Influence of equibiaxial extensional strain on stress relaxation of glycerol plasticised wheat gluten

• Autores: Min Zuo, Yihu Song, Qiang Zheng
• Localización: Journal of the science of food and agriculture, ISSN 0022-5142, Vol. 88, Nº 13, 2008, págs. 2350-2356
• Idioma: inglés
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• Resumen

  • BACKGROUND: Glycerol plasticised wheat gluten shows advantages for non-food applications such as biodegradable package films and bioplastics because of their abundant resources, low cost, good biodegradability and suitable mechanical and oxygen barrier properties. The intention of this study was to evaluate to the equibiaxial stress relaxation of 400 g kg−1 glycerol plasticised gluten at different biaxial strains at room temperature for a better understanding of the processibility. RESULTS: The plasticised gluten shows significant stress relaxation and the spectra span over six decades of time at biaxial strains from 0.03 to 1.51. Plotting the instantaneous modulus against strain reveals strain softening and strain hardening at strains below and above 0.25, respectively. The relaxation modulus as a function of time can be fitted to the Kohlrausch–Williams–Watts equation. CONCLUSION: These results suggest that stress relaxation of plasticised gluten is highly dependent on strain level and biaxial deformation accelerates the network relaxation by widening the distribution of relaxation times. Copyright © 2008 Society of Chemical Industry