Background and methodology:
Nutrients such as vitamins have been used for determining nutritional quality of many fruits and vegetables labeled as organic or conventional. The purpose of this study was to determine the nutritional value of organic and conventional broccoli, obtained at different times of the year, using vitamin C as a biomarker for nutritional quality.
Seasonal variation in the vitamin content of this vegetable also was determined. Broccoli was selected because of its typically high vitamin C content and also because this vegetable is readily available in organic and conventional varieties. The vitamin C content was measured in samples obtained from supermarkets during different seasons when broccoli could be either harvested locally or shipped far distances.
The findings indicate that vitamin C could be used as a marker under a controlled laboratory environment with some limitations and, although the vitamin C content of organically and conventionally labeled broccoli was not significantly different, significant seasonal changes have been observed. The fall values for vitamin C were almost twice as high as those for spring for both varieties. Seasonal changes in vitamin C content are larger than the differences between organically labeled and conventionally grown broccoli. This study concluded that broccoli has a complex nutrient make-up and one nutrient (vitamin C) may not represent the complete nutritional composition of this vegetable; however, it could serve as a fairly reliable index for nutritional quality.
Wunderlich, S.M., Feldman, C., Kane, S., & Hazhin. T. (2008). Nutritional quality of organic, conventional, and seasonally grown broccoli using vitamin C as a marker. International Journal of Food Sciences and Nutrition 59(1), 34-45. Available on-line at: http://dx.doi.org/10.1080/09637480701453637