Variability of phytochemical profiles in organic production: khorasan wheat case study

It raises a great deal of recent interest that organic wheat constitutes valuable nutraceutical raw material for healthy food production and special dietary uses. In particular, khorasan wheat (T. turgidum ssp. turanicum) has attracted great attention because of its specific nutritional and functional properties (antioxidant, antitumoral and prebiotic activities). Currently, few data about fibre and antioxidant composition of organically grown Kamut® brand grains is available in literature and, as far as we know, the changes of their amounts as a function of cropping year and growing location have never been investigated. Moreover, this is the first study in which an organically grown crop is investigated in a region of such broad expanse, including several different environments, covering an area of approximately 180,000 km2 . The aim of the research was to provide an overview of the health- -promoting properties of Kamut® brand grains produced at different locations (Canada and USA) and to contribute to the understanding of the environmental dynamics affecting the phytochemical profile. A collection consisting of 109 samples of organic Kamut® brand grains harvested in different farms of North America in 2010, was characterized for agronomic traits, antioxidant compounds (polyphenols, flavonoids) and fibre components (soluble and insoluble dietary fibres, resistant starch). As regards the agronomic performance, the results demonstrated a high heterogeneity among samples. Yield, test weight and protein content varied within the intervals 0.30–1.69 t/ha, 49.2–61.1 kg/hl and 12.6– –16.6 g/100 g, respectively. As previously reported in literature, the content of health-promoting compounds is strongly influenced by environmental conditions. In fact, the investigated wheat grains showed great variability for the total polyphenol and flavonoid contents (133.6–223.4 and 28.6– –63.6 mg/100g, respectively). The insoluble fibre content varied between 12.55 and 20.25 g/100 g, while the soluble dietary fraction showed less heterogeneity(2.70–4.31 g/100 g). Concerning starch, statistically significant differences were observed between farms for the amounts of both the resistant and the total starch (0.22–1.5 and 57.7–66.4 g/100 g, respectively). The results of the research were computed using Geographic Information System (GIS) to develop quality maps that showed the variability of the phytochemical amounts among the North American farms and allowed the identification of areas in which bioactive compounds had accumulated at a higher level in the wheat grains. According to the present results, the choice of a growing location in which the accumulation of health-promoting compounds (i.e. polyphenols, fibres) is stimulated by specific climatic conditions may be a key factor for the production of organic wheat foodstuff as a functional food.