Application of the Products from the Maillard Reaction of Polyglutamic Acid and Glucose to Prepare Colored and Bioactive Silk.

Wen Zhang,Ren-Cheng Tang

doi:10.3390/polym10060648

Abstract

In this work, the Maillard reaction of polyglutamic acid (PGA) and glucose (Glc) was studied, and its functional, polymeric, and colored products were used to dye silk fiber with the aim of imparting bioactivities to silk. The UV–Vis spectroscopic analysis, which was employed to monitor the reaction, revealed the rapid formation of yellowish-brown products at pH 12 and 90 °C, and the great impact of glucose content on the quantity of the products. The FT-IR analysis validated the formation of melanoidin colorants. The silk fiber dyed with the PGA/Glc reaction products at pH 3 displayed a yellowish-brown color, and had very good wash and rub fastness, but poor light fastness. The incorporation of the UV-absorbing moiety into the PGA/Glc reaction products enhanced their light stability. The SEM analysis revealed that the dyed silk fiber was covered by polymeric substances. The dyed silk exhibited durable antibacterial activity against Staphylococcus aureus and Escherichia coli, and good antioxidant activity. This research expands the application field of the Maillard reaction and provides a novel and eco-friendly approach to prepare the colored and bioactive silk materials.

Highlights

The Maillard reaction is a non-enzymatic browning reaction between amino-containing compounds and reducing sugars. This reaction involves a series of reaction steps including sugar-amine condensation, Amadori rearrangement, sugar dehydration, sugar fragmentation, amino acid degradation, aldehyde-amine condensation, formation of heterocyclic nitrogen compounds, etc., which produce dark brown to black colored polymers and copolymers, known as melanoidins [1]
Carbohydrates are used as retanning agents to increase the affinity of reactive dyes to crust leather; to achieve this purpose, the modified Maillard reaction is employed, where crust leather is firstly treated by carbohydrates and oxidized by potassium iodate [5]
The polyglutamic acid (PGA) and Glc reaction products had the maximum absorption at 264 nm, and displayed some absorption in the visible region

Summary

Introduction

The Maillard reaction is a non-enzymatic browning reaction between amino-containing compounds and reducing sugars. This reaction involves a series of reaction steps including sugar-amine condensation, Amadori rearrangement, sugar dehydration, sugar fragmentation, amino acid degradation, aldehyde-amine condensation, formation of heterocyclic nitrogen compounds, etc., which produce dark brown to black colored polymers and copolymers, known as melanoidins [1]. The Maillard reaction of glucose, xylose, dextrose, and galactose with amino groups in wool fiber has been applied to enhance the uptake of reactive and acid dyes [4]. The Maillard reaction has been applied to the in situ coloration of wool, silk, and nylon fibers with various reducing sugars, which imparts yellow and orange-brown colors, as well as good antibacterial performance to these

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Conclusion