| Soybean(Glycine max(L.) Merr) being as a soja subgenus cultivar which belongs to pulse family has a long time and wildcultivation in the world,and it is a good food providing various proteins. Wherease the scare of methionine affects the utilation rate of soybean nutition,among which,trypsin inhibitor,as a digeative enzyme during development,is an important anti-nutrition factor.Trypsin protease inhibitor can decrease the utilization of protein,and result in the loss of soybean nutrition for human beings.So decreasing the trypsin inhibitor proteinase activity and blancing the composition of amino acid is necessary and important to improve usage rate.The study showes that germination of seed can enhance the nutrition utilization derive from inhibition of the activation of trypsin protease inhibitor. Given the health of human beings,it is necessary to find optimal germination conditions which absolutely improve soybean protein nutrition in the future.Considered the importance of this study,ZhongNong 056444 was used as a material to study the tendency of imbibiton,metabolism of proteins,the change of trypsin protease inhibitor and peptidase.A secondary orthogonal regression design of three factors model was constructed based on the data of soluble proteins and species activity of trypsin protease inhibitor to explore the optimal conditions of germination.The result of this study was shown as following:1) The germination experiment and protein metabolism result was that imbibition processes could be classified into three phases.The reversal points appeared at 12 h and 27 h respectively during germination,and the optimal conditions was Ph 7.5 and 20℃under semi-seed soaking condition.2) Temperature,pH and germination time affected the soybean protein metabolism during germination,and among which,the time and temperature were key factors.The maximal soluble protein appeared in 12 h and 72 h in imbited seed,and it was enhanced 16%and 20%respectively than that of dry seed,The activity of protease and peptidase showed no significant change when seed was imbibed between 0～39 h,however,novel enhancement was observed between 39～72 h,and decreased in the later time.During this period,proteinase and content in 72 h was improved 65%and 78%respectively during imbibition than that of dry seed.Peptide and N-anmino enhanced their level in 96 h in germinated seed,and enhanced their level for 39%and 152 respectively than dry seed.The soluble protein content was minimalest when seed was geriminated under 20℃for 24 h.In addition,the maximum of soluble protein content was shown in pH 6.0 and pH 8.5,and was improved for a 5.1%.The most optimal pH condition for peptidase was 5.0～6.0,and 11.7% improvement was observed,pH 9.0 is the optimal condition for the activity of exopeptidases with 39% enhancement.The content of peptide and N-amino acid was the most in pH 6.0 than that of others.3) Significant effect on the activity or species activity of trypsin protease was found when the seed was germinated,and the species activity was the most sensitivity in the germinated seed.No change was found at 0～72 h.However,the activity of trypsin protease inhibitor began to decrease after 72 h imbibition,.The activity and species activity of trypsin protease inhibitor was decreased to a 90%and 68%respectively in this time than the dry seed,and was only 69%and 53%after 96 h imbibtion.No significant effect was found for the pH on the activity of trypsin protease with no more than 10% enhancement.4) From the result of regression equation,the trend of soluble protein and trypsin protease activity under treatment of temperature,pH and germinated time was notable,and it could correctly elucidate the tendency of soluble protein and the species activity of trypsin protease inhibitor during germination under above conditions.5) The increase of endopeptidases was enhanced for a 24%at 9 h,while no change was showed in the following time,although high level was showed during experiment time.Under optimal temperature and pH conditions,the activity of endopeptidases was only improved no more than 6%than unavailable conditions.6) The 5%improvement of essential amino acid content/total amino acid amino was observed in the germinated seeds.The model of essential amino acid was corresponding to the FAO recommend model, and the AAS,CS and EAAI showen increase at different level.Combined with efficiency ratio,the protein nutrition of soybean would be the most great under the 65 h,27℃and pH 7.5.Together,the data of this study probably provided the new information to improve the health of human beings.
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