Study On Extraction,Isolation,Purification,Component Analysis And Biological Activity Of Polyphenols From Millet

[Objective] In this study,the extraction,isolation and purification,component analysis and in vitro physiological activity of polyphenols in Shanxi millet were studied,and the purpose was to provide a theoretical basis for the in-depth study of millet polyphenols.[Methods](1)Cellulase and pectinase were used to extract millet polyphenols.The enzyme concentration,enzymolysis time,enzymolysis temperature,p H value were set as single factors,and response surface experiments were designed on the basis of single factors to obtain the best technological conditions for extracting millet polyphenols.At the same time,this method was used to compare with other methods.(2)Millet polyphenols were separated and purified with AB-8 macroporous resin,the static and dynamic adsorption and desorption kinetics were studied,and the adsorption amount,adsorption rate,desorption rate and elution rate were calculated.The chemical identification method,infrared spectroscopy,ultraviolet-visible spectroscopy,liquid chromatography-mass spectrometry(LC-MS)were used to analyze the components of the purified millet polyphenols,and the main polyphenol compounds in millet were preliminarily inferred.(3)The antioxidant activity of millet polyphenols in vitro were studied.The DPPH radical scavenging rate,hydroxyl radical scavenging rate,reducing power,iron ion complexation and total antioxidant capacity(T-AOC)of millet polyphenols before and after purification were measured.At the same time,the anti-oil oxidation of millet polyphenols was studied,and the anti-oil oxidation effects of millet polyphenols were evaluated based on the peroxide value,anisidine value and total oxidation value.The composition and content of fatty acids in peanut oil were analyzed by gas chromatography-mass spectrometry(GC-MS).(4)The hypoglycemic activity of millet polyphenols in vitro was studied.The inhibition rate of?-amylase and ?-glucosidase by millet polyphenols before and after purification were measured,and the glucose absorption capacity was measured.[Results](1)The optimal conditions for the extraction of millet polyphenols were: cellulase to pectinase ratio 7:3,enzyme concentration 1.1%,enzymolysis time 88 min,enzymatic hydrolysis temperature 58 ?,p H 3.0.Under these conditions,the millet polyphenols yield was(1.52±0.004)%.Compared with other methods,this method had the highest yield.(2)In the experiment of separation and purification of millet polyphenols with AB-8 macroporous resin and component analysis,the results showed that the adsorption amount was(12.70±0.95)mg/g,the adsorption rate was(42.1±0.98)%,the desorption rate was(80.63±0.73)% and the elution rate was(84.00±1.22)%.The purity of polyphenols was increased from 31.80% to 72.80% after purification.It was presumed that millet polyphenols may contain flavonoids,and the main compounds may be hydroxycaffeic acid,cyanidin-3-O-galactoside and p-coumaryl malate.(3)The antioxidant capacity was positive control> millet polyphenol purified product> millet polyphenol crude extract.Millet polyphenols and Vc had a better synergistic effect,the anti-oxidation effect of peanut oil was stronger than that of artificial antioxidants.At the same time,it can inhibit the conversion of unsaturated fatty acids to saturated fatty acids in peanut oil with an inhibition rate of 28.23%.(4)The purified millet polyphenols had a better inhibitory effect on ?-amylase,and the purified and crude extracts had lower inhibitory rates on ?-glucosidase.Millet polyphenols had a certain ability to absorb glucose,and the purified product was stronger than the crude extract.[Conclusion] The compound enzyme method was used to extract millet polyphenols with high yield and strong feasibility,and can be widely used in the extraction research of millet polyphenols.This study shows that the purified millet polyphenols had stronger physiological activity than crude extracts in anti-oxidation,anti-lipid oxidation and in vitro hypoglycemic activity,which can provide a certain theoretical basis for further in-depth study of millet polyphenols.