天然色素的复配调色及稳定性研究

Study on the Compound Toning of Natural Pigments and Their Stability

以红曲红、栀子蓝、姜黄素3种天然色素为原料,按不同体积比进行两两复配调色,用精密色差仪和目测比色法评价复配颜色,并以色差(ΔE)为评价指标,考察温度、pH、光照和金属离子对天然复配色素稳定性的影响。结果表明,栀子蓝与姜黄素复配调色可得豆绿、豆蔻绿和稚蓝,红曲红与姜黄素复配调色可得到柠黄、桔黄和桔红,红曲红与栀子蓝复配调色可得到紫色、粉红和桔红。随着温度升高,复配色素的稳定性均下降,其中,红曲红与栀子蓝复配所得的紫色、粉红和桔红受温度影响损失最小。复配色素溶液在强碱条件下稳定性急剧下降。避光可以显著降低复配色素的损失率。金属离子Fe^(3+)、Cu^(2+)对复配色素稳定性的影响显著高于Mg^(2+)、Na^(+)、Ca^(2+),红曲红与栀子蓝复配所得的桔红色素受金属离子影响损失最小。

Three natural pigments of monascus red,gardenia blue and curcumin were used as raw materials to tone new color,and the compound color was evaluated by a precision colorimeter and visual colorimetry.The color difference(ΔE)was used as the evaluation index to indicate the effects of temperature,pH,light and metal ions on the stability of those compound pigments.The results showed that bean green,cardamom green and naive blue could be obtained by mixing gardenia blue and curcumin;Lemon yellow,orange yellow and orange red could be obtained by mixing monascus red and curcumin;Purple,pink and orange red could be obtained by mixing monascus red and gardenia blue.With the increase of temperature,the stability of the compound pigments decreased.The stability of purple,pink and orange red obtained by mixing monascus red and gardenia blue were better than others under the relatively higher temperature.And their stability decreased remarkably under strong alkali conditions.Keeping in dark could improve their stability than in light place.The influence of metal ions Fe^(3+)and Cu^(2+) on the stability of the compound pigment was significantly higher than that of Mg^(2+),Na^(+) and Ca^(2+).Metal ions had negligible impact on the orange red compound pigments.