[ Objectivel The aim was to determine the optimal technology for ultrasonic-assisted extraction of black tea was determined. [ Methed] Taking Black Tea as materials, the Box-Behnken response surface design method of t...[ Objectivel The aim was to determine the optimal technology for ultrasonic-assisted extraction of black tea was determined. [ Methed] Taking Black Tea as materials, the Box-Behnken response surface design method of tea polyphenols ultrasonic-assisted extraction process optimi- zation was applied. The regression optimization model of the ethanol volume fraction, ultrasonic time, and ultrasonic temperature, ethyl acetate extract stalling time and tea polyphenols was established. [ Result] The influence of four factors on the black tea polyphenol solvents affecting size was as follows： ultrasonic time 〉 ethanol volume fraction 〉 stalling extraction time 〉 ultrasound temperature. The best extraction process was ultrasonic time 80 min, volume fraction of 88.99% ethanol, extraction time 89.97 min, ultrasonic temperature of 80℃. At the optimized technical parameters, the black tea phenolic extraction yield can be as high as 73.50%. [ Conclusion] The study provided theoretical basis for the development of tea leaves and black tea.展开更多
Ethylene glycol monoethyl ether acetate (EGEA), an excellent solvent, is prepared with ethylene oxide (EO) and ethyl acetate (EA) in a tubular reactor under suitable reaction condition. The single circulation yield ca...Ethylene glycol monoethyl ether acetate (EGEA), an excellent solvent, is prepared with ethylene oxide (EO) and ethyl acetate (EA) in a tubular reactor under suitable reaction condition. The single circulation yield can reach 81%. This technology is not only safe but also makes it possible to continuously produce EGEA in industry,with low content of high boiling point by-products.展开更多
This study evaluated the effect of four different solvent, i.e., water, ethanol, water-ethanol mixture and ethyl acetate, on the antioxidant activities of wild and cultivated heather （Calluna vulgaris （L.） Hull） p...This study evaluated the effect of four different solvent, i.e., water, ethanol, water-ethanol mixture and ethyl acetate, on the antioxidant activities of wild and cultivated heather （Calluna vulgaris （L.） Hull） plant. The highest values for total flavonoid content were obtained for samples extracted using ethanol-water mixture and ethyl acetate. Cupric reducing antioxidant capacity （CUPRAC） method, scavenging ability on 1,1-diphenyl-2-pirylhydrazyl radicals （DPPH） radicals and chelating activity on Fe2~ ions have been used for evaluation of antioxidant activity of the extracts. Ethanolic fraction exhibited the lowest reducing capacity, despite a heather sample used. The extracts of cultivated heather exhibited significant scavenging effect on DPPH radicals, and ethanol and ethanol-water fractions were found to be the most effective. The metal-chelating effect of the extracts increased in the order： ethanol 〈 ethyl acetate 〈 ethanol-water 〈 water. The results may be helpful for better utilization of heather flowers extracts as potential pharmaceutical and nutraceutical ingredient.展开更多
文摘[ Objectivel The aim was to determine the optimal technology for ultrasonic-assisted extraction of black tea was determined. [ Methed] Taking Black Tea as materials, the Box-Behnken response surface design method of tea polyphenols ultrasonic-assisted extraction process optimi- zation was applied. The regression optimization model of the ethanol volume fraction, ultrasonic time, and ultrasonic temperature, ethyl acetate extract stalling time and tea polyphenols was established. [ Result] The influence of four factors on the black tea polyphenol solvents affecting size was as follows： ultrasonic time 〉 ethanol volume fraction 〉 stalling extraction time 〉 ultrasound temperature. The best extraction process was ultrasonic time 80 min, volume fraction of 88.99% ethanol, extraction time 89.97 min, ultrasonic temperature of 80℃. At the optimized technical parameters, the black tea phenolic extraction yield can be as high as 73.50%. [ Conclusion] The study provided theoretical basis for the development of tea leaves and black tea.
文摘Ethylene glycol monoethyl ether acetate (EGEA), an excellent solvent, is prepared with ethylene oxide (EO) and ethyl acetate (EA) in a tubular reactor under suitable reaction condition. The single circulation yield can reach 81%. This technology is not only safe but also makes it possible to continuously produce EGEA in industry,with low content of high boiling point by-products.
文摘This study evaluated the effect of four different solvent, i.e., water, ethanol, water-ethanol mixture and ethyl acetate, on the antioxidant activities of wild and cultivated heather （Calluna vulgaris （L.） Hull） plant. The highest values for total flavonoid content were obtained for samples extracted using ethanol-water mixture and ethyl acetate. Cupric reducing antioxidant capacity （CUPRAC） method, scavenging ability on 1,1-diphenyl-2-pirylhydrazyl radicals （DPPH） radicals and chelating activity on Fe2~ ions have been used for evaluation of antioxidant activity of the extracts. Ethanolic fraction exhibited the lowest reducing capacity, despite a heather sample used. The extracts of cultivated heather exhibited significant scavenging effect on DPPH radicals, and ethanol and ethanol-water fractions were found to be the most effective. The metal-chelating effect of the extracts increased in the order： ethanol 〈 ethyl acetate 〈 ethanol-water 〈 water. The results may be helpful for better utilization of heather flowers extracts as potential pharmaceutical and nutraceutical ingredient.
