Background and methodology:
There is scientific evidence that organically grown crops contain higher mineral, vitamin and antioxidant content and have better flavor than crops produced using conventional systems. However, there is still a debate over the perceived quality advantage of organically grown fruits and vegetables. This study focused on commercial production of tomatoes used for processing. The objective of this study was to compare the quality and nutritional value of processing tomatoes grown on matched commercial grower fields in California. Samples were taken from the tomatoes grown on 4 pairs of matched fields. Each field pair consisted of matched organic and conventional fields. At harvest, 4.54 kilograms of red ripe fruit were hand-harvested from each of the eight research plots in each field and delivered the same day to the University of California-Davis Food Science and Technology laboratory for analysis of fruit quality components.
For the four growers studied, individual analysis of variance results indicated that tomato juice prepared from organically grown tomatoes on some farms was significantly higher in soluble solids, higher in consistency, and titratable acidity, but lower in red color, ascorbic acid and total phenolics content in the microwaved juice. Results were significantly different among specific growers, and this may be attributed to differences in soil type and soil nutrients, tomato cultivar, environmental conditions, or other production-related factors. Higher levels of soluble solids, titratable acidity, and consistency are desirable for the production of tomato paste, in that tomatoes with these attributes may be more flavorful and require less thermal treatment. This has the potential to result both in cost savings from less energy required in paste manufacture and potentially a higher quality product due to less thermal degradation of color, flavor and nutrients.
Barrett, D. M., Weakley, C., Diaz, J.V. & Watnik, M. (2007).Qualitative and nutritional differences in processing tomatoes grown under commercial organic and conventional production systems.Journal of Food Science, 72(9), C441-C451.