Preparation Of Stropharia Rugoso-annulata Peptide And Preliminary Study On Its Antioxidant Activity And Immune Activity

Stropharia rugoso-annulata,as a high-end and high-quality edible mushroom,has advantages such as fast growth rate,high yield,and strong adaptability.In recent years,its planting scale in China has been continuously expanding.However,grass rot fungi have a high moisture content and are prone to opening umbrellas,spoilage,and loss of commercial value.The protein content of Stropharia rugoso-annulata is between 25%-35%,containing 8 essential amino acids for the human body.The nutritional value evaluation is similar to the reference protein model proposed by FAO/WHO.With the development of the Stropharia rugoso-annulata planting industry,it is necessary to vigorously develop the deep processing industry to improve the utilization and added value of Stropharia rugoso-annulata.In view of this,this experiment mainly develops the protein of Stropharia rugoso-annulata,prepares small molecule bioactive peptides of Stropharia rugoso-annulata,and explores the antioxidant and immune activities of Stropharia rugoso-annulata peptides.1.The ultrasonic assisted alkaline extraction method was used to study the extraction process of Stropharia rugoso-annulata protein.The results showed that the optimal process parameters for alkaline extraction of Stropharia rugoso-annulata protein were: material liquid ratio 1:30,p H value 11,alkaline extraction temperature 65℃,alkaline extraction time 90 minutes,centrifugation to extract the supernatant,and continued ultrasonic assisted alkaline extraction of the waste.Under the conditions of material liquid ratio 1:30,ultrasonic time 20 minutes,ultrasonic temperature 50 ℃,ultrasonic p H 10,and ultrasonic power 200 W,The protein extraction rate is 51.09%,which is 5.11% higher than alkaline extraction.Finally,Stropharia rugoso-annulata protein was separated by isoelectric precipitation(with a p I of 3.8)and salting out(with an ammonium sulfate saturation of 50%),and freeze-dried to obtain protein freeze-dried powder.2.Using the hydrolysis degree of Stropharia rugoso-annulata protease hydrolysate as a reference index,study the effect of dual enzyme synchronous enzymatic hydrolysis on the hydrolysis degree of Stropharia rugoso-annulata protease hydrolysate.The optimal process parameters for enzymatic hydrolysis of Stropharia rugoso-annulata were obtained through single factor and response surface optimization: p H value of 7.8,temperature of 48 ℃,substrate concentration of 3.8%,enzyme dosage of 11000 U,enzymatic hydrolysis time of 6 hours.Finally,the hydrolysis degree of Stropharia rugoso-annulata enzymatic hydrolysis solution reached 67.3%.3.The enzymatic hydrolysate of Stropharia rugoso-annulata was separated,purified and freeze-dried by ultrafiltration and gel chromatography,and the antioxidant activity and immune activity of each component were preliminarily evaluated in vitro.The results indicate that:(1)The enzymatic hydrolysates and various ultrafiltration components all exhibit antioxidant activity,among which the enzymatic hydrolysates exhibit the strongest DPPH free radical scavenging rate and 3-10 k Da exhibit the strongest hydroxyl free radical scavenging rate;< 3 k Da exhibited the strongest ABTS radical scavenging rate and metal chelating ability;The enzymatic hydrolysis products and<3 k Da showed the strongest total reducing power;F1 in each component of gel filtration showed the strongest DPPH radical scavenging rate and total reducing power;The F2 component exhibits the strongest hydroxyl radical scavenging rate and metal chelating ability;Both F2 and F1 showed the strongest ABTS radical scavenging rate.(2)The enzymatic digestion products and fractions of Stropharia rugoso-annulata promoted the proliferation of RAW 264.7 cells,with the <3 k Da fraction showing the highest relative proliferation rate,and also promoted the phagocytosis of neutral red and the secretion of NO in RAW 264.7 cells.The F2 fraction had the highest relative proliferation rate after gel filtration;the F1 fraction had the strongest ability to promote phagocytosis of neutral red;the F2 fraction had the strongest ability to promote NO secretion by the cells.