Preparation And Activity Study Of Peptides From Imperial Chrysanthemum

Imperial Chrysanthemun is an important plant flower that integrates ornamental value and drinking nutritional value.However,at present,there are only a few related products.They are mainly sold as fresh flowers for ornamental use and brewed drinks for drying.The added value is low,and the appearance is not perfect.Processes such as drying and processing are prone to generate a large amount of residual waste,resulting in waste of resources.The protein of Imperial Chrysanthemun has high protein content and rich amino acid composition.It is an excellent source of protein polypeptides,but it is difficult to give full play to its nutritional and health care effects by direct consumption or hot water brewing.The goal of this thesis is to obtain the polypeptide of Imperial Chrysanthemun by enzymatic hydrolysis of Imperial Chrysanthemun protein,research and develop its function and potential use,and further improve the added value of Imperial Chrysanthemun.In this study,the dried flowers of Imperial Chrysanthemun were used as raw materials,and the protein of Imperial Chrysanthemun was extracted by grinding,alkali dissolution and acid precipitation.Then three different enzymatic hydrolysis methods were used for enzymatic hydrolysis of the above proteins: synergistic enzymatic hydrolysis using flavor protease and papain,step-by-step enzymatic hydrolysis using flavor protease first and then using papain,step-by-step enzymatic hydrolysis using papain first and then using flavor protease,respectively.Three samples of enzymolysis peptides were obtained,in order of synergistic enzymolysis product(XTPH),step-by-step enzymolysis product using flavor protease first and then papain(FMPH),first using papain and then using flavor protease step-by-step enzymolysis product(MFPH).After activity screening,it was found that the above three enzymatic peptides have a certain degree of α-glucosidase inhibitory activity,and the α-glucosidase inhibitory activity of FMPH is better.In order to further search and confirm the components with α-glucosidase inhibitory activity in the above-mentioned polypeptide products,three different enzymatic hydrolysis products were separated by ultrafiltration centrifugation.After preliminary screening,the research focus was on the components with molecular weight less than 3000,three samples were obtained: FMPH-1,MFPH-1,XTPH-1,and the structural changes were characterized by Fourier transform infrared spectrometer and fluorescence spectrophotometer.At the same time,the activity test results showed that the FMPH-1 isolated from FMPH had strong α-glucosidase inhibitory activity.The main component of the polypeptide sample was determined by LC-MS to be a polypeptide composed of 4-5 amino acids.In addition,two samples of chrysanthemum protein and FMPH-1 were selected for gastrointestinal digestion simulation in vitro.The experimental results showed that the α-glucosidase inhibitory activity of the sample after FMPH-1 digestion simulation(FMY-1)was further improved,it is suggested that the enzymatically hydrolyzed polypeptide of Imperial Chrysanthemun has better functional properties in vivo than the protein of Imperial Chrysanthemun.Next,the enzymatic hydrolysis preparation process of FMPH was optimized.On the basis of single factor and orthogonal experiments,the optimal process conditions were obtained through response surface optimization: the enzyme dosage was 11800 U/g,the ratio of flavor enzyme to papain enzyme activity was 1:1,the substrate concentration is1.50%,and the degree of hydrolysis reaches 22.57% under this condition.To sum up,in this study,the protein was extracted from Imperial Chrysanthemun,and different enzymatic hydrolysis methods were used to prepare the enzymatic hydrolyzed polypeptide of Imperial Chrysanthemun.The FMPH-1 component of α-glucosidase inhibitory activity and its preliminary structure were studied.In vitro gastrointestinal digestion simulation experiments show that the enzymatic peptides have better in vivo activity compared with the unenzymatically hydrolyzed Imperial Chrysanthemun protein.Finally,the optimal enzymatic hydrolysis conditions of FMPH were obtained through process optimization,which laid a foundation for further research and development of the polypeptide of Imperial Chrysanthemun.