Protein Extraction And Functionality Research Of Xanthoceras Sorbifolia Bunge Seeds

Xanthoceras sorbifolia is a unique oil tree species in China,and its seeds are rich in fat and protein.In order to fully exploit and utilize the resources of Xanthoceras sorbifolia bunge,and realize its high value-added processing and utilization,it is necessary to carry out systematic basic analysis and research on its protein.To determine the water-holding,oil-holding,solubility,emulsifying,foaming,gelling,thermal stability and other functional properties of the Xanthoceras sorbifolia bunge protein,by analyzing its amino acid composition and measuring the digestibility in vitro.A preliminary nutritional evaluation was carried out to provide a scientific basis for protein product development and future industrial development.The main results are as follows:In this paper,the extraction methods and functional properties of Xanthoceras sorbifolia bunge protein were studied,including extraction and analysis of the protein components of the Xanthoceras sorbifolia Bunge,the optimization of protein extracted by Alkali-Solution and Acid-Isolation,and the denaturing polyacrylamide gel electrophoresis?SDS-PAGE?was used to analyze and compare the molecular components of each protein and the molecular weight of the total protein subunits,which could lay a foundation for efficient extraction of Xanthoceras sorbifolia bunge protein.To explore the extraction method and SDS-PAGE analysis of the protein and its protein components from Xanthoceras sorbifolia bunge.The results showed that the protein content of the Xanthoceras sorbifolia bunge kernel was26.29%,and the protein content was 62.04%after degreasing.The classification extraction method were used to extract four main protein components from Xanthoceras sorbifolia bunge,the results indicated that the contents of globulin,albumin,glutenin and gliadin were 26.38%,21.50%,2.49%and 1.99%,respectively.Through a direct extraction method,the extraction rate of water-soluble protein,salt soluble protein,gliadin and alkali soluble protein were 34.63%,75.57%,7.26%and 80.09%,respectively.Orthogonal experiment was used to carried out optimize the conditions of extracting the protein of Xanthoceras sorbifolia bunge protein by Alkali-Solution and Acid-Isolation.The results displayed that the extraction rate of protein was up to84.06%,the protein yield was 36.40%,and the purity of protein powder was83.92%under the conditions of extracting material to liquid was 1:11,the extraction pH was 11,the extraction temperature was 40?,and the extraction time was 40 min.The results of the SDS-PAGE electrophoresis analysis showed that the subunit molecular weight of Xanthoceras sorbifolia bunge protein was distributed between 20 kDa and 60 kDa.And obtained the main subunit molecular weight in four kinds of protein components.This method could provide the basis for further research on the protein components of Xanthoceras sorbifolia bunge.Study on the functional characteristics of the protein of Xanthoceras sorbifolia bunge.The protein powder extracted by Alkali-Solution and Acid-Isolation was used as an experimental material to determine the functional properties of protein such as water holding capacity,oil holding capacity,solubility,emulsifying property,foaming property,gelation and thermal stability.The results indicated that Xanthoceras sorbifolia bunge protein had good oil retention and good water holding capacity at high temperature or low pH.pH had a great influence on the functional properties of the protein.When the pH was approached to the isoelectric point of protein?pH 4.6?,the emulsification and foaming properties of protein were weakened due to the decrease of solubility of protein.Under strong acid or alkali conditions,the solubility of protein was higher,so its emulsifying and foaming properties were remarkably enhanced.The solubility,emulsification and foaming ability of the protein could be improved by proper heating treatment,and high temperature treatment could effectively improve protein gel properties.The emulsification of protein was greatly affected by salt ions,and no emulsion could be formed in the range of NaCl concentration of 0.2¹.2 mol/L.The optimal protein concentration of the Xanthoceras sorbifolia bunge protein forming gel was 10%.With the increase of CaCl₂ concentration,the gel properties of the protein decreased gradually.Thermal stability analysis of Xanthoceras sorbifolia bunge protein showed that the denaturation temperature was 83.4?,which was lower than that of SPI.Nutritional evaluation of Xanthoceras sorbifolia bunge protein.Protein digestibility was measured by simulated digestion test in vitro,and combined with amino acid composition analysis and amino acid score,a preliminary comprehensive evaluation of nutritional value was carried out.Amino acid composition of Xanthoceras sorbifolia bunge after degreasing and protein powder was determined by automatic amino acid analyzer.The results showed that 17 kinds of amino acids were detected in both samples except for Tryptophan?Try?,of which Glutamic acid?Glu?>Arginine?Arg?>Aspartic acid?Asp?.There were 7 essential amino acids in both samples.The contents of Glu and Arg were higher.The total concentration of essential amino acids in the defatted powder was 19.496 g/100g,accounting for 27.9%,and the total concentration of essential amino acids in protein powder was 26.082 g/100g,accounting for 29.4%.According to the amino acid score,the contents of Valine?Val?,Isoleucine?Ile?and Leucine?Leu?were close to the standard pattern spectrum,and Methionine?Met?was the first limiting amino acid of Xanthoceras sorbifolia bunge protein.The digestibility of pepsin and trypsin were determined by simulated digestion in vitro.The optimum digestion concentration of pepsin was 0.8 mol/L and that of trypsin was 2.8 mol/L.Under this condition,the simulated digestibility of Xanthoceras sorbifolia bunge protein in vitro was98.43%,which was higher than that of soybean protein isolate.It was indicated that Xanthoceras sorbifolia bunge protein was a high-quality protein easily digested and absorbed by human body.