The Optimized Extraction Process Of The Active Substance In Mulberry Leaf Used Response Surface Methodology And Its Effect On Meat Quality Of Donkey

This paper mainly studied how to optimize the extraction process of mulberry leaf active substances and its effect on the edible quality of donkey meat by response surface methodology,aiming to provide theoretical basis and practical guidance for mulberry leaf extract as a natural antioxidant to improve donkey meat quality and improve economic benefits.Experiment 1:response surface methodology was used to optimize the extraction process of active substances from mulberry leaves.Fresh mulberry leaf samples were dried,crushed and dried to prepare mulberry leaf powder.Response surface methodology(RSM)was used to optimize the extraction process of active substances from mulberry leaves.The results showed that the highest extraction rate of flavonoids was 3.64%,and the best DPPH radical scavenging activity of mulberry leaf extract was 99.18%.The results showed that the optimal extraction conditions were ethanol concentration 54.75%,extraction time 17.61 min,solid-liquid ratio 1:30.24,extraction temperature 50.27?.The results showed that the extraction rate of flavonoids and DPPH radical scavenging activity were 3.62%and 99.12%,respectively.There was no significant difference between them(P=0.24).Experiment 2:effect of mulberry leaf extract on the edible quality of donkey meat.The mulberry leaf extract prepared by the best extraction process in Experiment 1 was selected as the additive.After slaughtering,the fresh donkey meat was ground up and then subjected to the following five treatments:0%mulberry leaf extract group(blank group,c),0.2%mulberry leaf extract addition group(low concentration,1),0.4%mulberry leaf extract addition group(medium concentration,m),0.6%high concentration mulberry leaf extract addition group(high concentration,H)and 0.05%VC addition group(VC)Tibet.During the cold storage period,samples were taken at 1D,3D,6D,9D to determine the relevant indicators.The results showed that the pH of donkey meat ranged from 5.35 to 5.63,which decreased first and then increased with time(P<0.01).The pH value of medium concentration mulberry leaf extract treatment group was the highest,and that of blank control group was the lowest(P<0.01).L*,a*and B*in donkey meat color decreased with time(P<0.01).Among the control groups,the highest values of L*,a*and B*were 36.16,15.2 and 7.90 respectively(P<0.01).The cooking loss of donkey meat was significantly affected by time(P<0.01),and the cooking loss of blank treatment group was the highest(P<0.01),and there was no significant difference between other treatment groups.In sensory evaluation,odor,tenderness,juiciness,flavor and liking degree()decreased with time(P<0.01),and there was no significant difference between the treatment groups.The activities of catalase(CAT),glutathione reductase(GSH),total antioxidant capacity(T-AOC)and superoxide dismutase(SOD)decreased with the prolongation of storage time.The content of malondialdehyde(MDA)increased with time(P<0.05).The low concentration treatment group had higher catalase(CAT)activity,glutathione reductase(GSH)activity,total antioxidant capacity(T-AOC),superoxide dismutase(SOD)activity,and lower malondialdehyde(MDA)content.Finally,mulberry leaf extract can slow down the pH decline rate of donkey meat,improve the color brightness of donkey meat,delay the decline of antioxidant enzyme activity,slow down the generation of oxidation products,and increase the shelf life of donkey meat.