Storage stability of strawberry jam color enhanced with black carrot juice concentrate

Black carrot juice concentrate was added to enhance the color of strawberry jams prepared from two locally grown cultivars, Osmanli and Kara. Compared to other cultivars processed to jams, these two cultivars are lightly colored but very aromatic. Color and pigment stability of colored and noncolored (control) strawberry jams were studied during storage. The use of black carrot concentrate as a source of natural colorant stabilized the color of strawberry jam. The stabilization was more noticeable for jams prepared from Osmanli cultivar. Monomeric anthocyanin degradation was fitted to a first-order reaction model. Storage temperature had a strong influence on anthocyanin degradation. As the storage temperature increased, the stability of anthocyanins decreased significantly in both colored and noncolored jams. Parallel to decrease in monomeric anthocyanins, hue (h degrees) values of all jam samples increased throughout the storage. However, increase in h degrees values was much smaller in colored samples than in noncolored samples. High correlation was found between h degrees value and anthocyanin concentration at 22C (r = 0.910-0.978) and 37C (r = 0.931-0.981).