title: Metabolite profiling of edible bird's nest using gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.
abstract: BACKGROUND
  Edible bird's nest (EBN) is a renowned food item in the Chinese community due to the therapeutic effects claimed to be brought about by its consumption. However, very little scientific information has been revealed to support these claims. Thus, metabolite profiling was performed to identify the metabolites and to relate them to the medicinal properties of EBN. The study also aims to further extend the results to determine any possible differences when the EBNs are classified according to their coloration, countries or production sites.
  
  
  METHODS
  Extraction of the metabolites was performed via sonication of EBN with methanol and chloroform. Two analytical platforms, namely gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS), were utilized to detect the metabolites. This multi-analytical platform would provide a comprehensive coverage of the metabolites in EBN. GC/MS analysis was conducted in scan mode from m/z 50-650. On the other hand, LC/MS analysis was operated in both positive and negative ion mode from m/z 150-1000.
  
  
  RESULTS
  Metabolites were identified and their relationships with the medicinal properties of EBN were deduced. Classification with chemometrics illustrates that EBNs could be differentiated according to their coloration, countries and production sites. This differentiation was due to the environment where the EBNs are produced. Furthermore, GC/MS was demonstrated to be more suitable for classification as the processing methods of the EBNs did not cause a significant variation in the metabolites detected by GC/MS.
  
  
  CONCLUSIONS
  The overall findings suggest that the novel approach of metabolite profiling offers new insights to understanding EBN and provided evidence to support the medicinal properties of EBN. In addition, the success of classification of EBNs with metabolite profiling combining with chemometrics represents a paradigm shift in the quality control of this food item.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 11754, Singapore.
authors.forename: Yong Guan
authors.initials: YG
authors.lastname: Chua
authors.forename: Bosco Chen
authors.initials: BC
authors.lastname: Bloodworth
authors.forename: Lai Peng
authors.initials: LP
authors.lastname: Leong
authors.forename: Sam Fong Yau
authors.initials: SF
authors.lastname: Li
mesh_terms: D000818:Animals; D001717:Birds / Q000378:metabolism*; D002849:Chromatography, Gas; D005504:Food Analysis; D013058:Mass Spectrometry; D011786:Quality Control