Studies On Quality And Benefit Of The Wuyi Rock Tea Produced By Different Refining Roasting Styles

Wuyi Rock tea is one of special tea in Fujian,which belongs to semi-fermented Oolong tea.The roasting process is essential for the quality formation of Wuyi Rock tea which has typical roast and floral or fruity aroma.This subject studied on the differences of biochemical indicators,aroma and sensory quality of Wuyi Rock tea roasted by three kinds of roasting styles,including traditional charcoal roasting,chain plate dryer,electric dry oven.Different environmental parameters in different refining roasting workshop were dectected and the effects caused by it on the personnel related to tea-processing and ecological environment were analysed.Also,we applied related economic theory of cost-benefit to the comparative analysis of the cost-effectiveness of different roasting methods.By integrating the analysis of tea quality,environment benefit with economic benefit,this paper enriched and modified the basic theory futher in both aspects of tea processing and tea economy;holded the promise of providing technical guidance for carrying out the continuous and energy-efficient production of Wuyi Rock tea.The main results are as follows:1 Quality comparison of Wuyi Rock tea with different refining roasting stylesWuyi Rougui and Rougui semi-made tea selected as material were dried by using the chain plate dryer,electric oven and charcoal roasting styles.The results showed that:Wuyi Rougui and Rougui dried by chain plate dryer had the highest content of amino acid,tea polyphenol and caffeine among three roasting technologies and had the highest content of water extract,TR,TF when dried by electric oven and had highest content of TB when dried by charcoal roasting.Except caffeine,the difference of content of biochemical components among three kinds of roasting technologies were significant(P<0.05).Rougui and Rougui roasted by 3 ways of roasting process had similar aroma components which consisted of relatively high content of alcohols,olefins and lipid compounds.Composite score of aroma quality represented by F value in Wuyi Rougui and Wuyi Rougui were analyzed by the method of principal component analysis,the ranking of Wuyi Rougui's F value was ZS-A>ZS-C>ZS-B>BS-A>BS-C>BS-C,the ranking of Wuyi Rougui's F value was BR-A>ZR-A>BR-C>ZR-C>BR-B>ZR-B.The results of sensory evaluation showed that Wuyi Rock Shuixian,Wuyi semi-Rock Shuixian and Wuyi Rock Rougui made by charcoal roasting scored highest,followed by chain plate dryer and electric oven roasting;the score of Wuyi semi-Rock Rougui made by chain plate dryer was the highest,which was followed by charcoal roasting and electric oven roasted.Wuyi Rock tea made by chain plate dryer had brown or black brown color appeared on dry tea leaves,bright clear liquor,delicate fragrance,mellow taste;However,the tea made by electric oven roasting had pitch-black color of dry tea,orange soup with sweet,strong or mellow taste;charcoal roasting were black bloom color of dry tea,bright orange liquor,pure aroma,pure and mild taste.Based on the analysis of biochemical,aroma and sensory quality,chain plate dryer roasting is beneficial to form good quality for semi-rock Rougui and semi-rock Rougui,and charcoal roasting is beneficial to rock Rougui and Rougui.2 Comparison of environmental parameters of different refining roasting workshopUsing the environment thermo-hygrometer,instrument of measuring total dust,instrument,of measuring PM10,PM2.5 and instrument of measuring CO2 to detect environment parameters of chain plate dryer workshop,electric oven roasting workshop and charcoal roasting workshop.The results show that:The average temperature(37.27 ?)in sunny and rainy days of charcoal roasting workshop was significantly higher than chain plate dryer roasting workshop(28.36?)and electric oven roasting workshop(28.11?),the average relative humidity of them show that:electric oven roasting workshop(75.06%)>chain plate dryer roasting workshop(73.67%)>charcoal roasting workshop(43.95%);The differences of temperature and humidity of chain plate dryer roasting workshop between sunny and rainy days were significantly(P<0.05),that differences of charcoal roasting workshop didn't reach the significant level.The average content of total dust in chain plate dryer roasting workshop was the highest(24.36 mg/m3),the carbon roasting workshop was the second(19.90mg/m3),the electric oven roasting workshop was the lowest(11.37 mg/m3);The content of PM10 and PM2.5 show that:chain plate dryer roasting workshop>charcoal roasting workshop>electric oven roasting workshop;The content of total dust,PM10 and PM2.5 of these roasting workshop on sunny days were significantly higher than those of rainy days(P<0.05).The average concentration of CO2 in carbon roasting workshop,chain plate dryer roasting workshop and electric roasting workshop were 5049.88ppm,775.36ppm and 528.39ppm respectively.The CO2 concentration of charcoal roasting workshop were chain plate dryer roasting workshop,electric oven roasting workshop 9.56 times,6.51 times and 6.51 times from the atmosphere.3 Efficiency comparison of different refining roasting stylesBased on the field investigation of Wuyi Rock tea refining roasting manufacturers,combining with refining roasting test results,measure out three kinds of costs and benefits of different ways of roasting,the result showed that:The cost using charcoal roasting way to produce 1kg of tea(8.856 yuan)is significantly higher than the chain plate dryer roasting(1.928 yuan)and an electric oven roasting(1.819 yuan)costs.The labor cost of producing 1kg tea using charcoal roasting higher than the chain plate dryer roasting(0.667 yuan)and electric oven roasting(0.781 yuan),is the major reason for charcoal roasting high cost.Three kinds of roasting modes equipment depreciation rates were lower,charcoal roasting costs(2.133 yuan/kg)higher than the chain plate dryer(1.093 yuan/kg)and electric oven roasting(0.983 yuan/kg)in energy costs.Without considering the case of roasting efficiency,Rougui and Rougui using charcoal roasting profit margin(21%,13%)the highest,semi-Rock and semi-Rock Rougui and Rougui using chain plate dryer roasting profit margin(14%,25%)the highest.Represented by semi-rock Rougui and Rougui use chain plate dryer roasting is helpful to promote the comprehensive benefits of the tea.Wuyi Rock tea charcoal baked process is China's intangible cultural heritage,excellent should inherit and develop skills,but need to consider economic,social and environmental benefits to control charcoal baked tea production.