Research On Tea Quality Information Collection And Control Of Production Line For Green Tea Or Black Tea

The mode of tea process has been changed from crafts or single machine operation to automated,continuous and intelligent production lines,which greatly increase the production efficiency and by only one of which many tea varieties could be processed.Tea quality directly correlate with process parameters of production lines,so it is one of the most important tasks to find the best process route in mechanized tea production.Using Maoxie and Fuyun No.6(camellia sinensis)as raw materials,a production line both for black tea and green tea was observe by orthogonal test on parameters of reserving,withering,fixing,the first rolling,the second rolling,fermenting,the first drying,re-drying,etc.and optimal parameters were obtained based on online tea quality information gathering combined with online sensory appraisal.The optimal parameters for black tea by Maoxie(camellia sinensis)were:(1)reserving fresh leaves with 6cm thickness for lh,(2)withering leaves with 6cm thickness for 24.5h,(3)the first rolling with 45kg weight at 45r/min and the second rolling with 35kg weight at 45r/min,using the distance between the top and the lip of a roller as a pressure indicator,which was "20cm for 5min?50cm for 15min?65cm for 20min?40cm for 5min?20cm for 1min" for the first rolling and "25cm for 15min?40cm for 10min?55cm for 25min?30cm for 5min?60cm for 5 min" for the second rolling,(4)fermenting with 8cm thickness for 4h?6h at humidity beyond 95%and temperature below 28?,(5)the first drying at 150°C for 10min,(6)re-drying at 110? for 20min.The optimal parameters for green tea by No.6(camellia sinensis)were:(1)reserving fresh leaves with 6cm thickness for lh,(2)withering leaves with 6cm thickness for lh,(3)fixing with 1.5kg weight at 16r/min using the temperature of the front,the middle and the back of fixing machines at 320oC,240?,200?,respectively,(4)the first rolling with 40kg weight and the second rolling with 35kg weight at 45r/min,using the distance between the top and the lip of a roller as a pressure indicator,which was "15cm for 10min?25cm for 10min?60cm for 20min?35cm for 5min?40cm for 5min" for the first rolling and "20cm for 10min?45cm for 15min?60cm for 25min?35cm for 5min?20cm for 2 min" for the second rolling,(5)the first drying at 120? for 10min,(6)re-drying at 80? for 20min.Biochemical components of samples from each procedure of the tea production line were analyzed.Using water extracts(Y)as a dependent variable,amino acids(X1),polyphenols(X2),caffeine(X3),flavone(X4),black tea of theaflavins(X5),Thearubigins(X6)and Theabrownins(X7),green tea of ehlorophyll-a(X5),chlorophyll-b(X6),total chlorophyll(X7),carotenoids(X8)3 pH(X9),conductivity(X10)as independent variables,multiple linear regression analyses were conducted to quantify biochemical compounds contents and qualities of made tea and provide theoretical bases for quality control of process procedures.There were five regression equations obtained for black tea procedures:Y=65.866-4.533X3-1.548X5 for withering,Y=22.142-1.118X2 for the first rolling,Y=-3.589+0.895X7+0.609X2+4.479X3 for the fermenting,Y=-23.227-2.101X4 for the first drying and Y=45.403+6.784X1-6.589X3 for re-drying;while there were four regression equations obtained for green tea procedures:Y=64.223+4.486X1 for withering,Y=45.031-8.182X1+4.521X3 for the first rolling,Y=58.768-16.854X6 for the first drying and Y=64.140-19.412X6 for re-drying.There were slight differences between online leaves samples and counter samples on sensory evaluation results dried and there were significant correlations between tea color measurement results with pigments,indicating that online sensory appraisals and online color detections had a certain conductive meaning for the quality control of production lines.Each procedure of the production line could be discriminated distinctly by the electronic nose technology combined with principal component analysis.The production line both for black tea and green tea made processes clean,continuous and automated and had great practical value.By collection of online tea quality information(sensory evaluation,color detection,electronic nose and electronic tongue technology)would provide theoretical bases for tea quality control,database establishment to guide tea production and improve product quality.