Research Of Extraction And Antioxidant Activities Of Flavonoids From Gongcheng Green Persimmon Fruit

Persimmon(Diospyros kaki Thunb.), a centuries-old cultivated history tree, belongs to the D iospyros L.f genus, Ebenaceae Family. Persimmon is native to China and one of the five important fruits (grape, orange, banana, apple, persimmon) in China. Based on the summary of cultivated situation, nutritional and chemical compositions, bioactive substances of persimmons, as well as flavonoids and their antioxidant activities in recent years, more research focused on the tannin in persimmon and flavonoids in the leaf but the flavonoids in green persimmon fruit. In the paper, Gongcheng persimmon was chosed as raw material, the extraction, purification and antioxygenic property were studied which hopes to provide theoretical basis for processing of Gongcheng persimmon, maximize utilization and obtain the biggest economic benefits.The main results obtained from the experiments were as follows:1. Flavonoids were extracted from green persimmon fruit with technologies of traditionalreflux alcohol-extraction, ultrasonic-assisted extraction, microwave-assisted extraction and enzymatic hydrolysate. Results showed that ultrasonic-assisted extraction was the best extraction technology. The optimum extracting conditions were ultrasound power 90W, extracting time 30 min, ultrasonic temperature 75℃,alcohol volume fraction 40%, the mass ratio of material to alcohol 1:12 and. Under this condition, the yield was 4.52%(w/w).The optimum technologies for traditional reflux alcohol-extraction were alcohol volume fraction 40%, the mass ratio of material to alcohol 1:12, extracting temperature 70℃, extracting time 5 h and the yeild was 4.11%; the parameters were microwave power 700W, processing time 120s and the mass ratio of material to alcohol 1:10 for microwave-assisted extraction, the corresponding yeild was 3.74%; the parameters were enzyme content (cellulase/pectinase 1:1) 6mg, pH 3.5, hydrolysis time 3h hydrolysis temperature 50℃, alcohol volume fraction 40% and the mass ratio of material to alcohol 1:12 for enzymatic hydrolysate, the corresponding yeild was 4.02%.2. D101 resin was determined as macroporous adsorption resin according to the screening for a variety of resins. At the same time, the optimum technology was selected under the condition of amount of loaded sample 100mL, flow rate 1mL/min, concentration 0.8mg/mL, pH 5.0,80% ethanol solution as eluent with flow rate of 1mL/min and eluent dosage of 6BV, the purity of 53.8% was obtained. 3. Results showed that Total Antioxidant Capacity (TAC) and scavenging capacity for three kinds of free radicals were enhanced with increasing green persimmon fruit flavonoids content using Prussia orchid method. In addition, the biggest scavenging capacities for hydroxyl radical(·OH), DPPH free radical and super oxygen free radical (02--) were 32.4%,96% and 52.4% respectively.