Study On Extraction And Functional Properties Of Seabuckthorn Seed Meal Protein

The byproduct of seabuckthorn seed after oil extraction, Seabuckthorn seed meal(SSM), which was rich in protein, is a good vegetable protein resource. This study using SSM as the material, invsetigated the extraction methods of ethanol-leached and alkali-extracted SSM protein and the functional properties of alkali-extracted seabuckthorn seed meal protein(ASP) compared with soybean protein isolate(SPI). There were very limited articles about the functional properties of seabuckthorn protein, therefore the thesis made the basic research in order to supply the foundation for the following research and application of SSM protein and constribute to comprehensive utilization of SSM.Firstly, ethanol leaching prcocess of ethanol-leached seabuckthorn seed meal protein(ESP) and procyanidins was studied after pre-treament of SSM.According to the content of protein and procyanidins, the optimal parameters were determined as follows: degree of grinding 80, ethanol concentration 70%, ratio of SSM to ethanol l:6, 50℃, 3 times and 1h each time.The protein content of ESP was 52.85% and the content of procyanidins was 27.94% in crude extract.Secondly, alkali extraction and acid precipitation process of ASP was studied. According to alkali extraction rate and protein content, the optimal parameters were determined as follows: ratio of SSM to water l:14, pH11, 60℃, 80min . The alkali extraction rate was 53.08%, the protein content of ASP was 80.51% and the yield was 46.94%.Then the protein in residue was further extracted by Alcalase. According to the residue-protein extraction rate, the optimal parameters were determined as follows: Alcalase addition 240 U/g, ratio of residue to water l:10, 60℃, 60min. The residue-protein extraction rate was 24.13% and the protein content of residue-protein was 61.77%.Finally, the functional properties of ASP were studied. Amino acid analysis of ASP indicated that Met and Cys were the first limiting amino and the proportion of essential amino acid was more balanced than SPI. Thermal stability test of ASP indicated that the endothermic peak of ASP was 64.84℃and heat of denaturation was 2.9230 J/g. ASP was mainly composed of globulins (50.19%) and albumins (28.72%).The solubility, water holding capacities and emulsifying activity were affected by the environmental factors, such as alkali extraction pH, extraction temperature and ionic strengths. The surface hydrophobicity index of SPA was higher. The solubility, water holding capacities, oil holding capacities, emulsifying stability and foaming capacity were poorer than SPI, but emulsifying capacity and foaming stability at the pH7.0 and room temperature. Most of indexes of functional properties at pH5.0 were the lowest.