Background and methodology
Little information exists on how organic production methods affect nutrient content of tomatoes. This project was undertaken to determine how much lycopene (natural pigments found in red fruit such as tomatoes and watermelon that act as antioxidants) was produced in tomatoes grown organically and if tomatoes picked at the breaker stage could obtain full lycopene content. Thirteen tomato cultivars (12 beefsteak and one Roma type) were grown in certified organic fields at Lane, Oklahoma, and fertilized only with organic poultry litter. Pesticides approved for organic use were applied as necessary. Fruit was randomly harvested across plots at the breaker, turning, pink, light red, firm red, and soft red stages of fruit color. Tomatoes were selected to be free of defects due to insects, disease or cracks. For ripening studies, tomatoes were placed at random on metal trays at 75–80% relative humidity and held until soft red; this was done under fluorescent and indirect lighting.
‘Classica,’ a Roma type of tomato, was highest in lycopene, and the other cultivars had lycopene in soft red fruit. Tomatoes grown organically contained substantial amounts of lycopene when ripened to firm red or soft red stages. About half of the total lycopene found in soft red tomatoes was present in pink tomatoes and 70 percent in light-red fruit. Fruit picked at unripe stages (breaker through light red) gained as much or more lycopene as those picked at the firm or soft red stages. Results indicated that fruit could be harvested well before full visible red color without loss of lycopene.
Perkins-Veazie, P., Roberts, W., & Collins, J. K. (2006). Lycopene content among organically produced tomatoes. Journal of Vegetable Science, 12(4), 93-106. Available on-line at: http://dx.doi.org/10.1300/J484v12n04_07