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International Journal of Analytical Chemistry
Volume 2015, Article ID 748056, 5 pages
Research Article

Development of a Rapid and Simple Method for Detection of Protein Contaminants in Carmine

1Graduate School of Environmental Symbiotic System and Department of Innovative Systems Engineering, Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro-machi, Saitama 345-8501, Japan
2Kishi Kasei Company, 1-10-8 Fukuura, Kanazawa-ku, Yokohama 234-0004, Japan

Received 1 December 2014; Revised 16 March 2015; Accepted 19 March 2015

Academic Editor: Shaoping Li

Copyright © 2015 Norihisa Nakayama et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Protein contaminants in carmine can cause dyspnea and anaphylactic reactions in users and consumers of products containing this pigment. The method generally used for detection of proteins in carmine has low reproducibility and is time-consuming. In this study, a rapid, simple, and highly reproducible method was developed for the detection of protein contaminants in carmine. This method incorporates acidic protein denaturation conditions and ultrafiltration. To prevent protein aggregation, sodium dodecyl sulfate containing gel electrophoresis running buffer was used for dispersing the carmine before filtration. An ultrafiltration device was used to separate the protein contaminants from carminic acid in the carmine solution. Two ultrafiltration devices were compared, and a cylindrical device containing a modified polyethersulfone membrane gave the best results. The method had high reproducibility.