Background technology
China is Tea Production big country, and tealeaves (dry product) annual production has reached 1,400,000 tons, and its low and middle-grade tea, fannings account for more than 20%.The utilization of not gathering of more substantial summer autumn tea leaf is still arranged every year.At present, extract tealeaves deep processings such as preparation instant tea powder, tea-polyphenol, catechin, theanine, tea polysaccharide and formed big technical scale from low-grade tea, fannings, summer autumn tea, still, the suitability for industrialized production of natural tea essence still is blank.Though for the existing many reports of the research of tea essence, essential oil, spices, also there are some to declare patent at present, owing to well do not consider the industrialization cost, and have different technical disadvantages, and can not realize actual use.For example, supercritical extraction tea essence method can't actually be used owing to reasons such as device is expensive, treatment capacity is little, power consumption is big make cost very high; Essence and flavoring agent in the open steam distillation extraction tealeaves (claiming essential oil again) method, tooling cost is higher, owing to do not consider the cold-trap collection technique, makes the lower boiling composition of essence volatilization loss in preparation process in the tealeaves simultaneously, causes the product yield low, second-rate.
Some declare disclosed patented technology, as application number is 93102247.9 (to the methods of tealeaves comprehensive process and utilization), be that the gas phase cooling that produces when evaporating recycle-water, solvent in preparation tealeaves caffeine and the instant tea process is reclaimed and obtained tea essence, such product is the part of tea aroma composition, and yield is low, of poor quality; Application number is 200810204732.7 (are feedstock production black tea essence and the purposes in cigarette thereof with black tea), its technical scheme is earlier in oven dry more than 120 ℃ with black tea, again through ethanol or ethyl acetate extraction, tea grounds after the extraction obtains enzymolysis solution through tannase or pectinase enzymatic hydrolysis again, the material that at last the above-mentioned extracting solution that obtains and enzymolysis solution are mixed, concentrate, drying obtains, strictly speaking the product that obtains of this technical scheme is not tea essence but tea leaf extract; Application number is 200810043528.1 (black tea essences), is tealeaves to be extracted other plant milk extract and other essence such as mixing such as jononeionone, wintergreen oil such as medicinal extract, the bark of eucommia, and the spray-dried product that makes belongs to the mixed type non-natural prods.
Owing to above reason, the tea essence of China's use at present is import mostly, and its main component is that part natural tea essence adds the mixture that some compound essences are formed.
Summary of the invention
The purpose of this invention is to provide a kind of natural tea essence, its preparation method is provided simultaneously,, satisfy domestic demand this product to improve China's natural tea essence throughput with preparation of tea.
Natural tea essence with preparation of tea of the present invention is to be raw material with tealeaves, is undertaken by adding polygalacturonase, cellulase or polygalacturonase+cellulase prozyme that complex enzyme hydrolysis, release, reduced steam distillation, cold-trap reclaim, cryogenic freezing concentrates and carry out oily water separation and get with the method preparation of anhydrous sodium sulphate absorption micro-moisture.
Natural tea essence preparation method with preparation of tea of the present invention is:
(1) enzymolysis of tealeaves cell walls
Tea raw material is ground into 30~100 orders earlier, add pure water, the pure water consumption is 10~20 times of dry weight of tea leaves, regulating the pH value is 3~8, adds polygalacturonase, cellulase or polygalacturonase+cellulase prozyme and carries out enzymolysis, and described polygalacturonase, cellulase or the total consumption of its prozyme are 0.1~2.0% of tealeaves gross weight, temperature is 30~60 ℃, action time, 3~10h stirred in the enzymolysis process, and speed is 10~100rpm;
(2) enzymolysis of tealeaves flavor precursors discharges
After step (1) is finished, add beta-glucosidase in above-mentioned system, the consumption of this enzyme is 0.1~2.0% of a tealeaves gross weight, and regulating pH is 4~9, and temperature is 40~70 ℃, action time 2~8h, stir speed (S.S.) is 10~100rpm;
(3) reduced steam distillation, cold-trap reclaim essence
After step (2) is finished, do not need the enzyme that goes out, then adopt the reduced steam distillation method to extract aroma component, and cooling is reclaimed;
(4) essence concentrating and separating, purifying
Adopt cryogenic freezing to concentrate, divide with whizzer more dried up-oil, collect upper strata essential oil part, remove wherein micro-moisture through anhydrous sodium sulphate absorption again, obtain highly purified natural tea essence.
Described raw material is the bright leaf of tea or green tea, black tea, oolong tea cured leaf.
Described enzymolysis connects the condenser backflow in the closed stainless steel container carries out.The perfume ingredient that comes out along with wet distillation can utilize the condenser cooling to reclaim, and heat-eliminating medium is a salt solution, and cooling is reclaimed under-5~+ 4 ℃ of temperature condition.
Adopt the cryogenic freezing whizzer during subzero fractionation, temperature is-5~+ 4 ℃.
Preparation method of the present invention adopts polygalacturonase+cellulase combined-enzyme method, helps destroying the cell walls of tealeaves, separates out thereby help the free of aroma component, is distilled out easily, improves the essence yield; The precursor substance of essence in the tealeaves, itself be micromolecular aroma component combine with the different sugar molecule form than macromolecular cpd, itself does not have fragrance, beta-glucosidase can act on these materials, make it enzymolysis, thereby discharge flavour substances, obtain more aroma component.Adopt the reduced steam distillation to carry out at a lower temperature, help keeping the original local flavor of tealeaves, can shorten the production time simultaneously, raise the efficiency, treatment capacity is big, cost is low; Adopt that salt solution is low as the heat-eliminating medium cost, toxicological harmless, be suitable for large-scale application; The anhydrous sodium sulphate toxicological harmless, repeatedly use after can drying.In a word, that the present invention is expected to become is energy-conservation, low-cost, green, the method for the high-purity natural tea essence of the fragrant feature of the different tea of suitability for industrialized production efficiently, provides a kind of good new channel for the efficient utilization of a large amount of tealeaves of China.Therefore the present invention directly prepares high-purity natural tea essence method from tea raw material, will be significant to the deep processing and the increasing both production and income of human health and tealeaves.
Embodiment
Below in conjunction with specific embodiment, the invention will be further described.
Embodiment 1-green tea essence
Its preparation method carries out according to the following steps:
(1) enzymolysis of tealeaves cell walls
Weigh the bright leaf 1000g (the about 250g of dry weight) of tea in September, be ground into 60 orders with choppingmachine, add pure water 2500g, regulate pH 5.5 with dilute hydrochloric acid, add commodity polygalacturonase 2.5g (dry weight of tea leaves amount 1.0%)+cellulase 2.5g (dry weight of tea leaves amount 1.0%), under 55 ℃, stir enzymolysis 5h, stir speed (S.S.) is 60rpm.
Enzymolysis connects the condenser backflow in the closed stainless steel container carries out, and the heat-eliminating medium of condenser is a salt solution, at-2 ℃ of following cooling for reflux, does not overflow to guarantee aroma component.
(2) enzymolysis of tealeaves flavor precursors discharges
After step (1) is finished, add beta-glucosidase 2.5g (dry weight of tea leaves amount 1.0%) in above-mentioned system, enzymolysis pH is 5.5, and temperature is 55 ℃, action time 3h, stir speed (S.S.) is 60rpm.Enzymolysis connects the condenser backflow in the closed stainless steel container carries out.The heat-eliminating medium of condenser is a salt solution, at-2 ℃ of following cooling for reflux, does not overflow to guarantee aroma component.
(3) reduced steam distillation, cold-trap reclaim essence
After step (2) is finished, do not need the enzyme that goes out, then feed water vapor from boiler (fire coal, electrically heated, combustion gas all can), control suitable pressure and flow, (vacuum tightness-0.8MPa) steam distillation extracts aroma component 3h, and the perfume ingredient that comes out along with wet distillation utilizes the condenser cooling to reclaim, and the heat-eliminating medium of condenser is a salt solution to adopt decompression down at 55 ℃,-2 ℃ of cooling recovery down, do not overflow to guarantee aroma component.
(4) concentrated, the purifying of essence
The essence that step (3) obtains is collected liquid, contains a large amount of moisture, and concentration is lower, adopt the cryogenic freezing whizzer in 0 ℃ of centrifugation water-oil, collect upper strata essential oil part, remove wherein micro-moisture through the absorption of anhydrous sodium sulphate packed column again, obtain highly purified natural tea essence.
The result obtains the light yellow theol of 4.63g (with dry weight basis about 1.85%).Yield is apparently higher than about 1% data of other method report.Has the peculiar fragrance of green tea.
Embodiment 2-oolong tea essence
Its preparation method carries out according to the following steps:
(1) enzymolysis of tealeaves cell walls
Weigh oolong tea (Iron Guanyin) 200g that originates from Fujian, be ground into 30 orders earlier, add pure water 3000g with choppingmachine.Regulate pH4.5 with dilute hydrochloric acid, add commodity polygalacturonase 1.5g (dry weight of tea leaves amount 0.75%)+cellulase 2.5g (dry weight of tea leaves amount 1.25%), under 50 ℃, stir enzymolysis 6h, stir speed (S.S.) is 30rpm.
Enzymolysis connects the condenser backflow in the closed stainless steel container carries out.The heat-eliminating medium of condenser is a salt solution, at 0 ℃ of following cooling for reflux, does not overflow to guarantee aroma component.
(2) enzymolysis of tealeaves flavor precursors discharges
After step (1) is finished, add beta-glucosidase 3.0g (dry weight of tea leaves amount 1.5%) in above-mentioned system, enzymolysis pH is 4.5, and temperature is 50 ℃, action time 4h, stir speed (S.S.) is 30rpm.Enzymolysis connects the condenser backflow in the closed stainless steel container carries out.The heat-eliminating medium of condenser is a salt solution, at 0 ℃ of following cooling for reflux, does not overflow to guarantee aroma component.
(3) reduced steam distillation, cold-trap reclaim essence
After step (2) is finished, do not need the enzyme that goes out, then feed water vapor from boiler (fire coal, electrically heated, combustion gas all can), control suitable pressure and flow, (vacuum tightness-0.75MPa) steam distillation extracts aroma component 5h, and the perfume ingredient that comes out along with wet distillation utilizes the condenser cooling to reclaim, and the heat-eliminating medium of condenser is a salt solution to adopt decompression down at 60 ℃, 0 ℃ of cooling recovery down, do not overflow to guarantee aroma component.
(4) concentrated, the purifying of essence
The essence that step (3) obtains is collected liquid, contains a large amount of moisture, and concentration is lower.Adopt the cryogenic freezing whizzer in 0 ℃ of centrifugation water-oil, collect upper strata essential oil part, remove wherein micro-moisture through the absorption of anhydrous sodium sulphate packed column again, obtain highly purified natural tea essence.
The result obtains the light yellow theol of 4.28g (with dry weight basis about 2.14%).
Has the peculiar fragrance of oolong tea.Because oolong tea is a semi-fermented tea, has increased fragrance in the fermenting process, so yield is higher than green tea.
Embodiment 3-black tea essence
Its preparation method carries out according to the following steps:
(1) enzymolysis of tealeaves cell walls
Weigh the Keemun black tea 200g that originates from Anhui, be ground into 80 orders earlier with choppingmachine, add pure water 4000g, regulate pH 5.0 with dilute hydrochloric acid, add commodity polygalacturonase 2.5g (dry weight of tea leaves amount 1.25%)+cellulase 1.5g (dry weight of tea leaves amount 0.75%), under 45 ℃, stir enzymolysis 8h, stir speed (S.S.) is 50rpm.
Enzymolysis connects the condenser backflow in the closed stainless steel container carries out.The heat-eliminating medium of condenser is a salt solution, at 2 ℃ of following cooling for reflux, does not overflow to guarantee aroma component.
(2) enzymolysis of tealeaves flavor precursors discharges
After step (1) is finished, add beta-glucosidase 4.0g (dry weight of tea leaves amount 2.0%) in above-mentioned system, enzymolysis pH is 5.0, and temperature is 45 ℃, action time 4h, stir speed (S.S.) is 50rpm.Enzymolysis connects the condenser backflow in the closed stainless steel container carries out.The heat-eliminating medium of condenser is a salt solution, at 2 ℃ of following cooling for reflux, does not overflow to guarantee aroma component.
(3) reduced steam distillation, cold-trap reclaim essence
After step (2) is finished, do not need the enzyme that goes out, then feed water vapor from boiler (fire coal, electrically heated, combustion gas all can), control suitable pressure and flow, (vacuum tightness-0.70MPa) steam distillation extracts aroma component 4h, and the perfume ingredient that comes out along with wet distillation utilizes the condenser cooling to reclaim, and the heat-eliminating medium of condenser is a salt solution to adopt decompression down at 65 ℃, 0 ℃ of cooling recovery down, do not overflow to guarantee aroma component.
(4) concentrated, the purifying of essence
The essence that step (3) obtains is collected liquid, contains a large amount of moisture, and concentration is lower.Adopt the cryogenic freezing whizzer in 0 ℃ of centrifugation water-oil, collect upper strata essential oil part, remove wherein micro-moisture through the absorption of anhydrous sodium sulphate packed column again, obtain highly purified natural tea essence.
The result obtains 4.55g light brown black tea essence oil (with dry weight basis about 2.28%).Has the peculiar fragrance of black tea.Because black tea is full fermented tea, has increased fragrance in the fermenting process, so yield is higher than green tea and oolong tea.