| Kelp is a traditional Chinese medicine edible plants,has soft firm,the effect of water,kelp in the process of growth and metabolism of accumulated a large number of secondary metabolites such as phenols,polysaccharide,their effects on organism and the human body has important physiological regulation and control function.So far,both at home and abroad,the reports on the study of laminarin are more,and the research progress of kelp polyphenols are rarely reported.This paper studies kelp polyphenols extraction method,antioxidant activity in vitro and bacteriostatic activity,providing the basis for deep development of kelp,laying a theoretical foundation for high added value of kelp and use.This paper use ethanol extraction,supersonic-assisted and MAE method to extract the kelp polyphenols,and of the three kinds of single factor tests and response surface optimization respectively,after discussion to determine the best extraction process and the process parameters.From the crude extract of kelp polyphenols and purification,for in vitro antioxidant and antibacterial activity test,the measured results of its physiological activity is of great guide for the comprehensive utilization of kelp.The main research content as follows:?1?Respectively using ethanol extraction,supersonic-assisted and MAE method to extract kelp polyphenols,single factor tests and response surface optimization,to determine the optimum process conditions of the extraction of kelp polyphenols as: 1)ethanol extraction,ethanol concentration 35%,ratio of liquid to solid 40:1?m L/g?,water bath time 50 min,water bath temperature 70 ?,the yield of kelp polyphenols average of 2.966 mg/5g;2)Ultrasonic assisted extraction,ethanol concentration 30%,ratio of liquid to solid 40:1?mL/g?,ultrasonic time 32 min?m L/g?,,ultrasonic temperature 35 ?,the yield of kelp polyphenols average of 4.485 mg/5g;3)Microwave assisted extraction,ethanol concentration 30%,ratio of liquid to solid 35:1?mL/g?,microwave power 450 W,microwave time 100 s,the yield of kelp polyphenols average of 8.952 mg/5g.In conclusion,microwave assisted extraction method is more suitable for a large number of kelp polyphenols extracted to functional test and research.?2?The crude extract of kelp polyphenols was purified by four times of alcohol precipitation,and the content of 38.7% was obtained.The antioxidant and scavenging free radical scavenging ability of the extract of kelp polyphenols were studied.By DPPH ·,· OH and O2-?,free radicals as the research object,by tea polyphenols?content of 40%?and VC contrast to analysis and comparison of kelp polyphenols antioxidant activity in vitro.,Results show that,by measuring IC50 could discern the DPPH radical scavenging ability: tea polyphenols > kelp polyphenols > VC;For ?OH radical scavenging ability: tea polyphenols > kelp polyphenols > VC;Of O2-? radical scavenging ability: VC > kelp polyphenols > tea polyphenols.?3?Kelp polyphenols extract of content of 38.7% antibacterial activity test,select bacillus subtilis,e.coli,staphylococcus aureus,and the four kinds of wine yeast fungus,determine the minimum bacteriostasis concentration.A ccording to the results,The minimum inhibitory concentrations of keip polyphenol extract on bacillus subtilis,staphylococcus aureus,e.coli,and wine yeast fungus were 1.25 mg / mL,1.25 mg / mL,2.5mg / m L and 5mg / m L,respectively.?4?The effects of pH value and temperature on the antibacterial activity of kelp polyphenol extract on bacillus subtilis,e.coli,staphylococcus aureus,and wine yeast fungus were studied.The results showed that the antimicrobial activity of kelp polyphenols was different with the pH value of the culture medium,when the pH value was between 7 and 8,the antibacterial activity was the strongest;With the increase of culture temperature,there was no significant difference in the diameter of the inhibition zone of yeast,indicating that the thermal stability of the antimicrobial activity of the extract of kumugol was better. |
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