title: Influence of storage duration and processing on chromatic attributes and flavonoid content of moxa floss.
abstract: OBJECTIVE
  Moxibustion is an important traditional Chinese medicine therapy using heat from ignited moxa floss for disease treatment. The purpose of the present study is to establish a reproducible method to assess the color of moxa floss, discriminate the samples based on chromatic coordinates and explore the relationship between chromatic coordinates and total flavonoid content (TFC).
  
  
  METHODS
  Moxa floss samples of different storage years and production ratios were obtained from a moxa production factory in Henan Province, China. Chromatic coordinates (L*, a* and b*) were analyzed with an ultraviolet-visible spectrophotometer and the chroma (C*) and hue angle (h°) values were calculated. TFC was determined by a colorimetric method. Data were analyzed with correlation, principal component analysis (PCA).
  
  
  RESULTS
  Significant differences in the chromatic values and TFC were observed among samples of different storage years and production ratios. Samples of higher production ratio displayed higher chromatic characteristics and lower TFC. Samples of longer storage years contained higher TFC. Preliminary separation of moxa floss production ratio was obtained by means of color feature maps developed using L*-a* or L*-b* as coordinates. PCA allowed the separation of the samples from their storage years and production ratios based on their chromatic characteristics and TFC.
  
  
  CONCLUSIONS
  The use of a colorimetric technique and CIELAB coordinates coupled with chemometrics can be practical and objective for discriminating moxa floss of different storage years and production ratios. The development of color feature maps could be used as a model for classifying the color grading of moxa floss.
authors.affiliation: School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing 100029, China.
authors.forename: Min Yee
authors.initials: MY
authors.lastname: Lim
authors.affiliation: School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing 100029, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.affiliation: School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing 100029, China.
authors.forename: Bai-xiao
authors.initials: BX
authors.lastname: Zhao
authors.affiliation: Library, Beijing University of Chinese Medicine, Beijing 100029, China.
authors.forename: Hui-qin
authors.initials: HQ
authors.lastname: Zou
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Yong-hong
authors.initials: YH
authors.lastname: Yan
mesh_terms: D003116:Color; D005419:Flavonoids / Q000032:analysis*; D009071:Moxibustion
chemical_list: D005419:Flavonoids