| Ginkgo biloba L. (usually called ginkgo), as one of the most ancient trees in the world, originated from China and has been titled as living fossil, panda of the plant kingdom. And ginkgo seed has been used as foods and medicines for a long history in China, but the major active parts and compounds were less known to people. Until recent years, some researches show that ginkgo seed contains plenty of nutrients, such as fatty alcohols, flavonoids, proteins, polysaccharides, fatty, starch, vitamins, and trace minerals etc., and therefore has good efficacies on anti-aging, anti-fatigue, anti-anoxia, and relieving cough.Take ginkgo as materials, content of moisture, protein, amino acids, ginkgo oil, flavones, and terpene lactones were measured in this paper, and the best conditions for extracting ginkgo oil were determined as well. The results showed: ginkgo seed contained total protein of 9.84%～11.88%; moisture of 55%～60.01%; flavones of 0.0257%～0.0463%; terpene lactones of 0.00385%～0.0181%; 16 kind of amino acid; ginkgo oil of 3.6%~7.11%; best conditions for extracting ginkgo oil were as follows: supercritical fluid extraction ( SFE) at 40℃, 20MPa, 15 L/h, for 3 hours.This paper emphasized on the protein in ginkgo seed, mainly about its extraction, purification, preparation process and related analysis methods. Through a series of experiment, we can get following conclusions: Kjeldahl could be used in solid and liquid protein sample, Coomassie Brilliant Blue was proper for liquid protein sample determination (Y=23.631X-0.0689, R2=0.9876), Biure method was used in messuring peptides content (Y=0.2475X+0.0004, R2=0.9992). Take 0.14 mol/L NaCl solution as solvent with solid/liquid ratio of 1:7, pH of 8, and 30 min each for 3 times, we can get the protein yield of 4.38%; 60% and 70% (NH4)2SO4 (pH=6) were used to precipitate protein for 12h and cut the protein with molecular weight of 10 000~30 000MW by membrane facility; DEAE-cellulose resin was chosen to purify the sample, and the buffer system should be maintained at pH7.5. Select 0.4mol/L NaCl solution (pH=7.5) as the elute solution, 3 kind of protein with different molecular weight of 21.4 KDa,17.9 KDa and 15.8 KDa were acquired. Purified sample contain protein of 62.8%, was better nutrient in amino acids composition, and with the max UV absorbency of 215nm.Results from MALDI-TOF-TOF mass spectrum were showed as follows: belt1 was a fragment of protein legumin (gi/949869), 11S-globin, which was 51418Da and with pI of 8.69, and the score was 121, the coverage was 38%. Belt2 was a new protein with two major peptide sequence of I/L S A I/L T A D I/L G N W Q/K D S P G I/L R (m/z:2131) and A A Q/K V D S S S D V Y A S D N I/L P G G N R (m/z:2338) respectively. Belt3 was a combined protein by belt1 and belt2.Composite of Ginkgo protein and a preparation process of peptides were studied, the results showed: water-soluble, salt-soluble, alcohol-soluble, alkaline-soluble protein were respectively 22.20%, 17.99%, 1.73%, 30.32% and 25.97%. Best conditions for preparing peptides were as follows: Alkaline protease 2g(in 10g material), temperature of 47℃, concentration of 2.17%, time of 6h, pH of 9, and in which condition we can get a high DH% of 67.65%, row peptides of 2.2%(in material) after been treated, and the peptides was 53.7%(in row peptides). After been hydrolyzed, this peptide was better for human health due to its proper amino acids constitution.
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