Extraction Of Oil And Protein From Macadamia Nut,Properties Analysis,and Protein Preliminary Purification Analysis

Macadamia nuts have rich nutritional value,considered as one of the high quality oil and protein sources.This research took macadamia nuts as raw materials,the main composition was systematically analyzed.Using aqueous extraction method to determinate the best extraction condition of macadamia nuts oil and comparing oil properties.And the best extraction condition of macadamia protein from macadamia meal was detected,then analysis the functional properties and structure properties of macadamia proteins from different extraction methods.Finally conducted purification analysis of macadamia nuts protein.The experimental results showed that:(1)Fat content is a maximum of 76.50%in total;protein content is 9.20%;soluble sugar is 7.40%;water content is 1.67%;and ash content is 1.21%.(2)Using aqueous extraction method to extract macadamia nuts oil,the optimal conditions for extracting oil from this material were determined to be:material/liquid ratio,1:3 g/mL;nature pH,pH6.4;extraction duration,1h;and centrifugal force,4800 r/min.A oil extraction rate of 67.50%was obtained under the optimal extraction conditions.The Macadamia nuts oil obtained by aqueous method was transparent,pale yellow.The physicochemical properties results showed that the acid value and peroxide value of oil were lower than the corresponding value of the national quality standards.And the pH condition of aqueous extraction has a certain influence on Macadamia nuts oil.Oil extracted with aqueous extraction from Macadamia nuts was detected for fatty acid analysis.The result showed that Macadamia nuts oil contained 10 kinds of fatty acids,mainly the unsaturated fatty acid.According to the content of the level,the order is oleic acid,palmitic acid,arachidonic acid,the twenty carbon acid,docosanoic acid,tetradecanoic acid,wood tar acids,linoleic acid,erucic acid and myristoleic acid.(3)Choose alkali-solution and acid-isolation method extract protein from Macadamia nuts meal(after solvent extraction of macadamia nut oil),determination of the isoelectric point is pH4.5.Extraction of macadamia nut proteins by Osborne method,Globulin>Albumin>Glutenin>Gliadin,four proteins percentage is 53:33:12:2.Use alkali-solution and acid-isolation method,TRIS-HCL method,salt solutionmethod(NaCl)three kinds methods extract macadamia nut proteins.The yield of alkali-solution and acid-isolation method was highest,reach 36.60%,protein content is 88.90%;the yield of salt solutionmethodwas 19.70%,protein content is 86.10%;the yield of TRIS-HCL methodwas lowest,reach 15.20%,protein content is 80.30%.Therefore select alkali-solution method to optimize the extraction process,the optimal conditions for extracting proteins from this material were determined to be:material/liquid ratio,1:50 g/mL;pH 10;temperature 45 ℃;extraction duration,1.5 h.A protein extraction rate of 86.75%was obtained under the optimal extraction conditions.(4)Macadamianut protein solubility was affected by pH,in the range of pH5.0-9.5 wasless than 30%.With the increase of buffer pH,the emuLsion ability of macadamia nut protein increase.The emulsification stability of protein extracted by three kinds methods was highest in distilled water.The fluorescence intensity and the hydrophobic values of salt solutionprotein were higher than alkali-solution and acid-isolation method protein and TRIS-HCL method protein.The structure morphology of salt solutionproteinunder scanning electron microscope can see spherical body obviously,different from the lens structure in alkali-solution and acid-isolation method protein and TRIS-HCL method protein.Macadamia nut protein mainly containing glutamic acid and arginine.Three kinds of extracting method protein for have the same amino acid composition,but different contents.(5)Macadamia nut protein is mainly low molecular weight protein,molecular weight mainly in 14.4-50.0 KDa.There are missing bands between three methods of extracting protein isolates and raw material.The preliminary purification of Macadamia nuts alkali-solution and acid-isolation method protein was analyzed.The Macadamia nut protein molecular weight were divided into 7 groups,and the content of group 2 was the highest.In the three different sample volume(25 μL,100 μL,500μL)peak curves,sample volume500 μL response curve was larger,and the peak is the best.Three different flow rates(0.4,0.5,0.6 mL/min)peak curves appeared the same shape,showed different flow rates was not significant effect on peak.Three different eluents(0.05M pH7.0 PBS,0.20M pH10,83 Na2C03-NaHCO3,0.20M pH 12.0 Na2HPO4-NaOH)peak curves,the pH 7.0 PBS curve appear best elution peak,the other two peaks are not obvious.