Abstract:
Indigo quality is determined by its indigotin content. Another quality indicator is colour. For an evaluation of species, indigo samples from Indigofera tinctoria, Indigofera suffruticosa, Indigofera arrecta, Persicaria tinctoria, Strobilanthes cusia and Wrightia laevis cultivated in Austria and China were visually classified and analysed spectrophotometrically and using a L*a*b* measuring device. In addition to a standardised hot-extraction method without lime, some samples were extracted simulating traditional methods at ambient temperatures using lime. The highest indigotin contents were achieved with Indigofera arrecta (55%, Austria) and Strobilanthes cusia (56%, China). There were no statistically significant differences between the indigo extraction yields of the species cultivated in Austria, but Indigofera arrecta and Persicaria tinctoria had statistically significantly higher indigotin extraction yields than Indigofera tinctoria and Indigofera suffruticosa. From the species extracted in China, Strobilanthes cusia showed higher values in all parameters than Indigofera tinctoria, Indigofera suffruticosa and Wrightia laevis. Compared with the standardised method, the method simulating local practice yielded more indigo but had a lower indigotin content; the indigotin extraction yields did not differ greatly. L*a*b* values enabled precise estimations of the indigotin content, making it an interesting option for quality control, as inexpensive, easy-to-handle L*a*b* measuring instruments have become available.
摘要:
靛蓝的质量取决于其靛蓝含量。另一个质量指标是颜色。为了评估物种,靛蓝的靛蓝样本,印度,靛蓝,Persicariatinctoria,在奥地利和中国种植的Strobilanthescusia和Wrightialaevis进行了目视分类和分光光度法分析,并使用L*a*b*测量装置进行了分析。除了没有石灰的标准化热萃取方法外,在环境温度下使用石灰模拟传统方法提取了一些样品。靛蓝含量最高(55%,奥地利)和Strobilanthescusia(56%,中国)。在奥地利种植的物种的靛蓝提取率之间没有统计学上的显着差异,但是在统计学上,靛蓝和紫花的靛蓝提取率明显高于靛蓝和靛蓝。从中国提取的物种中,Strobilanthescusia在所有参数中显示出比Indigoferatinctoria更高的值,Indigoferasuffruticosa和Wrightialaevis.与标准化方法相比,模拟当地实践的方法产生了更多的靛蓝,但靛蓝含量较低;靛蓝提取率没有很大差异。L*a*b*值可以精确估计靛蓝含量,使其成为质量控制的有趣选择,作为廉价的,易于操作的L*a*b*测量仪器已经可用。