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Edible bird's nests--how do the red ones get red?
Paul Pui-Hay But1, Ren-Wang Jiang, Pang-Chui Shaw
1School of Life Sciences, The Chinese University of Hong Kong, Tai Po Road, Shatin, N.T., Hong Kong, PR China. paulbut@hotmail.com
Journal of Ethnopharmacology
|November 13, 2012
Summary
Red edible bird
Area of Science:
- Food Science
- Ethnopharmacology
Background:
- Red edible bird's nests (EBNs) are prized for perceived health benefits and higher market value compared to white EBNs.
- The origin of the red color in EBNs has been a long-standing mystery.
Purpose of the Study:
- To investigate whether white EBNs can be artificially colored red.
- To determine the role of specific environmental factors in the coloration of EBNs.
Main Methods:
- White EBNs were exposed to vapors from sodium nitrite in acidic conditions (2% HCl).
- White EBNs were exposed to vapors from "bird soil" (containing swiftlet guano) under hot and humid conditions.
Main Results:
- Exposure to sodium nitrite vapors and "bird soil" vapors successfully turned white EBNs red.
- The coloring agent in "bird soil" was found to be water-soluble and heat-stable.
Conclusions:
- The red color of EBNs is likely influenced by environmental factors within their natural habitats, such as caves and swiftlet houses.
- Chemical reactions involving environmental substances, potentially including guano, contribute to the red coloration of EBNs.
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