栀子紫色素制备及其稳定性研究

Study on preparation and stability of gardenia purple pigment

利用纤维素酶水解京尼平苷后与氨基酸反应制备栀子紫色素。研究了栀子紫色素的光稳定性、热稳定性、pH稳定性和耐氧化还原性,并就食品中常见的金属离子和食品添加剂对栀子紫色素稳定性的影响进行探讨。结果表明:光照对栀子紫色素影响较小,在光照中,栀子紫色素呈微弱褪色趋势;栀子紫色素在80℃内比较稳定,随着时间的延长色素吸光度值呈微弱下降趋势,而在100℃中有较大褪色趋势;pH对栀子紫色素影响较大,在pH为6.0时吸光度值最高,因此栀子紫色素最好保存于弱酸性环境中;其抗氧化性较差,但对还原剂的耐受性良好;栀子紫色素不受大多数金属离子的影响,而在Zn2+、Fe2+、Fe3+与Cu2+环境中容易形成沉淀。大部分食品添加剂对栀子紫色素稳定性影响不大。栀子紫色素具有良好的理化性质,为栀子紫色素的生产应用提供了参考数据。

After geniposide hydrolyzed by cellulose enzyme, it reacted with amino acids to synthesis gardenia purple pigment. The chemical properties of the pigment including photostabihty, thermo stabihty, pH stability and resistance to oxidant - reduction were examined. The major cations and food additives influence on the pigment stability were also studied. The results show that light has little effect on gardenia purple pigment, it only turned lighter in the light. It is stable below 80 ℃, the pigment absorbance values show a downward trend with the prolonging of time, while at 100 ℃ it decreased dramatically. The value of pH has great influence on the pigment, the absorbance value of the pigment solution goes the highest when the solution is at pH 6. This shows that the pigment is better preserved in weak acidic envi- ronment. Gardenia purple pigment was very sensitive to oxidation, but it was stable to the reducing agents. Most of the metal ions have low effects on the pigment, but it is easy to form a precipitate while in the Zn^2＋ , Fe^2＋ , Fe^3＋ and Cu^2 ＋ environment. Most food additives have little effects on gardenia purple pigment. Gardenia purple pigment has excellent physicochemical properties and the research provides the reference for the production and application of Gardenia purple pigment in the future.