Antioxidants in Organic, Non-Organic Red Oranges

Background and methodology:
It is theorized that plants grown without pesticides could contain higher levels of antioxidants as a result of enhanced synthesis of active phytochemicals produced as a defense against biotic and abiotic stress. This study sought to determine whether organic red oranges (the 'Tarocco' cultivar, also known as blood oranges) have a higher phytochemical content (i.e., phenolics, anthocyanins, and ascorbic acid), total antioxidant activity, and in-vitro bioactivity than red oranges grown under integrated (non-organic) agricultural systems. Total phenolics were measured using Folin Ciocalteau assay, while total anthocyanins and ascorbic acid levels were measured by spectrophotometric and high-performance liquid chromatography analysis, respectively. Total antioxidant activity was measured by the ABTS.+  test.

Organically-grown oranges have significantly higher total levels of phenolics, total anthocyanins, and ascorbic acids than corresponding non-organic oranges. The organic orange extracts also had a higher total antioxidant activity than non-organic orange extracts. In addition, the results indicate that red oranges have a strong capacity to inhibit the production of conjugated diene containing lipids and free radicals in rat cardiomyocytes and differentiated Caco-2 cells, respectively. Statistically higher levels of antioxidant activity in both cell models were found in organically grown oranges as compared to those produced by integrated agricultural practices.

Tarozzi, A., Hrelia, S., Angeloni, C., Morroni, F., Biagi, P., Guardigli, M., Cantelli-Forti, G., & Hrelia, P. (2006). Antioxidant effectiveness of organically and non-organically grown red oranges in cell culture systems. European Journal of Nutrition45(3): 152-158. Available on-line at: