Study On The Color Of β-carotene Dispersions

β-carotene is an important edible natural pigment and has strong coloring ability. It is widely used as nutrition enhancer and colorant in foods and medicines. The preparation process ofβ-carotene dispersions by milling was investigated in an aqueous medium in the presence of a hydrocolloid. Effects of factors on the color ofβ-carotene dispersions were also studied.The effects of process conditions onβ-carotene particle size and its distribution were first systematically discussed in this paper. The results show that the particle size and span decreased first, and then increased with the increase of modified starch content or milling rotational speed. The particle size and span decreased with the increase of milling time. With the increase in the amount of sodium ascorbate in dispersions,β-carotene concentration increased.The effects of factors on the color of diluteβ-carotene dispersions were first systematically researched. The results show that with either increasing the particle concentration or decreasing the mean particle size, L* value decreased, but a* and b* values and chroma increased. The hue-angle increased with decreasing the mean particle size, but did not change significantly with increasing the particle concentration. When all-trans-isomer content decreased or octyl and decyl glycerate content increased, L*, b*, chroma and hue-angle values increased, but a* value decreased.The effects of factors on the color of high concentration ofβ-carotene dispersions were also studied. The results show that the effect of the particle concentration or octyl and decyl glycerate content on the color was unremarkable. L*, b*, chroma and hue-angle values increased when the mean particle size or all-trans-isomer content decreased respectively. a* value increased with decreasing the mean particle size, but decreased with decreasing all-trans-isomer content.