Impact of Thermal and Pressure-Based Technologies on Carotenoid Retention and Quality Attributes in Tomato Juice

The aim of this study was to investigate the impact of thermal processing (TP) (90 A degrees C, 90 s), high-pressure processing (HPP) (600 MPa, 46 A degrees C, 5 min), and high-pressure homogenization (HPH) (246 MPa, 99 A degrees C, < 1 s) on product quality parameters, specifically carotenoid content, and physicochemical attributes of particle size, color, viscosity, total soluble solids, and pH in tomato juice. Unprocessed tomato juice was used as control. The four major species of carotenoids (lycopene, beta-carotene, phytoene, and phytofluene) in tomato juice were analyzed by HPLC. The content of total lycopene, all-trans-lycopene, cis-lycopene isomers, phytoene, and phytofluene, in TP-, HPP-, and HPH-treated tomato juice did not significantly differ from that in unprocessed (control) juice. Significant reduction in beta-carotene content was observed after TP treatment but not after HPP and HPH treatments. HPH significantly reduced tomato juice particle volume mean diameter from similar to 330 mu m in control, HPP-, and TP-treated tomato juices to similar to 17 mu m. A concomitant increase in apparent viscosity was observed in HPH-treated juice versus control. HPH-treated juice had increased redness (a*) and yellowness (b*) than that in control and HPP-treated tomato juices. These results indicate that high-pressure-based technologies (HPP and HPH) can preserve carotenoids as well as improve physicochemical properties.