Environmental and Varietal Influences on the Fatty Acid Composition of Rapeseed, Soybeans and Sunflowers

The fatty acid (FA) composition of oil crops is of some importance under technological as well as under nutritional aspects. The influence of temperature on this parameter in rapeseed, soybeans and sunflowers was investigated under practical agricultural conditions, whereby varietal variations were taken into account. The analysed plant material originated from variety testing trials located in different climatic zones of Austria. As a measure of the climatic conditions of a location, the mean temperature of the last 30 days before harvest was calculated. Despite the low temperature differences between the various locations, moderate but significant negative correlations between temperature and the share of linolenic (18 : 3), respectively, linoleic (18 : 2) acid on the whole quantity of FAs in rapeseed (R² = 0.18–0.42), soybeans (R² = 0.11–0.13) and sunflowers (R² = 0.15) were found. Furthermore, there was a good negative correlation in the case of sunflower seeds between temperature and oil level (R² = 0.45). The environmental influence on the share of polyunsaturated FAs differed between the different species. The results show that quality of vegetable oils is as well a question of environment as of variety.