Study On The Enzyme Activity And Quality By LED Withering Of Tieguanyin

Tieguanyin is a high arma(flower and fruit aroma)speciatyl tea.The sun-withering is the first process of the formation of Tieguanyin aroma,mellow taste and excellent quality.Spring is the Fujian Tieguanyin production peak,which often rainy and wet weather,can not be normal solar withering,leading to the tea stuffy aroma and weak taste.To compensate for the rainy weather can not be normal solar withering,the study based on the superiority of LED high efficiency and energy saving,taken Minnan Tieguanyin as the research objecthe,compare with solar withering and natural withering,to discussed the beta glucosidase activity,PPO activity,physiological and biochemical,aroma and quality of Tieguanyin on different LED monochromatic light and the combined light withering.The results of the study are as follows:1.The determination of technical parameters of LED light withering test platformDesign of LED withering lamps with different spectrum to study the real feasibility of LED light+air-source heat withering system.Results show:LED light withering test platform can control temperature and wet by air-source,the refrigerating capacity is 3240 w/h,the temperature control range of 20℃ to 50℃,control precision:plus or minus 0.5℃ and the relative humidity control range 40%-80%,accuracy of wet control:plus or minus 1.0%.Biggest wilting ability:24 kg fresh leaves/batch.Produced blue(B),yellow(Y),red(R),white(W)4 kinds of LED light,the results indicated that under the same light irradiation intensity(300μmol.m-2.s-1),irradiation distances of LED lights were different,which was about 200～280nm(B,W,R)and 130nm(Y),the yellow light distance was significantly lower than that of other LED lights,from point of view of economic and energy saving,yellow light should be used in combination with other LED lights.2.The enzyme activity changes of Tieguanyin with different LED monochromatic light witheringβ-glucosidase activity showed an upward trend in withering process.In fresh tea leaves,light treatment was significantly higher than that in CK1 treatment.It’s occurred a peak respectively in the withering of 1/4 and 3/4.In addition,W treatment had the lagest β-glucosidase activity than the other monochromatic ligh,followed by Y treatment.Comparison of the enzyme activity adjacent change rate under different treatments in the withering process,Y treatment showed greatest.PPO activity showed an upward trend in light withering process.It can be significantly improved by LED light treatment compared with CK1 treatment,and there appeared peaks in the wither 1/2.In addition,W treatment has the lagest PPO activity than the others,followed by R treatment.Comparison of the enzyme activity adjacent change rate under different treatments in the withering process,Y treatment showed the greatest.3.The physical and chemical ingredients changes of Tieguanyin with different LED monochromatic lighs witheringLeaf temperature can be rapidly improved by LED light treatment,having significant difference compared with dark treatment,also W treatment has the biggest leaf temperature.The water loss rate of W treatment was the fastest.For moderate withering time,CK1 treatment spent more about 1 hour than LED light treatment.Compared with dark treatment,LED light treatment significantly increased water extract,amino acid,soluble sugar,soluble protein content of withering leaf.In a word,LED blue,white and yellow light treatment are conducive to the formation of chemical quality of withering leaf.4.The enzyme activity changes of Tieguanyin with different LED combined light witheringLED light treatment can rapidly improved p-glucosidase activity,and there was a significant difference between CK and light treatment;The β-glucosidase activity in the withering process appeared two peak(withering process of 1/4 and 3/4),β-glucosidase activity of WY treatment was the highest,followed by WB treatment;Comparison of the enzyme activity adjacent change rate under different treatments in the withering process,WY treatment showed the greatest.followed by WB treatment.PPO activity showed an upward trend in light withering process.It can be significantly improved by LED light treatment compared with CK1 treatment in fresh tea leaves,and there appeared peaks in the wither 1/2.In addition,RY treatment has the lagest PPO activity than the others,followed by BY treatment.Comparison of the enzyme activity adjacent change rate under different treatments in the withering process,WB treatment showed the greatest.followed by WY treatment.5.The physicochemical compositions changes of Tieguanyin with different combinations of factors witheringThe temperature of withering leaf can be rapidly increased under different combinations of LED lights.The difference of temperature is 1℃ to3℃.Among them,the water loss of leaves in WB treatment was the fastest,followed by WR;Based on principal component analysis,the quality of wilting leaves under WB treatment and WY treatment were better than other LED combination lights.6.The aroma and quality of Tieguanyin with different combinations offactors witheringThe aroma quality rankings of Tieguanyin with different treatment were:CK<Al<B2<A3<B3<C1<A2<C3<C2<B1,the aroma quality of B1(2WBY,150μmol.m-2.s-1,1h)was best,aroma quality of Tieguanyin with light withering was better than CK treatmen.The sensory evaluation score of Different withering treatment Tieguanyin were as follows:CK<A1<B2<A3<C1<A2<B3<C3<C2<B1,Score in 91.7～82.9,B1 treatment quality score was the highest(90.7),C2(LED3WBY,50μmol.m-2.s-1,2h)treatment quality score was 89.55,ranked second.