Organic and conventional strawberries: nutritional quality, antioxidant characteristics and pesticide residues

Introduction - Organic farming system may affect the food composition and produce healthy foods. The aim of this study was to compare the nutritional quality, antioxidant properties and pesticide residues of organic or conventional strawberries. Materials and methods - In a first experiment, organic and conventional fruits from the cvs. Camarosa and Albion were obtained directly from the farmers. Subsequently, 'Camarosa' was produced in organic and conventional systems, under controlled conditions. Pesticide residues were analysed in the second trial and the remaining parameters were evaluated in both experiments. Results and discussion - In the first experiment, the fruits of organic cv. Albion showed higher moisture (91.8%) and lower total solid (8.2%), and carbohydrate (5.7%) contents. 'Albion' fruits also showed higher total solid content than 'Camarosa' fruits in conventional farming system. Pesticide residues were not detected. Under controlled conditions, organic 'Camarosa' fruits had higher moisture (91.5%) and ash (0.4%) contents, whereas conventional strawberries had higher soluble solids (8.5 degrees Brix), proteins (0.9%) and anthocyanins (17.7 mg 100 g(-1)). Residues of azoxystrobin, lambda-cyhalothrin and thiamethoxam were detected at values below the limit of detection (< LOD) in all organic samples, and below the limit of quantification (< LOQ) in conventional strawberries. Conclusion - Organic and conventional production systems do not promote any expressive difference in the nutritional quality or antioxidant properties of strawberries, although the organic farming produced pesticide-free fruits.