To explore the volatile profiles and the contents of ten bioactive components(polyphenols and caffeine) of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain,17 samples of three tea varieties were ...To explore the volatile profiles and the contents of ten bioactive components(polyphenols and caffeine) of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain,17 samples of three tea varieties were analyzed by headspace-solid phase microextraction-gas chromatography-mass spectrometry(HS-SPME-GC-MS) and high-performance liquid chromatography(HPLC).A total of 75 volatile components were tentatively identified.Laomaner(LME),Laobanzhang(LBZ),and other teas on Bulang Mountain(BL) contained 70,53,and 71 volatile compounds,respectively.Among the volatile compounds,alcohols(30.2%-45.8%),hydrocarbons(13.7%-17.5%),and ketones(12.4%-23.4%) were qualitatively the most dominant volatile compounds in the different tea varieties.The average content of polyphenol was highest in LME(102.1 mg/g),followed by BL(98.7 mg/g) and LBZ(88.0 mg/g),while caffeine showed the opposite trend,27.3 mg/g in LME,33.5 mg/g in BL,and 38.1 mg/g in LBZ.Principal component analysis applied to both the volatile compounds and ten bioactive components showed a poor separation of samples according to varieties,while partial least squares-discriminant analysis(PLS-DA) showed satisfactory discrimination.Thirty-four volatile components and five bioactive compounds were selected as major discriminators(variable importance in projection(VIP)>1) among the tea varieties.These results suggest that chromatographic data combined with multivariate analysis could provide a useful technique to characterize and distinguish the sun-dried Pu-erh tea leaves from ancient tea varieties on Bulang Mountain.展开更多
For many, manypeople in theworld,a roadexclusively devot-ed to the tea-horse tradewould be considered some-thing of a tall tale.However,such a road did exist,fromthe Tang Dynasty(618-907)to the opening of the Yun-nan-...For many, manypeople in theworld,a roadexclusively devot-ed to the tea-horse tradewould be considered some-thing of a tall tale.However,such a road did exist,fromthe Tang Dynasty(618-907)to the opening of the Yun-nan-Tibet and Sichuan-TibetHighways in the 196Os.Insome areas,sections of theroad are still used for trans-port purposes.展开更多
The Chinese tea drinking habit started during the Qin and Han dynasties,and had its origin in Bashu.During the Tang and Song dynasties,Bashu tea reached a high level of production with large sales.As the birthplace of...The Chinese tea drinking habit started during the Qin and Han dynasties,and had its origin in Bashu.During the Tang and Song dynasties,Bashu tea reached a high level of production with large sales.As the birthplace of the tea culture,Bashu has made great contributions to both the Chinese and global tea culture.展开更多
To determine the age of oil-tea camellia trees, regression equations including Logistic, Mitscherlich, Gompertz, Korf, and Richards were used to calculate accumulative growth rate using basal trunk disc and investigat...To determine the age of oil-tea camellia trees, regression equations including Logistic, Mitscherlich, Gompertz, Korf, and Richards were used to calculate accumulative growth rate using basal trunk disc and investigate the relations between the age of oil-tea camellia trees and their growth rate of secondary trunk. The Gompertz equation Y=71.296 1exp （-3.874 4exp （-0.006 4t）） was the most optimal equation to simulate the accumulative growth rate of basal trunk disc. This equation could be used to estimate the age of oil-tea camellia trees that grow under similar environmental conditions. The Korf equation Y=576.900 1exp （-4.153 0x -0.314 2 ） was the best equation to describe the relation between the age and growth rate of different secondary trunks. With the adjustment coefficient and average growth of different secondary trunk discs, it is possible to predict the age of ancient oil-tea camellia trees that grow under similar environmental conditions. In addition, taking three or more discs from the same diameter group and calculating their average growth rate could lead to more accurate results. For trees that grow in different areas, environmental conditions should be carefully considered when using the above two equations to predict the age of ancient oil-tea camellia trees.展开更多
文摘To explore the volatile profiles and the contents of ten bioactive components(polyphenols and caffeine) of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain,17 samples of three tea varieties were analyzed by headspace-solid phase microextraction-gas chromatography-mass spectrometry(HS-SPME-GC-MS) and high-performance liquid chromatography(HPLC).A total of 75 volatile components were tentatively identified.Laomaner(LME),Laobanzhang(LBZ),and other teas on Bulang Mountain(BL) contained 70,53,and 71 volatile compounds,respectively.Among the volatile compounds,alcohols(30.2%-45.8%),hydrocarbons(13.7%-17.5%),and ketones(12.4%-23.4%) were qualitatively the most dominant volatile compounds in the different tea varieties.The average content of polyphenol was highest in LME(102.1 mg/g),followed by BL(98.7 mg/g) and LBZ(88.0 mg/g),while caffeine showed the opposite trend,27.3 mg/g in LME,33.5 mg/g in BL,and 38.1 mg/g in LBZ.Principal component analysis applied to both the volatile compounds and ten bioactive components showed a poor separation of samples according to varieties,while partial least squares-discriminant analysis(PLS-DA) showed satisfactory discrimination.Thirty-four volatile components and five bioactive compounds were selected as major discriminators(variable importance in projection(VIP)>1) among the tea varieties.These results suggest that chromatographic data combined with multivariate analysis could provide a useful technique to characterize and distinguish the sun-dried Pu-erh tea leaves from ancient tea varieties on Bulang Mountain.
文摘For many, manypeople in theworld,a roadexclusively devot-ed to the tea-horse tradewould be considered some-thing of a tall tale.However,such a road did exist,fromthe Tang Dynasty(618-907)to the opening of the Yun-nan-Tibet and Sichuan-TibetHighways in the 196Os.Insome areas,sections of theroad are still used for trans-port purposes.
文摘The Chinese tea drinking habit started during the Qin and Han dynasties,and had its origin in Bashu.During the Tang and Song dynasties,Bashu tea reached a high level of production with large sales.As the birthplace of the tea culture,Bashu has made great contributions to both the Chinese and global tea culture.
基金Supported by Hunan Forestry Science and Technology Project(XLK201707)
文摘To determine the age of oil-tea camellia trees, regression equations including Logistic, Mitscherlich, Gompertz, Korf, and Richards were used to calculate accumulative growth rate using basal trunk disc and investigate the relations between the age of oil-tea camellia trees and their growth rate of secondary trunk. The Gompertz equation Y=71.296 1exp （-3.874 4exp （-0.006 4t）） was the most optimal equation to simulate the accumulative growth rate of basal trunk disc. This equation could be used to estimate the age of oil-tea camellia trees that grow under similar environmental conditions. The Korf equation Y=576.900 1exp （-4.153 0x -0.314 2 ） was the best equation to describe the relation between the age and growth rate of different secondary trunks. With the adjustment coefficient and average growth of different secondary trunk discs, it is possible to predict the age of ancient oil-tea camellia trees that grow under similar environmental conditions. In addition, taking three or more discs from the same diameter group and calculating their average growth rate could lead to more accurate results. For trees that grow in different areas, environmental conditions should be carefully considered when using the above two equations to predict the age of ancient oil-tea camellia trees.
