Preparation Of Echinacea Juice Rich In Caffeic Acid Derivatives

Fresh Echinacea is rich in caffeic acid derivative(CADs),but polyphenol oxidase(PPO)easily degrades CADs and reduces its immune-enhancing effect.In this paper,the properties of PPO enzymes in different parts of Echinacea were studied,and determined the suitable passivation method to maximize the retention of CADs,and developed the healthy juice of Echinacea rich in CADs.The results were as follows:(1)The traditional heat treatment could passivate the activity of PPO to increase the retention of CADs,while the retention in different parts of Echinacea(root,stem,leaf and flower)was different under the same high temperature steam treatment.Taking fresh Echinacea flowers as an example,the PPO was passivated by the traditional heat treatment(blanching,high-temperature steam,and medium-temperature drying),and the retention of chlorogenic acid and chicinic acid in Echinacea flowers was significantly increased as compared with the non-passivated ones,especially high-temperature steam heat treatment.After 15 min high temperature steam treatment at 100~oC for 15 min,the activity of PPO enzyme in year stubble flowers decreased to12.74%,while the contents of chlorogenic acid and cichoric acid increased by 7.85 and46.29 times,respectively.The contents of chlorogenic acid and cichoric acid in the roots,stems,leaves and flowers of Echinacea were increased(1.84 to 2.75 times)by high temperature steam(100~oC,15 min)than those of the non-passivated ones,but showed regional characteristics,speculating that it was related to the different configuration or properties of PPO enzyme at different sites.(2)There were differences in the properties of PPO enzymes among the flowers,leaves and roots of Echinacea,and the effect of high temperature steam passivation on the leaves of Echinacea was better than that of citric acid and high temperature steam treatment.With the prolongation of time,the crude enzyme of PPO in flowers,leaves and roots of Echinacea was placed at 100~oC,the activity of PPO decreased gradually.The pH reaction in the root of Echinacea showed several different optimum intervals,and the optimum PPO reaction in leaves of Echinacea was the highest in pH7.5,but was lower in acid condition than that in Echinacea leaves.According to the difference of PPO enzyme properties,high-temperature steam treated with dull enzyme or organic acid combined with high-temperature steam was selected respectively.The results showed that the relative enzyme activity of PPO could be reduced to 6.82%when Echinacea was treated with high-temperature steam for 25min.The relative enzyme activity of PPO in Echinacea leaves was reduced to 10.94%when citric acid solution with pH 3.5 was used in cooperation with high-temperature steam treatment for 15 min.Besides,the total CADs content was retained at 6.65 mg/g,which was 2.26 times higher than that without treatment.(3)The health care juice of Echinacea rich in CADs was prepared.The preparation methods of the CADs-rich Echinacea juice were as follows:the flowers were treated with steam at high temperature for 25 min,then juicing with water,ultrasonic treatment with 250 W for 5 min,centrifugal removal of filter residue,pasteurization and bagging.The dissolution amount of CADs was 1.10 mg/mL,and the dissolution rate was 78.01%;the leaves were processed by high-temperature steam for15 min,then juicated with citric acid solution with a pH of 3.5,then treated with 300 W ultrasound for 5 min,centrifuged to remove filter residue,and bagged after pasteurization.The dissolution amount of CADs was 0.92 mg/mL and the dissolution rate was 69.70%.(4)Echinacea juice had significant effect on delayed allergy and improved immune function of mice.An example of delayed type allergy in mice was used to verify the immunoenhancement effect of Echinacea sinense juice.The effect of leaf juice in the high-dose group(6.25 mg/kg)and flower juice in the high-dose group(6.25 mg/kg)on DTH was better than that in the positive control group(p<0.05),and the ear difference of the mice were(13.97±2.02)mg and(14.85±1.97)mg,which were 94.30%and106.54%higher than that in the positive group(7.19±2.15)mg,respectively.