Influence of Sugar Structure on Coloration of Wool Fibers by Reducing Sugars

• Published in: Journal of Fiber Science and Technology Vol. 76; no. 4; pp. 127 - 133
• Main Authors: Ohe, Takeru, Yoshimura, Yurika
• Format: Journal Article
• Language: Japanese; English
• Published: The Society of Fiber Science and Technology, Japan 20.04.2020
• ISSN: 2189-7654; 2189-7654
• DOI: 10.2115/fiberst.2020-0014

We have experienced in our daily living well that foods including both reducing sugar, such as glucose, and amino compound, such as amino acid and protein, become yellow or brown after the heating process or long storage such as the fermentation process. These coloration reactions are called the Maillard reaction, melanoidin reaction or browning reaction. It was clarified in our previous works that protein fibers such as wool, silk, and leather, were also colored brown by reducing sugars. Interestingly, each usage of isomeric reducing sugar afforded the different color density of these protein fibers. For example, the wool fibers colored by D-galactose showed the deepest coloration in the hexoses, such as D-glucose, D-galactose, and D-mannose. In this paper, various reducing sugars having different carbon number or different configuration of hydroxyl groups were investigated as their color precursors to clarify the mechanism of the above results in detail. Obtained results showed that both the stability of their chain structure in an aqueous solution and the configurations of their hydroxyl groups affected their color density largely. As a result, D-erythrose, which is one of tetrose, gave the deepest coloration in the reducing sugars examined here.