The effect of temperature on sensory quality, chemical composition and growth of carrots (Daucus carota L.) I.: Constant diurnal temperature

The carrot cv. Panther F-1 grown in phytotrons at 9, 12 15, 18 and 21 degrees C constant diurnal temperatures at two locations, Angstrom, (59 degrees 40'N) and Tromso (69 degrees 39'N), and harvested at two dates was evaluated for sensory attributes, chemical composition and morphological variates. Significant temperature effects were detected for most sensory, chemical and physical variables. High growing temperatures (18 and 21 degrees C) favoured colour, bitter tasting flavour components, firmness and the dry matter, sucrose and carotene content of the roots, whereas low growing temperature (9 and 12 degrees C) heightened sweet taste, acidic taste, crispness, juiciness, and the fructose and glucose content. The longest roots were obtained at 9 and 12 degrees C, the highest root weights at 12 and 15 degrees C. Principal component analysis (PCA) revealed clear differences in the sensory profile of carrots grown at high and low temperatures, expressed by the first three principal components which together explained 81% of the variation in sensory variables. PCA of chemical and physical variables explained 90% of the variation, variables to describe the variation in PC1 were root diameters, p-carotene and sucrose, while root length, dry matter and fructose contributed to describe the variation in PC2.