CN1088053C

CN1088053C - Method for extracting tea-polyphenol from tea

Info

Publication number: CN1088053C
Application number: CN98111572A
Authority: CN
Inventors: 王洪新; 张家骊; 吕源玲
Original assignee: WUXI LIGHT INDUSTRY UNIV
Current assignee: WUXI LIGHT INDUSTRY UNIV
Priority date: 1998-11-12
Filing date: 1998-11-12
Publication date: 2002-07-24
Anticipated expiration: 2018-11-12
Also published as: CN1253940A

Abstract

The present invention provides a method of preparing tea polyphenol from tea leaves, which comprises: leaching tea leaves with hot water or ethanol solution, separating and concentrating tea extract in vacuum to obtain concentrated tea extract, separating caffeine by supercritical carbon dioxide extraction, concentrating and drying residual tea extract vacuum to obtain tea polyphenol. In order to enhance the purity of the tea polyphenol, extracting the residual tea extract with an ethyl acetate solvent to obtain tea polyphenol, concentrating and drying the tea polyphenol in vacuum to obtain tea polyphenol powder, and removing the residual solvent by supercritical carbon dioxide extraction to obtain refined tea polyphenol powder. The tea polyphenol products are suitable for different occasions, low in the caffeine content and free of residual solvent.

Description

From tealeaves, produce the method for tea-polyphenol

The present invention relates to from tealeaves, produce the method for tea-polyphenol.

Natural polyphenol material-the tea-polyphenol that extracts from tealeaves has been classified national standard as, as antioxidant from natural food.At present, from tealeaves, extract the method for tea-polyphenol, mainly contain following three kinds: one, with water-containing organic solvent extraction-chloroform caffein-free and pigment-ethyl acetate extraction: two, with water extraction-organic solvent extraction-concentrate drying; Three, with organic solvent extraction-heavy metallic salt precipitation-acid molten-organic solvent extraction-concentrate drying.Such as disclosed extracting method such as the clear 59-219384 of day disclosure special permission communique, clear 61-13085 and Chinese patent specification sheets CN1043730A, be not always the case.The main drawback of said extracted method is: 1, use multiple organic solvent, step is complicated, heat often, and the production cost height, Determination of Residual Organic Solvents is higher in the finished product; 2, use is made precipitation agent to the deleterious heavy metal of human body (as mantoquita or lead salt); 3, cause environmental pollution with strong acid and strong base.

The object of the present invention is to provide the another kind of method of from tealeaves, extracting tea-polyphenol, when this kind method adopts extraction process to extract tea-polyphenol, use less organic solvent, avoid the strong acid and strong base that uses toxic heavy metal and be harmful to environment, have good extraction homogeneity and extraction efficiency, content of caffeine is low in the tea-polyphenol that obtains, and does not contain residual solvent.

The method of the present invention ethanolic soln backflow lixiviate of broken tea through 60-100 ° hot water or 20-80%, broken tea and hot water or aqueous ethanolic solution were by weight 1: 8 proportioning, after lixiviate 20-90 minute, tealeaf residue is removed in press filtration, get tea juice, through vacuum concentration, generally be concentrated into 1/3 of original volume, obtain concentrated tea juice I; Said concentrated tea juice I is put into the supercritical carbon dioxide extraction still, use supercritical carbon dioxide extraction, keep extraction kettle pressure 250-350 crust, temperature 30-70 ℃, keep separating still pressure 30-80 crust, temperature 30-60 ℃, extract the separation caffeine 4-10 hour, take out raffinate tea juice and carry out vacuum concentration, obtain concentrated tea juice II, make yellowish or green tea-polyphenol through vacuum-drying, this is the tea-polyphenol that contains low-caffeine.Isolated caffeine is as byproduct.The technical process of present method is expressed in the accompanying drawing 1.

As the tea-polyphenol that requires to make has higher purity, the present invention takes following additional method to improve its purity, and the concentrated tea juice II in the preceding method with ethyl acetate extraction at least twice, is extracted tea-polyphenol, the combined ethyl acetate phase makes tea-polyphenol through concentrating under reduced pressure and vacuum-drying.For further improving purity, the tea-polyphenol that above-mentioned addition method makes is put into the supercritical carbon dioxide extraction still, use supercritical carbon dioxide extraction, keep extraction kettle pressure 200-300 crust, temperature 30-70 ℃, keep separating still pressure 30-80 crust, temperature 30-60 ℃, extracted 2-5 hour, slough residual solvent.The aforementioned technical process of producing the method for tea-polyphenol and improving the addition method of its purity is expressed among Fig. 2:

Last supercritical carbon dioxide extraction removes the operation of residual solvent among Fig. 2, if necessary, also can directly be additional among Fig. 1 backmost, is used for thick tea-polyphenol and removes residual solvent (for example broken tea is with acetate ethanolic soln backflow lixiviate).

The technical process that above-mentioned Fig. 1 expresses is the basic technology of the inventive method.Additional ethyl acetate extraction technology of Fig. 2 or supercritical co remove the technology of residual solvent, can choose according to the application requiring to tea-polyphenol goods purity, reach the rational ratio of performance to price.

In the technical process that Fig. 1 and Fig. 2 express, supercritical carbon dioxide extraction operation wherein, carbonic acid gas uses under the super critical condition state, its consumption technology is routinely chosen, use conventional or known supercritical carbon dioxide extraction apparatus, use through the carbonic acid gas recirculation of after separating: the separation in the method for the present invention, concentrate, operations such as drying and ethyl acetate extraction adopt conventional or known processing condition and device.

The inventive method with broken tea by lixiviate, separation, enrichment process, obtain containing the concentrated tea juice I of tea-polyphenol and caffeine, adopt supercritical carbon dioxide extraction separation caffeine wherein again, obtain concentrated tea juice II, vacuum-drying or additional ethyl acetate extraction final vacuum drying obtain tea-polyphenol again.The inventive method use toxic organic solvent less, production cost reduces, and is little to environmental influence.After tealeaf residue is separated, adopt supercritical co and organic solvent (ethyl acetate) extraction again, prevented tealeaf residue from autoclave, luming and caused in the ununiformity of the cross-sectional direction of autoclave and short transverse extraction and the phenomenon of extraction cycle lengthening, though can improve this undesirable condition by the structure of improving autoclave, but this has not only improved equipment manufacturing cost, and the extraction homogeneity can not show a candle to the technology that the inventive method adopts.Therefore, the inventive method can improve homogeneity, the extraction efficiency of extraction, shortens extraction cycle.Its technique effect compared with prior art has obvious improvement.

The inventive method will be through the powdery tea-polyphenol that obtains after supercritical carbon dioxide extraction (separation caffeine) and ethyl acetate extraction (extraction tea-polyphenol) technology, remove residual solvent through supercritical carbon dioxide extraction again, the content of caffeine that the finished product are comprised is extremely low, and do not contain residual solvent, make high-grade tea-polyphenol elaboration thus, this is the another outstanding substantive distinguishing features of the inventive method.

Fig. 1 is the process flow sheet that the inventive method is produced thick tea-polyphenol.

Fig. 2 is the process flow sheet that the inventive method is produced smart tea-polyphenol.

The embodiment of the inventive method below is described:

Example 1: the 250g broken tea is added 2000 milliliters of 100 ℃ of boiling water, lixiviate 45 minutes, press filtration gets tea juice, vacuum concentration is put into supercritical extraction reactor through supercritical carbon dioxide extraction to 640g tea juice, the flow 4-6 kilogram of carbonic acid gas/hour, keep extraction kettle pressure 250-260 crust, temperature 50-60 ℃, separating still pressure 40-60 crust, temperature 40-50 ℃, extracted 9 hours, take out raffinate, concentrate vacuum-drying, make thick tea-polyphenol 65g, yield 26% wherein contains tea-polyphenol 45.3%, caffeine 1.25%.In addition thick caffeine 2.2g, wherein contain caffeine 1.26g, content of caffeine 57.3%.

Example 2: 2009 broken teas are added 1600 milliliters of 100 ℃ of boiling water, lixiviate 45 minutes, press filtration gets tea juice, vacuum concentration is to 700g tea juice, put into supercritical extraction reactor through supercritical carbon dioxide extraction, the flow of carbonic acid gas keeps extraction kettle pressure 280-290 crust with example 1, temperature 60-70 ℃, separating still pressure 60-80 crust, extracted 6 hours by temperature 50-60 ℃, take out raffinate, concentrate tea juice 478.9g, extract three times with ethyl acetate (its with the volume ratio of tea juice 1: 1), get ethyl acetate phase solution through separatory, concentrating under reduced pressure, vacuum-drying gets tea-polyphenol, and tea-polyphenol is again through supercritical carbon dioxide extraction, and carbon dioxide flow is the same, extraction conditions is: extraction kettle pressure 220-240 crust, and temperature is 60-70 ℃; Separating still pressure 30-50 crust, temperature 30-40 ℃, extracted 4 hours, get 23.95 gram tea-polyphenol, yield 11.98%, wherein polyphenol content 95.78%, content of caffeine 1.37%.Product gas chromatography determination, organic solvent residual are zero.Get thick caffeine 4.36g in addition, wherein contain caffeine 3.06g, content of caffeine 70.2%.

Example 3: the 200g broken tea was refluxed 1 hour with 2000 milliliter of 70% ethanolic soln, filtering and concentrating gets tea juice 715g, get 310g tea juice, be equivalent to tealeaves 86.71g, put into supercritical extraction reactor through supercritical carbon dioxide extraction, carbon dioxide flow keeps extraction kettle pressure 320-330 crust with example 1, temperature 40-50 ℃, separating still pressure 50-70 crust, extracted 5 hours by temperature 40-50 ℃, take out raffinate, concentrate tea juice 162g, extract three times with ethyl acetate (its with the volume ratio of tea juice 1: 1), get ethyl acetate phase solution through separatory, concentrating under reduced pressure, vacuum-drying gets tea-polyphenol, and tea-polyphenol is again through supercritical carbon dioxide extraction, and carbon dioxide flow is the same, extraction conditions is: extraction kettle pressure 280-300 crust, temperature 50-60 ℃; Separating still pressure 60-80 crust, temperature 40-50 ℃, extracted 2 hours, get the green powdery tea-polyphenol of 13.24g, yield 15.27%, wherein polyphenol content is 90.79%, content of caffeine 1.47%.Product is through gas Chromatographic Determination, and organic solvent residual is zero.Get thick caffeine 4.85g in addition, wherein contain caffeine 3.15g, content of caffeine 65.0%.

Claims

1, from tealeaves, produces the method for tea-polyphenol, with the ethanolic soln backflow lixiviate of broken tea through 60-100 ℃ hot water or 20-80%, broken tea and said hot water or ethanolic soln were by weight 1: 8 proportioning, after lixiviate 20-90 minute, tealeaf residue is removed in press filtration, obtain tea juice, obtain concentrated tea juice I through vacuum concentration; Said concentrated tea juice I is put into the supercritical carbon dioxide extraction still, use supercritical carbon dioxide extraction, keep extraction kettle pressure 250-350 crust, temperature 30-70 ℃, keep separating still pressure 30-80 crust, temperature 30-60 ℃, extracted 4-10 hour, separate caffeine: take out raffinate tea juice and carry out vacuum concentration, obtain concentrated tea juice II, make tea-polyphenol through vacuum-drying.

2, by the said method of claim 1, wherein said concentrated tea juice II extracts tea-polyphenol with ethyl acetate extraction at least twice, and the combined ethyl acetate phase makes tea-polyphenol through concentrating under reduced pressure and vacuum-drying.

3, by claim 1 or 2 said methods, be that wherein said tea-polyphenol is put into the supercritical carbon dioxide extraction still, use supercritical carbon dioxide extraction, keep extracting pressure 200-300 crust, temperature 30-70 ℃, keep separating still pressure 30-80 crust, temperature 30-60 ℃, extracted 2-5 hour, slough residual solvent.