Preparation And Antioxidant Activities Of Mushroom(Lentinus Edodes) Peptides

Mushrooms(Lentinus edodes)are rich in nutrients,especially polysaccharides,proteins and amino acids.Mushroom root is a byproduct of production process which generally accounts for 20%to 30%of the total weight.However,because of its high content of fibers and poor palatability,mushroom roots usually are discarded during the treatment.Long-term excessive alcohol consumption leads to alcoholic liver disease(ALD).In China,ALD incidence rate showed a gradual upward trend,and in some areas even has become the second leading cause of liver damage.Till now,the studies on mushrooms are limited to polysaccharides extraction,activity research,and mushroom drinks,while few researches are reported about using mushroom roots to prepare peptides and investigate its biological activities.This study aimed to compare differences of protein contents and total antioxidant capacities between the mushroom umbrella powder,mushrooms roots powder and whole mushroom powder,determining whether the development and utilization of mushrooms roots is feasible,which can achieve turning waste into treasure and cater to the trend of forest economy.Ultrasonic assisted cellulose hydrolysis was employed to break the cell wall of mushrooms.Besides,ammonium sulfate precipitation was also used to improve the protein dissolution rate.We compared the degree of hydrolysis and DPPH radical scavenging capability of three different mushroom powder sources after hydrolyzed by Papain,Alcalase,Trypsin and Protamex.Considering the results,appropriate enzymes was selected to finish single factor experiments and orthogonal optimization test to obtain mushrooms peptides.Furthermore,the antioxidant capacity and activation effects on alcohol dehydrogenase and aldehyde dehydrogenase:in vitro of the obtained mushrooms peptides were also investigated to verify its potential function on facilitating alcohol metabolism.The results showed that although mushroom root powder had the lowest protein content than those of mushroom umbrella powder and whole mushroom powder,the peptide made by mushroom roots was obtained with the highest of DPPH radical scavenging capability after enzymatic hydrolysis.This conclusion proved the feasibility and value of utilizing mushrooms roots.In this study,the following conclusions were obtained:(1)The optimal conditions for the preparation of mushroom peptides was:mushroom root powder was dealt with Protamex at a pH value of 6.0,temperature of 50?,[E]/[S]of 0.20%and the hydrolyzing time of 3 h.Under this condition,the amino content in the enzymatic hydrolysis liquid reached 29.23%.(2)Mushroom peptides had the ability to scavenge DPPH·with an IC50 of 0.152 mg/mL.Besides,it also had a good ability to inhibit OH,of which the IC50 was 0.190 mg/mL.(3)Mushroom peptides with a molecular weight range of 5-10 kD were confirmed to have the strongest activity of activating alcohol dehydrogenase(with an activating rate of 94.58%±0.74%at the concentration of 30 mg/mL)and acetaldehyde dehydrogenase(70.69%± 1.25%at the concentration of 180 mg/mL).(4)Mushroom peptides were preliminarily separated and purified through gel filtration chromatography,of which the suitable separation conditions was:Sephadex G50,50mmoL/L of Tris-HCl(pH 7.1),0.3 mL/min of flow rate,and 5 mL of injection volume.The peptides were divided into four fractions according to the molecular size,among which the total antioxidant capacity of Fraction 3 was the best.This study indicated that mushroom(Lentinus edodes)peptides had strong antioxidant capacity and potential function on facilitating alcohol metabolism,suggesting the feasibility of deep and broad development and application.