Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, 132# Lanhei Road, Kunming, 650201, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
J Ethnobiol Ethnomed. 2021 Apr 7;17(1):25. doi: 10.1186/s13002-021-00454-z.
As one of the oldest traditional dyes, people worldwide have used natural indigo for centuries. Local people have unique knowledge about indigo identification, which is crucial for indigo quality control and determining the dyeing effects. However, such traditional knowledge is rarely documented and explained. Therefore, the aims of this study were to document and assess the traditional knowledge used by local people when identifying natural indigo paste as well as quantitatively explore the characteristics and material basis of such traditional knowledge.
Three field surveys were conducted between 2019 and 2020. A total of 283 traditional indigo-paste artisans were interviewed in Guizhou, Yunnan, and Fujian Provinces. The frequency of citation, mention index, and fidelity level of each indigo-paste quality criterion were calculated to determine the most commonly used, recognized, and important quality criteria. To explore the characteristics and material basis of the traditional knowledge, we analyzed 21 indigo-paste samples using high-performance liquid chromatography with diode-array detection (HPLC-DAD), pH, and particle size analyses.
Local people possess unique knowledge to identify natural indigo. Based on this knowledge accumulated over thousands of years, four criteria (color, taste, touch, and dyeing ability) were chosen by local people, and using these criteria, nature indigo was divided into five quality grades. The best quality indigo paste was judged according to the following folk criteria: dark blue in color with a purple-red luster; smooth and difficult to wipe off; having a sweet, bitter or spicy taste; and easy cloth dyeing. Additionally, the higher the contents of indigo and indirubin-especially indirubin-the better is the quality of the indigo paste. Within the pH range of 9-12, high-quality indigo-paste was more acidic. There was no significant relationship between particle size and quality.
The ancient methods used by local people for identifying natural indigo are comprehensive and unique. By documenting the various folk quality criteria and conducting quantitative analyses, this study revealed the importance of indirubin and pH for assessing the quality of indigo paste. These findings differ from existing quality standards for synthetic indigo. Amid rapid modernization, traditional knowledge remains invaluable as a world heritage of humanity that warrants preservation.
天然靛蓝作为最古老的传统染料之一，已被世界各地的人们使用了数个世纪。当地人对靛蓝的鉴定具有独特的知识，这对于靛蓝质量控制和确定染色效果至关重要。然而，这种传统知识很少被记录和解释。因此，本研究的目的是记录和评估当地人在鉴定天然靛蓝糊时使用的传统知识，并定量探索这种传统知识的特征和物质基础。
本研究于 2019 年至 2020 年期间进行了三次实地调查。在贵州、云南和福建三省共采访了 283 位传统靛蓝糊工匠。计算每种靛蓝糊质量标准的引用频率、提及指数和保真度水平，以确定最常用、最公认和最重要的质量标准。为了探索传统知识的特征和物质基础，我们使用高效液相色谱法与二极管阵列检测（HPLC-DAD）、pH 值和粒径分析对 21 个靛蓝糊样品进行了分析。
当地人拥有独特的知识来识别天然靛蓝。基于数千年来积累的知识，当地人选择了四个标准（颜色、味道、触感和染色能力），并使用这些标准将天然靛蓝分为五个质量等级。质量最好的靛蓝糊是根据以下民间标准判断的：颜色深蓝带紫红色光泽；光滑且不易擦拭；具有甜、苦或辣的味道；易于对布料进行染色。此外，靛蓝和靛玉红（尤其是靛玉红）的含量越高，靛蓝糊的质量越好。在 pH 值 9-12 的范围内，高质量的靛蓝糊更偏酸性。粒径与质量之间没有显著关系。
当地人用于识别天然靛蓝的古老方法是全面而独特的。通过记录各种民间质量标准并进行定量分析，本研究揭示了靛玉红和 pH 值对评估靛蓝糊质量的重要性。这些发现与现有的合成靛蓝质量标准不同。在快速现代化的背景下，传统知识仍然是人类宝贵的世界遗产，值得保存。
