The extraction of brown pigment from hazelnut shells and its stability.

The conditions for extracting a natural brown pigment were studied.The physicochemical properties of the pigmen were tested.The pigment was obtained from hazelnut shells with ethanol as extractant and the stability of the pigment was test-ed.The optimum conditions for solvent extracting were: at 80℃,extracting time 80min,60%(volume percent) ethanol as extrac-tant.The results of physicochemical tests showed that the pigment was a kind of water dissolvable pigment with heat stability.The stability of the pigment could be influenced in high density lighting.The pigment was stable under pH=4～12.Na+,K+,Ca2+,Al3+ and Mg2+ had little effects on pigmen stability.However,Fe3+,Cu2+ and Zn2+ had severe effects on pigmen stability.The pig-ment had better endurance capability against some common food additives,but its colour was decreased slightly by citric acid.The extracting technique of brown pigment is uncomplicated.