosinolates per day. The nutritional and toxicological consequences of such an intake are unknown at present.

An hplc method of glucosinolate analysis is described which allows the quantitative determination of these compounds in cruciferous oilseeds, vegetables and forage crops. The method compares favourably with a gas chromatographic technique for individual glucosinolate analysis and has several advantages which are particularly useful for the analysis of seed and leaf material. Whilst no attempt has been made to optimise the analytical procedures to allow the rapid screening of breeding programmes, this would not appear to be limiting.

The glucosinolate content of 27 cultivars of commercially grown cauliflower have been determined. The levels of total glucosinolates (<120mg 1OOg-' fresh wt) were comparable with those previously reported for cabbage, but much lower than those found in Brussels sprouts. The major individual glucosinolates were identified as those possessing prop-2-enyl-, 3-methylsulphinylpropyl-, 3-indolylmethyl-and l-methoxy-3-indolylmethyl-side chains. Smaller amounts of but-3-enyl-, 2-hydroxybut-3-enyl-, 3-methylthiopropyl-, 4-methylthiobutyl-, 2-phenylethyl-, pent-4-enyl-, 2-hydroxypent-Cenyl-and 5-methylthiopentyl-glucosinolates were also measured in some cultivars, the last three compounds not previously having been reported in cauliflower. Environmental effects, determined for the cultivars Wallaby, Coolabah, Barrier Reef and Snowy River were much less than previously found in Brussels sprouts.

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