GREENTEAEXTRACTHAVINGANIMPROVEDTASTEAND

MANUFACTURINGMETHODTHEREOF Technical Field [1] The present invention relates to green tea extract from which components with a bitter taste or an astringent taste are removed without a loss of biological active compounds of catechins group and a method for manufacturing thereof. Background Art [2] Recently, the green tea has been an interesting substance as healthy food and comprises many of useful component; because catechin compounds among them have an antioxidant effect, much study therefor is in progress. Among polyphenols species in the green tea, the catechin compounds consist of epigallocatechin (EGC), epicatechin (EC), epigallocatechin gallate (EGCG), epicatechin gallate (ECG) etc. It was reported that the catechin compounds showed biological activities such as removing oxygen free radicals by an antioxidant effect; preventing hypertention, obesity, heart disease and cholesterosis; anti-inflammatory effect and antithrombosis effect etc.(see Masami Suganuma, et al., Mutation Research, 428,339(1999); Chi Han, et al., Cancer letter, 114,153(1997); W. S. Kang, et al., Nutritional Pharmaceuticals, 16, 315(1999); and Ian R. Record, et al., Mutation Research, 422,191(1998)). [3] It was reported that prior art related to the biological active compounds in the green tea is a method of manufacturing extract comprising plenty of catechins (see Korea Patent Publication No. 2000-46079 and Korea Patent Publication No. 2001-35410) or a method of purifying the catechins by chromatography using macropore resin (see U.S. Patent No. 2003/83270). Methods of increasing catechins content have been studied as methods of manufacturing beverages or green tea extract fortified with the biological active compounds like methods above. [4] However, there have been no inventions up to date that increase drmkability of green tea by removing the bitter or astringent taste while having the biological activities by maintaining the catechins content of the green tea. In order to maximize the biological activities of the green tea, the green tea extract should be prepared to comprise highly concentrated catechin(generally scores of mg/ml), but customers feel some reluctance about the bitter taste or the astringent taste provided that the green tea extracts in high concentration in order to intake large amount of the catechins. Therefore green tea products selling at markets in present have been manufactured in low content of the catechin by conducting either that a little of the green tea is extracted in a large amount of water or that a amount of the green tea is extracted for short time. Further in the process extracting the catechins from the green tea, the catechins are catalyzed by metal ions and easily oxidized into theaflavin and thearubigin, the polyphenols with high molecular weight. The oxidized polyphenols generate the compounds with higher molecular weight in combination with caffeines, proteins, pectins and metal ions extracted from the green tea extract. The bitter taste inhibiting the drinkability is attributed to the oxidized polyphenols and the combined complexes. Disclosure of Invention Technical Problem [5] The present invention relates to green tea extract from which a bitter taste or an astringent taste are removed without a loss of biological active compounds of catechins group and a method for manufacturing thereof which resolving said problems. Technical Solution [6] More particularly, the present invention provides the green tea extract from which several complexes and oxidized polyphenols originated from extracted the green tea is removed, thus including catechins with only non-oxidized form. The present invention also provides the method for filtration according to molecular weight in order to obtain the green tea extract like above. [7] The present invention also provides a proper pore-size (the standard of filtrated molecular weights) of membrane used in the method for filtration. [8] The present invention also provides the various compositions comprising green tea extract from which a bitter taste or an astringent taste are removed without a loss of biological active compounds of catechins group. [9] The present invention is explained in detail. [10] First of all, the present inventors thought that the components of the green tea could be separated by a size (molecular weight). Particularly the inventors found out a surprising fact that the components could be separated by using following fact which biological active compounds among the components in the green tea have mostly small sizes (molecular weights), while biological inactive polysaccharide with the bitter taste or the astringent taste, the brownish-oxidized polyphenols, and oxidatively polymerized intermediates and other complexes are more larger sizes (molecular weights). [11] There are size exclusion gel filtration, membrane filtration etc. as a separation process according to the molecular weight but the membrane filtration of a proper method for mass production is more preferred. [12] When the filtration was conducted using the filtration membrane with particular pore-size, the catechins of biological active compounds mostly passed through the membrane, while biological inactive and badly tasty components were effectively removed by the filtration. [ 13] The inventors found out proper criterion in order to separate the catechins of the biological active compounds from the biological inactive and badly tasty components. Membranes with cut-off value of several molecular weights were used for a test. In result, the membranes having cut-off value of about 500 to 5,000 dalton was preferred. Particularly, the membranes having cut-off of about 1,000 to 3,000 dalton was the most desirable. [14] The cut-off of the about 500 to 5,000 dalton is properly adopted by membrane materials and types, applied pressure and flow rates of subjects to be filtrated, which is apparent to those skilled in the art. [15] The reluctance to drinking was the most significantly decreased as the various favorable effects of the green tea were maintained by the filtration of the present invention. Moreover when products of the present invention with increased transparency were manufactured, the customer compliance was improved. The catechins of the biological active compounds also can be added to beverages without many influences on the taste when the variety of beverages are manufactured by using the mildly tasty green tea extract as the biological activities are remaining. [16] The membranes are generally divided into microfiltration membrane, ultrafiltration membrane, nanofiltration membrane and reverse osmosis membrane depending on membrane pore and molecular weight cut-off (MWCO). Any membrane for the filtration of the present invention among the membranes is not matter provided that the membrane can remove the biological inactive compounds having the bad taste and molecular weights of beyond particular size. [17] The membrane is also divided into plate-and-frame, spiral, tube and hallow fiber depending on what the type is processed into and any membrane is not matter to use provided that the membrane is served for the purpose of the prevent invention. [18] It is not matter ether dead-end type or crossflow type depending on filtration types. Pressure can be applied or not depending on cases. [19] Moreover there are collodion, gelatin, cellophane, Polyamides, polyetherimide etc. as materials of the membrane, which of them can but not limited to be used. [20] The method of the present invention as described above can be used for various extracts using the green tea; for example oil phase extract such as fatty acid and alcohol as well as aqueous phase extract. Advantageous Effects [21] The present invention provides the green tea extract from which components with the bitter or astringent taste are removed without a loss of biological active compounds of catechins group and a method of manufacturing thereof. That is, the present invention can provide the green tea extract with decreased the reluctance about because the bitter or astringent taste is removed and the transparency is increased and the method for manufacturing thereof. Brief Description of the Drawings [22] The following figures incorporated herein and constituting a part hereof illustrate the presently preferred embodiments of the present invention and will explain a theory of the present invention along with detailed explanation of the following preferred em¬ bodiments. [23] FIGURE 1 is a graph showing the result of a sensory test showing the content change of total catechins in green tea extract filtrated through membranes with different pore-size and a removal rate of the bitter or astringent taste. MWL (molecular weight limit) 500 shows the result of the test using the green tea extract filtrated through the membrane having the cut-off of molecular weight 500 dalton. MWLlOOO shows the result of the test using the green tea extract filtrated through the membrane having the cut-off of molecular weight 1000 dalton. MWL3000 shows the result of the test using the green tea extract filtrated through the membrane having the cut-off of molecular weight 3000dalton. [24] FIGURE 2 is a graph showing content change of each catechins components in filtrating the green tea extract. [25] FIGURE 3 is a graph showing content change of epigallocatechin gallate, epicatechin, epicatechin gallate and epigallocatechin in filtrating the green tea extract. [26] FIGURE 4 is a graph showing that oxidized polyphenols and complexes formed by combination of oxidized polyphenols and other components are decreased in filtrating the green tea extract. [27] FIGURE 5 is a graph showing that the oxidized polyphenols compounds are decreased in filtrating the green tea extract. Best Mode for Carrying Out the Invention [28] The present invention is explained concretely by following embodiments. The following examples are given for the purpose of illustrating various embodiments of the invention and the invention is not to be limited by the embodiments. [29] Example 1 [30] The green tea cultivated in Korea was used for a sample. The green tea was extracted in 800C water and was filtrated through the membrane at 50psi. The filtration membranes (Millipore ) having the cut-off of the molecular weight 500, 1000 and 3000 dalton were employed on the basis of the molecular weight of the catechins in the green tea and polymer such as cellulose, cellulose acetate, polysulfone and polyvinyli- denefluoride were used as the material of the filtration membrane. [31] Quantitative analysis of the catechins was conducted by using the property which the catechins form the chelate compound in combination with Fe2+ ion and the chelate compound absorbs light at 550nm(see Hideo Iwahashi, Biochem. J., (2000) 346,265). The catechins were optionally detectable because only non-oxidized catechins reacted with Fe2+ ion and the oxidized and polymerized polyphenols wasn't allowed to interfere in the analysis. After Fe2+ ion reacted with the green tea extract, an increasing rate of absorbance thereof at 550nm was kinetically analyzed to measure the content of the catechins. The analysis on the catechin content was also confirmed by analyzing the absorbance at 280nm(absorption wavelength of the catechins) for an accurate analysis. [32] Experiment 1 [33] In the example 1, the reduction of the bitter or astringent taste was evaluated by using green tea extract filtrated and prepared. The sensory test was conducted as the measurement. The change of the taste was measured by allowing ten adults between the ages of 20 and 40 to sample the green tea extract on double blind test. The taste of the green tea extract passing the filtration was evaluated by point, wherein the bitter and astringent taste of non-filtrated green tea extract set 10 points. [34] Fig. 1 shows the results of both example 1 and experiment 1, wherein the result is about that the green tea extract is filtrated over three times through the membrane with filtration ablility each the molecular weight 500, 1000 and 3000 dalton. The content of the filtrated catechins was expressed as a percentage, wherein the content of the non- filtrated catechins set 100% prior to filtration. When the filtration was conducted through the membrane of 500, 1000 and 3000 dalton, each of them showed the filtration efficiency of 5%, 60% and 95%. The green tea extract filtrated through the membrane of 1000 and 3000 dalton was improved in the taste. [35] Example 2 [36] HPLC was conducted and analyzed in order to observe each content change of the biological active epigallocatechin gallate and epicatechin among components of the catechins. Waters HPLC and Waters Multiwavelength meter were used as an analysis device and C18 or ODS HPLC column (manufactured by Waters) for analysis was used as HPLC column. Distilled water including 0.1% trifluoroacetatic acid (TFA) and acetonitrile were conducted for 30 minutes by linear partition and the absorbance thereof at 280 nm was analyzed. The epigallocatechin, epicatechin, epicatechin gallate and epigallocatechin comprised in the green tea extract were analyzed according to time when epigallocatechin gallate (EGCG, manufactured by Sigma) with purity of over 95%, epicatechin (EC, manufactured by Sigma) with purity of over 98%, epicatechin gallate (ECG, manufactured by Sigma) and epigallocatechin (EGC, man¬ ufactured by Sigma) were extracted, and the molecular weight of the extract was as- certained by FAB-Mass for verification. The catechins were detected at about between 5 and 10 minutes in the linear gradient of distilled water and acetonitrile for 30 minutes. According to the result of integrating HPLC peak, epigallocatechin gallate, epicatechin, epicatechin gallate and epigallocatechin were filtrated, as the catechins species in Figure 1 were generally decreased. [37] Fig. 2 shows the change of HPLC peaks when the green tea extract was filtrated through the filtration membrane for molecular weight 1000 dalton and Fig. 3 shows results of analyzing transmission rate of epigallocatechin gallate, epicatechin, epicatechin gallate and epigallocatechin by integrating HPLC peaks, which meant the filtration efficiency of over 60%. Therefore, it was shown the fact that the filtration efficiency of the catechins was identical with that of each component of the catechins. [38] Example 3 [39] The absorbance of the green tea extract before and after filtration was measured at 190-1 lOOnm wavelengths by using UV spectrometer (manufactured by Shimadzu) in order to observe the filtration patterns of the components except biological active catechins when the green tea extract was filtrated. Fig. 4 shows the result of filtration through the filtration membrane with the molecular weight 1000 and 3000 dalton. [40] The absorbance patterns of the green tea extract before and after filtrated at between 190 and 300nm were similar to one another and the much decrease in the component absorbing light at between 310 and 600nm was measured, which is identical with the range of the wavelength that the oxidized polyphenols or polymers thereof absorb light. Therefore the result above means that undesirable components of the green tea extract is removed. [41] Example 4 [42] HPLC analysis was conducted by using the same device with the example 2 in order to analyze the removal profile of oxidized or polymerized polyphenols having the bitter or astringent taste and weak biological activity when the green tea extract was filtrated. The extraction profile was analyzed at 350nm wavelength which the oxidized or polymerized polyphenols absorb light. When the green tea extract was filtrated through the filtration membrane with the molecular weight 1000 dalton, the oxidized or polymerized polyphenols were detected at about between 10 and 20 minutes in the linear gradient of distilled water and acetonitrile for 30 minutes. It showed that over 60% of the each components was decreased when the filtration efficiency was calculated by integrating peaks detected. Industrial Applicability [43] The present invention provides the green tea extract from which the bitter or astringent taste are removed without a loss of biological active compounds of catechins group and the method of manufacturing thereof. That is, the present invention relates to the green tea extract with decreased the reluctance to drinking because the bitter or astringent taste is removed and the transparency is increased and the method for manu¬ facturing thereof. [44] It should be understood that various changes and modification to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages.