Thermal effects on losses of carotenoid contents, especially on violaxanthin, antheraxanthin, and cis-violaxanthin, were clearly detected. Isomerizations of the main 5,6-epoxide carotenoids to 5,8-epoxides are probably responsible for the color changes after thermal juice pasteurization. There was perceptible color change during orange juice pasteurization, which led to juice color becoming lighter and more saturated.