Study On The Extraction And Functional Properties Of Flaxseed Gum From Flaxseed Flake

Taking flaxseed flake as a raw material, the extraction and functional properties of flaxseed gum was investigated in this thesis, including extraction and deproteinization of flaxseed gum, monosaccharide composition analysis of polysaccharide from flaxseed gum, functional properties comparison of flaxseed gum and other gums, and preparation and analysis of sulfated flaxseed gum.Through single factor and orthogonal experiments, the effect of various factors on extraction and deproteinization of flaxseed gum was studied, and the process parameters were optimized in this paper. The results showed that the optimum conditions for the extraction process was extraction temperature of70℃, pH of2.0, solid-liquid ratio1:21and alcohol precipitation concentration of75%, and the optimum conditions for the deproteinization was adding amount of calcium hydroxide with0.30g per50mL water extract, temperature of80℃, holding time50min. Capillary gas chromatography showed that flaxseed gum was composed of rhamnose, arabinose, fucose, xylose, mannose, glucose, galactose, and the mass fraction of these monoses was12.13%,6.83%,4.30%,12.70%,3.75%,10.15%,15.30%respectively.The functional properties of flaxseed gum were compared with arabic gum and xanthan gum. Arabic gum showed good solubility and transparency, next came xanthan gum, and there followed flaxseed gum; The viscosity of flaxseed gum was lower than xanthan gum and higher than arabic gum under same mass fraction. For three kinds of gums, their viscosities decreased with the temperature increasing, increased at first and then decreased with pH increasing. Flaxseed gum had better foamability and stability of foam, and its foamability was superior to arabic gum and xanthan gum; In an oil-water ratio of1:1, emulsifying capacity of xanthan gum was the best, flaxseed gum was only next to it, and arabic gum had the poorest emulsifying capacity; In an oil-water ratio of1:10, emulsifying capacity of flaxseed gum was better than arabic gum, but much lower than xanthan gum; Freezing and thawing had no negative effect on three kinds of gums’ viscosity, and they had freezing-resistance to a certain degree; All the three had salt tolerance in some degree, among which flaxseed gum was more obvious; It showed that there was no obvious synergistic effect of flaxseed gum with arabic gum and xanthan gum.Flaxseed gum was sulfated by the means of Wolform and sulfuric acid respectively, and the technical parameters of the two processes were optimized. The optimal parameters in Wolfrom method were20mL of ester reagent(chlorosulfuric/pyridine ratio1:2) per0.5g flaxseed gum, temperature60℃and reaction4h, and the degree of substitution was1.34; The optimal parameters in sulfuric acid method were6mL of concentrated sulphuric acid,2mL of butanol per0.5g flaxseed gum and temperature60℃, and the degree of substitution was0.54.Sulfated flaxseed gum was analyzed. The results showed as follows:the viscosity decreased, and solubility and transparency increased, obviously; Foamability was higher than non-modified flaxseed gum, but stability of foam decreased, obviously; Emulsifying capacity decreased obviously, and sulfated flaxseed gum had worse emulsifying capacity by the means of sulfuric acid than Wolfrom; The infared spectrum showed that some hydroxyl was substituted by sulfate group; Microstructures of flaxseed gum with different degree of substitution were observed by scanning electron microscope. Sulfated flaxseed gum showed obvious loose state.