Nutritional quality of organic and conventional wheat

Abstract

The popularity of organic food and the farming area managed according to organic agriculture practices have been increasing during the last years. It is not clear, whether foods from organic and conventional agriculture are equal with respect to nutritional quality. We chose wheat (Triticum aestivum L., cv. Titlis) as one of the most important crop plants to determine a range of substances relevant for human nutrition in crops from organic and conventional agriculture systems. Wheat grains of 2003 originating from a long term field experiment, the Swiss DOK trial, consisting of bio-dynamic, bio-organic and conventional farming systems were used. Thousand seed weight, protein content, phosphate levels, antioxidative capacity, levels of phenols, fibre, fructan, oxalate and phytic acid were determined in whole wheat meal from the various organic and conventional growing systems of the DOK trial. Levels of these substances fell into a range that is known to occur in other wheat crops, indicating that wheat from the DOK trial was not special. Clearcut differences were observed for none-fertilised wheat, which was significantly lowest in thousand seed weight, protein and significantly highest in total oxalate. For the majority of the nutritionally important substances analysed, there were no significant differences between bio-dynamic, bio-organic, and conventional growing systems. Only protein content and levels of fibres were statistically different. Taken together, the magnitude of observed variations was very small. The results of our investigations do not provide evidence that wheat of one or the other agriculture system would be better or worse.