Effect of organic and conventional agronomic practices and variety of choice on nutritional quality, the contents of undesirable compounds and yield of cereals

PhD Thesis ; Cereal products are one of the most important sources of nutrients and energy in the human diet, and common wheat is the most consumed crop globally. Spelt wheat -one of the most ancient cereals- is increasing its share in the food markets because of its ability to grow under low inputs and consumers’ belief about its high quality. The demand for spelt wheat and other minor cereals is particularly high in the organic food market, much of which is driven by consumers’ expectations that organic farming practices could improve the content of beneficial nutrients and decrease the content of undesirable compounds such as pesticides. The aim of this thesis was to explore the effect of organic and conventional agronomic practices (fertilisation and irrigation) and variety choice on the nutritional quality and undesirable compounds (heavy metals, mycotoxins and pesticides) of grain/flour of different cereal species (mainly common wheat and spelt wheat). The objectives were to carry out (1) a meta-analysis of data on effects of organic and conventional agronomic practices on mycotoxin contamination in cereals and (2) a shopping basket study to collect flour from supermarkets in the UK and Germany over three years; and (3) to carry out a field experiment, where various spelt wheat genotypes were cultivated under different fertility treatment and irrigation regimes. The contents of nutritionally relevant compounds such as phenolic acids, flavonoids, protein, and macro- and micronutrients, as well as undesirable compounds such as heavy metals were measured in the shopping basket and field study. In addition, mycotoxins and pesticide residues were measured in the shopping basket study. The meta-analysis of mycotoxin content of cereal grains was based on 79 published studies and found that, historically, conventional cereals had consistently higher levels of Fusarium mycotoxin contamination and organic cereals had higher levels of OTA contamination. However, the contamination and prevalence of OTA in organic ...