新疆野生核桃叶和外果皮中色素含量研究

以新疆伊犁地区野生核桃（Juglans fallax）叶和外果皮为试材,研究了其中提取液的吸收光谱和低温冷冻对色素提取的影响。结果表明核桃叶中的叶绿素在冷藏后明显下降,而核桃外果皮中的叶绿素变化不明显。提取液的吸收光谱基本相似,用Lichtenthaler计算公式进行叶绿素含量测定。叶中叶绿素a在冷藏后吸光值明显减小,叶绿素b吸光值减小不明显,但类胡萝卜素却增加了,而野生核桃外果皮中的叶绿素a,b冷藏前后变化不明显,只有类胡萝卜素有明显增加。新鲜野生核桃色素提取液呈淡绿色,冷藏后两者的提取液颜色呈褐色,随时间增加颜色变深。冷藏处理后野生核桃叶色素含量在220nm～420nm波段有吸收峰,提取液放置40小时内吸光值相似,标准偏差0.043,稳定性良好;野生核桃外果皮色素含量在220nm～410nm及420nm～580nm波段有吸收峰,提取液4小时后吸光值相似,标准偏差0.028,稳定性良好,在420nm～580nm之间,0小时的提取液吸光值急剧减少,小于4小时之后提取液的吸光值。野生核桃的核桃醌易溶于丙酮,影响植物提取液的吸光值。叶中的核桃醌的吸光值随时间的增加而增加;外果皮中的核桃醌的吸光值随时间的增加先减少后增加;颜色稳定,均可用于褐色色素提取。

Study on Xinjiang Wild Walnut Leaves and Epicarp Pigment Content

Taking leaves and epicarp of wild walnut(J.fdlax Dode) as materials,the absorption spectrometry and the impact of subzero refrigeration on the extraction were studied.The results showed that the absorption of leaves chlorophyll reduced significantly,and the absorption of leaves chlorophyll b decreased unconspicuously,but the absorption of carotenoid increased after subzero refrigeration.The absorption of epicarp’s chlorophyll a and chlorophyll b did not change significantly,and the absorption of carotenoid significantly increased.Frozen wild walnut leaves extraction has one absorption peak at 220nm～420nm,stabilized for 40 hours that standard deviation of absorption is 0.043.Meanwhile,the wild walnut epicarp extraction have two absorption peak at 220nm～410nm and 420nm～580nm,stabilized for 4 hours that standard deviation of absorption is 0.028.The absorb spectra value of 0-hours wild walnut epicarp extraction dropped sharply at 420nm～580nm and is less than the value of 4-hours.The wild walnut quinone dissolved in acetone and increased the absorption spectra value of the leaves extraction over time,the absorption spectra value of epicarp extraction first decreased and then increased.The extraction color is steady and can be used to extract brown pigment.