蒸青绿茶浓缩液加工过程中香气成分变化研究

Changes of aroma components in the processing of steamed green tea concentrate

中文关键词:  绿茶  香气组分  顶空固相微萃取-气相色谱-质谱联用技术

英文关键词:green tea  aroma components  headspace solid-phase micro-extraction-gas chromatography- mass spectrometry

中文摘要:

      目的 探索蒸青绿茶浓缩液加工过程中各阶段香气成分变化, 优化加工工艺。方法 采用顶空固相微萃取法(headspace solid-phase microextraction, HS-SPME)提取各加工阶段试样的香气成分, 并用气相色谱-质谱联用法(gas chromatography-mass spectrometry, GC-MS)对其进行分析, 同时对各试样进行感官评定。结果 经分析鉴定, 各阶段共鉴定出25种香气成分, 其中醇类3种、醛类11种、酮类5种、烯类2种、其他类4种。原茶叶的香气组分以β-紫罗酮、二甲硫、D-柠檬烯、癸醛、β-环柠檬醛、己醛等为主, 香气青香带栗香。浓缩灭菌后浓缩液的香气组分以芳樟醇、D-柠檬烯、癸醛、β-环柠檬醛、二甲硫、σ-杜松烯等为主, 香气栗香为主带花香和青香。醇类和烯类相对含量增加, 醛类、酮类和其他类香气组分相对含量降低, 其中醇类增幅最大25.89%, 醛类降幅最大, 降低18.09%。在各香气组分中芳樟醇相对含量增加最多25.41%, 其次σ-杜松烯、癸醛等, β-紫罗酮的相对含量降低最多, 下降9.85%, 二甲硫其次, 下降5.42%。结论 由原茶叶到浓缩液香气类型由青香带栗香变为栗香带青香花香, 香气强度减弱, 香气持久性增强。在加工过程中对浓缩液香气变化影响最显著的工艺是提取和浓缩, 各香气组分相对含量的变化是浓缩液与原茶叶香气差异的主要原因。

英文摘要:

      Objective To explore the changes in aroma components at various stages in the processing of steamed green tea concentrates, and optimize the processing. Methods The aroma components of the samples at each processing stage were extracted by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry (HS-SPME-GC-MS), and the samples were subjected to sensory evaluation. Results After analysis and identification, a total of 25 aroma components were identified, including 3 kinds of alcohols, 11 kinds of aldehydes, 5 kinds of ketones, 2 kinds of olefins and 4 kinds of other types. The aroma components of the original tea were mainly β-ionone, dimethyl sulfide, D-limonene, furfural, β-ring citral, hexanal, etc., and the aroma was green and fragrant. The main aroma components of the concentrated and sterilized solution were mainly linalool, D-limonene, furfural, β-ring citral, dimethyl sulfide, σ-jussonene, etc., and the aroma was mainly composed of floral and green scent. The relative content of alcohols and alkenes increased, and the relative content of aldehydes, ketones and other aroma components decreased. Among them, the maximum increase of alcohol was 25.89%, and the decrease of aldehydes was the largest, which was 18.09%. The relative content of linalool increased by 25.41% in each aroma component, followed by σ-juniperene, furfural, etc., the relative content of β-ionone decreased the most, decreased by 9.85%, followed by dimethyl sulfide, decreased by 5.42%. Conclusion From the original tea to the concentrated tea, the aroma type changes from green fragrant chestnut to chestnut scent with green scent, the aroma intensity is weakened, and the persistence of aroma is enhanced. The most significant processes affecting the aroma change of the concentrate during the processing are extraction and concentration. The main reason for the difference between the concentrated tea and the original tea aroma is the change of the relative content of each aroma component.