Study On Preparation And Properties Of Gluten Protein Fiber

Wheat gluten is the gelatinous substance left after starch and other water-soluble components have been removed from wheat dough.It is mainly composed of glutenin and gliadin.Most of the gluten resources are currently used in the food and feed industry.In order to make the gluten get high value utilization,based on wheat gluten as raw material,the glycosylation reaction between carboxymethyl chitosan(CMCS)and gluten was induced by transglutaminase(TGase),the glycated gluten was then prepared into fibers by wet spinning.The effects of glycosylation modification conditions on the mechanical performances of wheat gluten protein fiber(WGPF)were investigated,and the optimal conditions for glycosylation modification were obtained.Subsequently,the WGPF was treated with glutaraldehyde solution to further enhance its mechanical performances.Finally,the structure and related properties of WGPF were studied.Firstly,the technological conditions of preparing WGPF were optimized.When the concentration of gluten protein was 19%,the p H of spinning solution was 7,and the coagulation time was 20 min,the unmodified WGPF was 0.49±0.02 c N/dtex in breaking strength and4.86±0.38% in breaking elongation,showing the best mechanical performances.The effects of glycosylation modification conditions on the WGPFs' mechanical performances were then studied,and the optimum conditions of glycosylation modification were determined as follows: the concentration of gluten protein was 4%,CMCS content was 104 mg/g,TGase content was 0.52 U/g,reaction temperature was 40°C,reaction time was 40 min.Under these conditions,the modified WGPF was 0.70±0.04 c N/dtex in breaking strength and11.01±0.93% in breaking elongation,which were respectively 42.86% and 126.54% greater than those of the unmodified WGPF.The results of gel electrophoresis and Fourier transform infrared spectroscopy(FT-IR)indicated that the gluten protein and CMCS were crosslinked in the process of glycosylation modification,and the modified WGPF contained an increased amount of ?-corner.The results of scanning electron microscopy(SEM)showed that the surface of the modified WGPF became smooth and the number of pores in the cross-section decreased.In addition,the thermal stability,acid and alkali resistance,moisture and heat resistance of modified WGPF were improved,the standard moisture regain was increased,and the dyeing performance of reactive dyes on fibers was also improved.Compared with the unmodified WGPF,the dye fixing rate of modified WGPF was more than doubled at room temperature.On the basis of glycosylation modification,the modified WGPF was treated with glutaraldehyde solution to obtain composite treated WGPF.The technological conditions of glutaraldehyde treatment of modified WGPF were then optimized.When the concentration of glutaraldehyde was 1%,temperature was 35°C,time was 4 h,p H was 8,the composite treated WGPF had the best mechanical performances.Under these conditions,the obtained WGPF was 1.25±0.04 c N/dtex in breaking strength and 53.34±0.83% in breaking elongation.After glutaraldehyde treatment,the mechanical performances of the composite treated WGPF were similar to those of wool,which can meet the strength requirements of textile applications.FT-IR analysis suggested that the composite treated WGPF contained an increased amount of?-helix and ?-corner.SEM results revealed that the surface of composite treated WGPF had obvious longtitudinal stripes,the cross-section structure was uniform and compact,and the number of pores was obviously decreased.In addition,the standard moisture regain and thermal stability of composite treated WGPF pointed to a further increase,and the fibers' acid and alkali resistance,moisture and heat resistance in water were improved,the fixation ability of reactive dyes on composite treated WGPF was enhanced,and the fibers had excellent dyeing performance.