Abstract
Gardenia yellow pigment, which contains seven crocetin derivatives, is widely used to many process foods as food colorant. In this paper, the food chemical properties of the individual crocetin derivatives were examined on color tone, antioxidative activity, heat and light stability. The results obtained could be summarized as follows: (1) There was little difference in the chroma and brightness among the seven crocetin derivatives. In color tone (hue), however, there was clear difference depending on the number of glucose unit linked to crocetin. Thus the hue value decreased according to the increase in the number of glucose unit linked to crocetin, indicating that the color tone changes to reddish from yellowish tone. (2) All of crocetin derivatives inhibited oxidation of linoleic acid about 80%. This result showed that Gardenia yellow pigment was useful to prevent the oxidation of the process foods. (3) All of crocetin derivatives were stable for heat and residual ratio of pigment was more than 85% after the heat treatment of 80°C, 120 minutes. (4) All of crocetin derivatives were appreciably stable to irradiation of light with wavelengths in the range from 400nm to 700nm, but were extremely unstable to ultraviolet rays irradiation in the region from 250 to 390nm. Further, the stability of irradiation of crocctin derivatives which linked gentiobiose to crocetin were superior to others.
