Tomatoes are an exceptionally rich source of lycopene, which has been reported to have beneficial antioxidant effects and may be a major factor in reducing the development of cancer and heart disease. Tomato breeders, growers and processors are therefore interested in the lycopene composition of different tomato varieties, and how composition is affected by growing region and season. Over 550 replicated and observational tomato variety samples were grown by Farm Advisers in Colusa, Fresno, Merced, San Joaquin, Stanislaus, Sutter and Yolo counties of California. Lycopene content was determined on tomato juice which had been exposed to a microwave hot break which simulates commercial hot break procedures. Lycopene content varied by county, with higher values in Stanislaus and Yolo during the early season and in Fresno, San Joaquin and Colusa in the mid season. Normalized values for lycopene content ranged from 84.1 to 172.9 mg/kg, or a 100% difference from lowest to highest. Some varieties stood out with particularly high values in most counties. Correlations between lycopene content and color (a*, a*/b*, chroma and L*) were investigated.
