Determination of the carotenoid content in selected vegetables and fruit by HPLC and photodiode array detection

Epidemiological studies have shown inverse correlations between the consumption of vegetables and fruit rich in carotenoids and the incidence of cancer and cardiovascular diseases. A total of 22 species of vegetables (including potatoes) and 28 of fruit (including rhubarb) were analysed for their contents of carotenoids by reversed-phase high-performance liquid chromatography (RP-HPLC) and photodiode array detection. A total of 27 carotenoids (among them beta-carotene, lutein and violaxanthin also as cis isomers) were identified and quantified. Lutein, beta-carotene (trans and cis forms) and violaxanthin were the predominant carotenoids in all green vegetables. Yellow and yellow-red vegetables and fruit contained beta-carotene, alpha-carotene, beta-cryptoxanthin and alpha-cryptoxanthin. Antheraxanthin and neoxanthin were found in nearly all produce. Lycopene was the predominant carotene in tomatoes, papayas and grapefruit. Vegetables with more than 10 mg of total carotenoids per 100-g edible portion were kale (34.8), red paprika (30.4), parsley (25.7), spinach (17.3), lamb's lettuce (16.0), carrots (15.9) and tomatoes (12.7). In the case of fruit, grapefruit (3.5), papayas (3.4) and nectarines (2.4) were pre-eminent with more than 2 mg of total carotenoids (except for phytoene, phytofluene and zeta-carotene) per 100 g.