DEVELOPMENT AND EVALUATION OF AN HPLC METHOD FOR THE ANALYSIS OF CAROTENOIDS IN FOODS, AND THE MEASUREMENT OF THE CAROTENOID CONTENT OF VEGETABLES AND FRUITS COMMONLY CONSUMED IN THE UK

This study further examines the factors which affect the chromatograph ic response of carotenoids and contribute to analytical variation and inaccuracies in their quantitative determination. A method for the ana lysis of carotenoids in vegetables and fruits is described and data ar e presented for the carotenoid content of vegetables and fruits common ly consumed in the UK. The addition of a solvent modifier (triethylami ne) to the mobile phase was shown to improve the recovery of carotenoi ds from the column from around 60% to over 90%. The linearity and repr oducibility of the chromatographic response was investigated and the r obustness and reproducibility of the method nias measured using a refe rence vegetable material developed in the laboratory. Short and longer term reproducibility showed an average CV of around 8% for all carote noids. Analysis showed that good sources (>1000 mu g/100 g) of lutein were: broccoli, butterhead lettuce, parsley, peas, peppers, spinach an d watercress; of lycopene: tomatoes and tomato products; and of beta-c arotene: broccoli, carron, greens, butterhead lettuce, mixed vegetable s, parsley, spinach and watercress. There was little or no loss of car otenoids on cooking, green vegetables showed an average increase in lu tein levels of 24% and in beta-carotene levels of 38%. This study and previous studies in our laboratory have demonstrated that a number of factors affect the validity of the 'peak response' and are likely to c ontribute to within and between laboratory variation. It is suggested that the development and use of standard reference materials would sig nificantly improve the quality of data.