| The Pinus pumila nut protein is a kind of excellent plant protein resource,which has a good value of exploitation,and it has the functions of softening blood vessel,nourishing and strengthening,beautifying and beautifying the face.In this paper,the extraction of protein,physical and chemical properties,functional properties and proper oxidation of protein from Pinus Pumila were studied.The main conclusions are as follows:This experiment takes Pinus pumila seed meal (protein content is 45.39%) as the raw material,single factor and response surface analysis were used to study the optimum extraction process of Pinus pumila nut albumin,globulin,gliadin and glutenin.The results showed that the optimum extraction parameters of albumin were:ratio of liquid to material 44:1,temperature 45.4℃ ultrasonic power 240 W,ultrasonic time 40 min,the yield of albumin in Pinus pumila meal was (32.59±0.70)%;The optimum extraction parameters of globulin were as follows:ratio of liquid to material 45:1,concentration of salt solution 1.83%,ultrasonic power 240 W,ultrasonic temperature 45℃,the yield of globulin in Pinus pumila meal was(8.48±0.25) %;The optimum extraction conditions of gliadin were as follows:ratio of solvent to material 26:1,concentration of ethanol solution 74.5%,ultrasonic power 240 W,ultrasonic temperature 45℃,the yield of globulin in Pinus pumila meal was gliadin(0.92±0.04) %;The optimum extraction conditions of glutenin were as follows:ratio of liquid to material 26:1,ultrasonic time 42 min,ultrasonic power 240 W,ultrasonic temperature 45℃,pH 9,the yield of glutenin was (15.22±0.30)%.The physical and chemical properties of pine nut albumin,globulin and glutenin were analyzed.The purity of pine nut protein was determined by Kjeldahl method.The purity of albumin,globulin and glutenin were 79.22%,80.52% and 78.96% respectively.The results of determination of the isoelectric point of pine nut albumin,globulin and glutenin were 4.2、3.8 and 4.4,respectively.The amino acid composition of the three proteins was basically reasonable.The highest amino acid content was 80.58 g/100g of pine nut globulin,78.83 g/100g of glutenin and 77.82 g/100g of albumin,the contents of glutamic acid and arginine were the highest among the three proteins,and the molecular weight of the three proteins was about 9.81～37.47 kD by SDS-PAGE.The functional properties of pine nut albumin,globulins and glutenin were studied.The surface hydrophobicity of three protein components was determined by ANS fluorescence probe.The order of hydrophobicity of three protein components was glutenin (932)> globulin(773)> albumin (419).The solubility of pine nut protein was the best when the temperature was 50℃,the solubility was 56.37%,the solubility of secondary globulin was 40.38%,and the solubility of glutenin was 23.36%.The water-holding capacity of pine nut protein was 2.59 g/g for albumin,1.49 g/g for globulin and 1.91 g/g for glutenin,and 3.99 g/g,3.25 g/g and 3.54 g/g for oil-holding capacity.The emulsifying ability of albumin,globulin and glutenin were 12.58、4.49 and 10.91 m2/g,respectively,and the emulsifying stability were 55.38%,46.19%and 41.2%,respectively,the foaming ability of the three proteins was 90.23%,54.36% and 45.65%,respectively.The foaming stability of albumin was 55.67%,glutenin was 19.23%,globulins was 11.33%.The functional properties of albumin were the best among the three proteins.The experiments were conducted with hydroxyl radical oxidation system (0.1 mmol/L FeC13 and 0.1 mmol/L ASC) at different concentrations of H2O2(0.1,0.5,1,5,10,15 mmol/L) for 1、3 and 5 hours,respectively.The effect of oxidation treatment on the functional group structure and emulsifying property of pine nut albumin was analyzed.The results showed that with the increase of H2O2 concentration and the increase of oxidation time,the content of carbonyl group and the content of free sulfhydryl group and total sulfhydryl group in pine nut albumin increased continuously,which indicated that the degree of oxidation of pine nut albumin increased continuously.When the concentration of H2O2 was 1 mmol/L for 5 h,the best emulsifying stability of the protein was 33.97 m2/g,and when the concentration of H2O2 was 10 mmol/L for 1 h,the best emulsifying stability of the protein was 92.38%.The results showed that proper oxidation could improve the emulsifying ability and the emulsifying stability of the protein.After the oxidation of pine nut albumin by hydroxyl radical,the protein degraded.With the increase of the oxidation degree of pine nut albumin,the density of the original band of SDS-PAGE decreased gradually. |
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