Effect of cooking processes on the contents of two bioactive carotenoids in Solanum lycopersicum tomatoes and Physalis ixocarpa and Physalis philadelphica tomatillos.

Calculation of the HPLC chromatographic retention times of different carotenoids supported our improved chromatographic separation of beta-carotene and lutein in four tomatoes and two tomatillo varieties in fresh form and after three different cooking procedures: pot boiling, cooking in a pressure cooker and microwaving. A good separation was achieved experimentally using an Ultrasphere ODS column and gradient elution with an acetonitrile-tetrahydrofuran-water mobile phase. It was shown that diverse tomato species contained different amounts of beta-carotene (6-400 microg/100 mg) and lutein (2-30 microg/100 mg). The concentration in fresh samples was higher than in cooked tomatoes. The beta-carotene content in fresh tomatillo varied between 2 and 20 microg/100 mg. Microwaving caused partial destruction of the beta-carotene and lutein in tomatillos.