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  5. New Japan-Oriented ISO Standards Issued for Test Methods Applying Protein Analysis Technologies

New Japan-Oriented ISO Standards Issued for Test Methods Applying Protein Analysis Technologies

ISO standards for a test method contributing to fair trade of cashmere products

November 8, 2018

New international standards for a method for proteomic analysis of cashmere and some other animal hair fibers issued as “ISO 20418-2: Textiles -- Qualitative and quantitative proteomic analysis of some animal hair fibers -- Part 2: Peptide detection using MALDI-TOF MS,” based on the proposal filed by Japan to the International Organization for Standardization (ISO)* and the approval of the proposal by the ISO. This method utilizes the structural differences of protein in hairs by a species of animals, correctly identifies cashmere or other animal fibers and measures the blend ratios of such fibers. These standards are expected to prevent false cashmere fibers and promote fair trade worldwide.

*Note: Japan is a secretariat of the ISO Technical Committee 38: Textiles, the committee that examined Japan’s proposal for the standards.

1. Background

Cashmere is popular, high-end fibers and often used for sweaters and coats. Yet identification of species of animal hairs and correct analysis of composition of animal hair fibers are difficult tasks. In particular, in cases that such fibers look very similar, for e.g., cashmere fiber and yak fiber, or when the surfaces of fibers are damaged by repeated processing, it is often difficult to identify the true source species of the fibers. Although experts with quality skills and experiences are committed to identification of cashmere using microscopes, disguised cashmere fibers, such as fibers replaced by or blended with wool, are often traded by people who take advantage of loopholes in analyzing technology.

To address this situation, development of objective methods for testing cashmere fibers in addition to the existing test using microscopes has been an urgent challenge to overcome in order to provide secure quality cashmere for consumers.

2. Outline of the international standards

Approximately 90% of animal hairs in weight consist of multiple types of protein called keratin. This keratin varies depending on the species of animal but looks very similar. The newly established method allows experts to identify such species by amino-acid sequences that are slightly different between animals.

In this identification process, experts pulverize animal hairs, react them with substances called reducing agents, and heat and dissolve them into solutions, and then they adopt an electrophoresis method so as to pick up keratin I, the target of analysis, out of the solutions. Following this, experts react the keratin I with an enzyme called trypsin, change the keratin into short peptides and analyze the peptides using the MALDI-TOF MS analysis method to find animal-species-specific peaks. Finally, they identify the species of animal from the position from which the peaks emerge (see the horizontal axis of Figure 2) and uncover the blend ratios of animal hairs from the height of the peaks (see the vertical axis of Figure 2).

Figure 1: Outline of the test method

Figure 2: Example of analysis results of the MALDI-TOF MS analysis method

3. Expected effects

This method allows experts to scientifically and efficiently analyze firmly-dyed products and damaged fibers. It also helps experts to access information on all animal species which compose the target fibers and to analyze even a single hair. Due to this efficiency, this method can be applied to inspections of foreign substance entering foods.

Worldwide popularization of this method under the ISO standards is expected to contribute to enhancing the accuracy of identifying cashmere fibers, preventing distribution of disguised cashmere products in global markets, promoting fair trade and providing more secure quality cashmere for consumers.

ISO code Name of standard Outline
ISO 20418-2 Qualitative and quantitative proteomic analysis of some animal hair fibers - Part 2: Peptide detection using MALDI-TOF MS Standards for stipulating a test method for identification of cashmere fibers applying protein analysis technologies

Division in Charge

International Standardization Division, Industrial Science and Technology Policy and Environment Bureau