Study On Preparation Technology And The Activity Of Polypeptide From Pleurotus Eryngii In Vitro

Polypeptide can effectively reduce the damage of free radicals to human body,and thus delaying human aging and reducing the probability of human diseases,due to its strong antioxidant,antibacterial and other biological activities.However,the content of polypeptide produced by human body is too little to offset the damage of free radical to human cells.Therefore,it is necessary to synthesize or extract polypeptides artificially.But the technology of synthetic or extract peptide is complex,low extraction efficiency,high cost,so this paper puts forward with using pleurotus eryngii stalks which has more protein and low price as raw materials.Polypeptides were extracted by enzymolysis of proteins and their antioxidant activities were studied in vitro.At the same time,the antibacterial and anti-alcoholism activities of polypeptides in vitro were studied.Finally,a high efficient and low cost bioactive peptide preparation and technology were obtained.It realized the purpose of "turning waste into treasure" and reducing the cost of polypeptide producing.The main research results are as follows:(1)Extraction of pleurotus eryngii proteinThe ultrasonic assisted extraction of pleurotus eryngii protein inwas studied.The results showed that the factors affecting the extraction rate of pleurotus eryngii protein were in the following order: extraction times > extraction pH > extraction time > water-material ratio.The optimal technological parameters obtained by orthogonal experimental analysis are: extraction times is 2,extraction pH is 11,water-material ratio is 20:1,and extraction time is 1h.The results showed that the extraction rate can reach 45.1 % at the optimal technological(2)Preparation of polypeptides from pleurotus eryngiiThe effect of factors for enzymatic hydrolysis of pleurotus eryngii protein was studied.The factors affecting the polypeptide yield of pleurotus eryngii.were in the following order: enzymatic hydrolysis temperature > enzymatic hydrolysis pH > amount of enzyme > enzymatic hydrolysis time.The optimal technological parameters obtained by orthogonal experimental analysis are: the enzymolysis pH is 6.5,the enzymolysis temperature is 50℃,the amount of enzyme is 5000 U/g,the enzymolysis time is 4 hour,.The peptide yield can reach 43.8% at the optimal technological.(3)Antioxidant activity of polypeptides from pleurotus eryngii in vitroThe antioxidant activities about three kinds of pleurotus eryngii polypeptides with molecular weight below 1KD,between 1KD and 5KD and between 5KD and 10 KD in vitro showed that all three kinds of pleurotus eryngii polypeptides had antioxidant capacity.The polypeptide solution of pleurotus eryngii with molecular weight between 1KD and 5KD had the strongest scavenging ability of DPPH free radical and OH free radical,namely the strongest antioxidant capacity,and its antioxidant activity increased with the increase of concentration.Meanwhile,the DPPH radical scavenging ability of polypeptide solution of pleurotus eryngii with molecular weight between 1KD and 5KD was higher than that of hydroxyl radical scavenging ability.(4)Preliminary study on antibacterial activity of polypeptides from pleurotus eryngii in vitroThe antimicrobial activity of polypeptide solutions with molecular weight below 1kd-5kd and 1KD was tested in vitro.The results showed that the polypeptide solutions with molecular weight below 1KD had no obvious antibacterial effect on escherichia coli,staphylococcus aureus,salmonella and bacillus subtilis in the concentration range of the experiment.The polypeptide solution of pleurotus eryngii with molecular weight between 1KD and 5KD had obvious bacteriostatic effect on esherichia coli and bacillus subtilis,but had no obvious bacteriostatic effect on staphylococcus aureus and salmonella.(5)Preliminary study on anti-alcoholism activity of pleurotus eryngii in vitroPreliminary study on anti-alcoholism activity in vitro of polypeptides from pleuromus eryngii showed that three kinds of polypeptides with molecular weight below 1KD,between 1KD and 5KD and between 5KD and 10 KD had certain anti-alcoholism activity in vitro.According to the experimental data,the anti-alcoholism activity is related to the molecular weight.Among them,the anti-alcoholism activity in vitro about polypeptides of pleurotus eryngii with molecular weight below 1KD was significantly higher than that of other two kinds of pleurotus eryngii polypeptides.