Sun drying is the key technique for the quality formation of sun-dried green tea. In this study, the effect of three sun drying treatments, namely sun drying, sun drying shed and ultraviolet lamp irradiation under sun drying shed on fatty acids, volatile compounds, and sensory quality were compared. Results showed that there were totally seven fatty acids were detected, and unsaturated fatty acids account for up to about 60%. Among which, linolenic acid, and linoleic acid had higher contents. Moreover, the sun drying with the highest UV intensity led to the significant (P<0.05) degradation of unsaturated fatty acids which was 35.73%. A total of 84 volatiles were identified, among which aldehydes and alcohols were the major chemical classes. And the content of aldehydes was the highest which reached 23%-42%. The treatment of sun drying shed, ultraviolet lamp irradiation under sun drying shed and sun drying increased the contents of volatile compounds such as aldehydes by 50%, 112% and 205%, respectively, compared with rolled leaves. In summary, in the treatment with higher UV intensity, the changes showed a good trend. This study provides a theoretical basis for artificially simulating the drying of sun-dried green tea and which help to improve the existing sun-drying shed technology.
KUN Jirui
,
YAN Jingna
,
SHU Na
,
LIAO Xueli
,
TONG Huarong
. Effect of different sun drying techniques on fatty acids, volatile compounds and sensory quality of green tea[J]. Food and Fermentation Industries, 2020
, 46(21)
: 154
-160
.
DOI: 10.13995/j.cnki.11-1802/ts.024596
[1] LIN J K,LIN C L,LIANG Y C,et al.Survey of catechins,gallic acid,and methylxanthines in green,oolong,pu-erh,and black teas
[J].Journal of Agricultural and Food Chemistry,1998,46(9):3 635-3 642.[2] 王登良,张灵枝,毛明辉,等.不同光波晒青对单枞茶品质的影响[J]. 食品与生物技术学报,2006,25(2):56-59.
[3] WILLSON K C,CLIFFORD M N.Tea:Cultivation to consumption[J]. Ecology of Freshwater Fish,1992,5(4):175-182.
[4] 廖书娟, 童华荣.不同茶树品种脂肪酸和糖苷类香气前体分析[J].西南大学学报(自然科学版),2008,30(8):62-66.
[5] RAVICHANDRAN R,PARTHIBAN R.Lipid occurrence,distribution and degradation to flavour volatiles during tea processing[J]. Food Chemistry,2000,68(1):7-13.
[6] HO C T,ZHENG X,LI S M,et al.Tea aroma formation[J].Food Science and Human Wellness,2015,4(1):9-27.
[7] TAKEO T,TSUSHIDA T.Changes in lipoxygenase activity in relation to lipid degradation in plucked tea shoots[J].Phytochemistry,1980,19(12):2 521-2 522.
[8] 肖凌,毛世红,童华荣.3种香型凤凰单丛茶挥发性成分分析[J].食品科学,2018,39(20):244-250.
[9] PIGGOTT J R.Selection of terms for descriptive analysis[M].New York:Marcel Dekker,1991:339-351.
[10] 马惠民,王雪,钱和,等.脂肪氧合酶在茶叶中的作用[J].食品科技,2012,31(4):40-43.
[11] OKAL A W,OWUOR P O,KAMAU D M,et al.Variations of fatty acids levels in young shoots of clonal tea with location of production and nitrogenous fertilizer rates in the Kenya highlands[J].Journal of Agricultural Science & Technology,2012,14(3):1 543-1 554.
[12] 马超龙. 晒青毛茶加工过程中香气变化研究[D].重庆:西南大学,2017.
[13] ZHAO Y,YANG B,XU T,et al.Photooxidation of phytosterols in oil matrix:Effects of the light,photosensitizers and unsaturation degree of the lipids[J].Food Chemistry,2019,288(1):162-169.
[14] 张正竹,施兆鹏,宛晓春.绿茶贮藏过程中脂肪酸的变化及对香气的影响[J].中国茶叶加工,1999(2):3-5.
[15] STEWART O J,RAGHAVAN G S V,ORSAT V,et al.The effect of drying on unsaturated fatty acids and trypsin inhibitor activity in soybean[J].Process Biochemistry,2003,39(4):483-489.
[16] QIU X L,WANG J X,YU X F,et al.Aroma formation in Dianhong black tea:Effects of baking[J].International Journal of Food Properties,2017,20(11):2 724-2 735.
[17] 张灵枝,陈维信,王登良,等.不同干燥方式对普洱茶香气的影响研究[J].茶叶科学,2007(1):71-75.
[18] YANG Z Y,BALDERMANN S,WATANABE N.Recent studies of the volatile compounds in tea[J].Food Research International,2013,53(2):585-599.
[19] LIN X,ZHANG L,LEI H,et al.Effect of drying technologies on quality of green tea[J].International Agricultural Engineering Journal,2010,19(3):30-37.
[20] WHITFIELD F B,MOTTRAM D S.Volatiles from interactions of Maillard reactions and lipids[J].Critical Reviews in Food Science and Nutrition,1992,31(1-2):51-58.
[21] FRANKEL E N.Lipid oxidation[J].Progress in Lipid Research,1980,19(1-2):1-22.
