HPLC ASSESMENT OF PROVITAMIN A CAROTENOIDS FROM CUCURBITA MAXIMA DUCH. EX. LAM. (MARIŢA CULTIVAR) FRUITS PUBLISHEDEdward Muntean, Ioan Rotar
Carotenoids are biologically active compounds widely distributed in plants, being responsible for the yellow to red colors of fruits and vegetables. The fruits of Cucurbita maxima Duch. - Mariţa cultivar are used as forage, being valuable sources of carbohydrates and carotenoids, especially provitamin A ones. This study emerged from the need for reliable data on the carotenoid content of feeds, knowing the demonstrated correlation between carotenoid intake (especially of those with provitamin A activity) and health. Meanwhile, knowing the carotenoid levels is an important task for this fruits being used rationally in animal feeding. In this study, carotenoids were completely extracted from ripe fruits of Cucurbita maxima Duch. - Mariţa cultivar using methanol and acetone. After saponification, high performance liquid chromatography was conducted on a Nucleosil 120-5 C 18 column, using a gradient with two mobile phases: a mixture of acetonitrile:water and ethyl acetate. Detection was accomplished using a Waters 990 photodiode array detector. Carotenoid identification was completed based on HPLC co - chromatography with available standards and by comparison of the visible absorption spectra with those of reference carotenoids, while quantification was achieved using the external standard method. The average concentrations of the carotenoids from the fruit’s mesocarp, expressed in g/g dry weight, are: lutein - 50.72, violaxanthin - 25.79, - carotene - 15.36, neoxanthin - 5.36, flavoxanthin - 4.31 and lutein 5, 6 - epoxide - 2.1. Cucurbitaxanthin A, lactucaxanthin, zeaxanthin, -cryptoxanthin, -cryptoxanthin, -carotene 5, 6 - epoxide, -carotene and 15, 15’ - cis - - carotene were also detected, but were under the quantification level. The fruit’s epicarp showed a similar HPLC chromatographic pattern, but with different carotenoids concentrations g/g dry weight): lutein - 54.21, violaxanthin - 17.11, - carotene - 9.47, flavoxanthin - 5.31, lactucaxanthin - 3.48, neoxanthin - 2.35, cucurbitaxanthin A - 1.61, zeaxanthin - 1.45 and lutein 5, 6 - epoxide - 1.25. -cryptoxanthin, -cryptoxanthin-carotene, 15, 15’- cis -- carotene and auroxanthin were detected under the quantification level.
carotenoids; provitamins A; chromatography; HPLC; feed; Cucurbita maxima Duch. ex.Lam. - Mariţa cultivar