The Extraction And Purification Of γ-Poly Glutamic Acid And Its Application

γ-poly-glutamic acid is a kind of poly homopolymer polypeptide,it is a kind of anionic polymer which is formed by the combination of D or L glutamic acid through the formation of gamma amide bond between alpha amino group and gamma group.With strong water retention,plasticity,fibrous,silm,moisture and oxygen resistance,biodegradability and strong water absorption,it is a new kind of natural macromolecule polymer which can be used for environment and human body,widely used in food,medicine,agriculture,cosmetics,etc.In this paper,the properties of y-PGA were studied in four aspects:the extraction and purification of poly glutamic acid,ice cream,corn noodles and cosmetics.By using organic solvent and chemical solvent extraction,plate and frame filter two methods of y-PGA fermented liquid to study the best extraction of γ-PGA.Organic solvents and chemical solvents were selected to extract different kinds of extractions,the ratio of ethanol to fermentation liquid,the concentration of ethanol and the extraction times of ethanol,to determine the optimum alcohol extraction process.For the frame filtering,dilution of fermentation liquid by different multiples,by comparing the different dilution filtrate quality to determine the optimal dilution of fermentation liquid,determine the optimal process plan frame filtering,to study and carry out the concentration process of plate and frame filter filtrate.The experimental results showed that the ethanol fermentation liquid extraction effect is better,the extraction rate and quality than the frame filtering effect is good,when the ratio of ethanol to the fermentation broth was 4:1,the best effect was obtained by three times.The maximum extraction rate was 67g/L,and the pH value was 8.13.On the basis of traditional ice cream formula,this paper studied the process of adding ice cream with γ-PGA as stabilizer and thickener,the expansion rate,viscosity and melting rate were used to evaluate the quality of ice cream,and the ice cream was optimized by single factor experiment and Box-Behnken response surface experiment,on the basis of the optimized formula of ice cream,adding y-PGA as stabilizer and thickener of ice cream,y-PGA was compared with the traditional ice cream additive.The results showed that by adding 9%milk,11%cream and 11%sugar as raw material,and the y-PGA 0.03%as stabilizer and thickener,through raw material mixing,sterilization,high shear thinning,homogenization,freezing,aging hardening,the best quality of expansion of ice cream was 67.75%,the melting rate was 35.28%,the viscosity was 2456.9mPs.With 1%gelatin and y-PGA as modifier of corn noodles,the mixed flour quality characteristics and tensile properties of corn noodles,pasting properties,texture analysis,broken rate,dry matter loss,water loss rate,SEM image analysis and sensory evaluation,effect of y-PGA on corn noodles.The results showed that the addition of y-PGA had a good effect on the quality of corn noodles,when the content of y-PGA was 0.15%,the flour properties and tensile properties of blended flour were good,when starch was gelatinized,y-PGA can inhibit the disintegration of starch granules,which can increase the difficulty of starch gelatinization.It can be found that the texture of the noodles with γ-PGA is better than that of adding gelatin,and the texture of the noodles is better than that of 0.1%～0.15%.Sensory evaluation is a kind of texture evaluation,through the analysis of sensory evaluation can be found,adding gelatin noodles had advantages in taste,other than adding y-PGA.The results of SEM showed that adding 0.15%y-PGA dough less empty,most of the starch granules were wrapped in gluten,and adding dough gluten network structure of gelatin fracture occurred more serious.γ-PGA has a strong moisturizing effect,γ-PGA as a moisturizing agent added to skin care products can be a good improvement in the skin.Experimental study on optimal water holding concentration of γ-PGA,adding y-PGA to moisturizing cream,by contrast with moisturizing cream,a moisturizing agent,hyaluronic acid and vitamin B5,study the effect of adding three kinds of y-PGA,hyaluronic acid and vitamin B5 on the skin.The results showed that the γ-PGA was good when the concentration of 1%,so it was best to add the y-PGA to the cosmetics.The moisture content of skin with y-PGA was measured by CM825 moisture test probe for a short time,and the highest moisture content was 86a.u.,for a long time the use of y-PGA moisturizing cream for 20 days,the skin moisture content was relatively high,84a.u.Short term and long term use of y-PGA moisturizing cream,skin epidermal water loss rate has decreased,with the increase in the use of time,the skin surface water loss rate had decreased,for skin elasticity,short-term use did not have a good result,but long-term use for the elasticity of the skin had a good improvement,the use of three long-term moisturizing cream,the best effect of containing γ-PGA moisturizing cream on the skin elasticity,containing γ-PGA moisturizing cream for 20 days the skin’s elasticity valued 0.72.