郭向阳, 霍羽佳, 王本友, 宛晓春. 采用气相色谱-离子迁移谱分析黄大茶加工过程挥发性成分[J]. 农业工程学报, 2021, 37(6): 274-281. DOI: 10.11975/j.issn.1002-6819.2021.06.033
    引用本文: 郭向阳, 霍羽佳, 王本友, 宛晓春. 采用气相色谱-离子迁移谱分析黄大茶加工过程挥发性成分[J]. 农业工程学报, 2021, 37(6): 274-281. DOI: 10.11975/j.issn.1002-6819.2021.06.033
    Guo Xiangyang, Huo Yujia, Wang Benyou, Wan Xiaochun. Analysis of volatile compounds in large-leaf yellow tea during manufacturing processes using gas chromatography-ion mobility spectrometry[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(6): 274-281. DOI: 10.11975/j.issn.1002-6819.2021.06.033
    Citation: Guo Xiangyang, Huo Yujia, Wang Benyou, Wan Xiaochun. Analysis of volatile compounds in large-leaf yellow tea during manufacturing processes using gas chromatography-ion mobility spectrometry[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(6): 274-281. DOI: 10.11975/j.issn.1002-6819.2021.06.033

    采用气相色谱-离子迁移谱分析黄大茶加工过程挥发性成分

    Analysis of volatile compounds in large-leaf yellow tea during manufacturing processes using gas chromatography-ion mobility spectrometry

    • 摘要: 茶叶加工对茶叶香气的形成至关重要。为了研究黄大茶加工过程中香气成分的组成及变化规律,采用气相色谱-离子迁移谱(Gas Chromatography-Ion Mobility Spectrometry,GC-IMS)技术对黄大茶加工过程的挥发性成分进行分析。定性分析、鉴定茶叶挥发性成分,构建黄大茶加工过程挥发性成分的差异谱图,并以鉴定的挥发性成分对黄大茶加工过程进行主成分分析。共鉴定出挥发性成分40种,主要有醇类、酮类、醛类、酯类和杂环类化合物。杂环类和醛类化合物是黄大茶挥发性成分的主体部分,且杀青之后,杂环类化合物的含量随着加工过程的进行逐渐增加,醛类化合物的相对含量在初烘之后呈现显著性增加,而醇类及酮类挥发性成分的相对含量在初烘之后显著性降低(P<0.05)。具花香的氧化芳樟醇只在初闷之前的样品中得到鉴定,在鲜叶中的含量最高,达21.98%,而1-辛烯-3-酮及苯乙酮只在初烘之后的样品中得到鉴定。通过GC-IMS的指纹图谱可知,苯甲醛、2,5-二甲基呋喃、糠醛及二甲基二硫等挥发性成分构成了经"拉老火"工序的黄大茶的特征峰区域。在一定程度上,主成分分析能够将黄大茶加工过程样品进行区分,表明气相色谱-离子迁移谱分析可为黄大茶加工过程的判别区分提供可能。相较于传统的茶叶挥发性成分检测分析技术,气相色谱-离子迁移谱具有快速、高效、绿色环保的特点。研究结果提供一种新的茶叶挥发性成分的检测分析方法,同时为茶叶加工过程监测及品质控制等提供了一定参考依据和理论基础。

       

      Abstract: Abstract: Large-leaf yellow tea (LYT) is a classical beverage with a unique caramel taste similar to the fried rice flavor in Asian areas. LYT processing substantially determines the quality grade of tea, volatile composition, and aroma profile. However, the aroma property and volatile compounds of LYT still remain unclear during processing. This study aims to clarify the volatile compositions and variations in the processing of LYT using the gas chromatography-ion migration spectrometry (GC-IMS), coupled with principal component analysis (PCA). The reason was that the GC-IMS technology was characterized by fast, simple, efficient, and environmentally friendly. A total of 40 volatile compounds were identified, including alcohols, ketones, aldehydes, esters, and heterocyclic compounds. Among the identified volatile compounds, the main volatile compounds in LYT were heterocyclic compounds and aldehydes. Moreover, the relative numbers of heterocyclic compounds increased significantly with the process of tea after fixing treatment. Meanwhile, the relative content of aldehydes enhanced dramatically, whereas those of alcohols and ketones compounds decreased remarkably after primary roasting. In addition, the linalool oxide (trans-furanoid) with floral odor was only identified in the previous samples with primary roasted treatment, where the highest relative amount accounted for 21.98 % of the total found in fresh tea leaves (FTL). The 1-octen-3-one and acetophenone were only identified in tea samples after primary roasted processing. Furthermore, the differential profiles and chromatographic fingerprint of LYT during processing were established using the volatile compounds detected by GC-IMS technology. The characteristic chromatographic regions consisted of benzaldehyde, 2,5-dimethylfuran, furfurol and dimethyl disulfide in the full-fire processing of LYT. A PCA analysis was performed on the identified volatile compounds to further distinguish LYT processes, where the accumulated contribution rate of the first two principal components (PC 1 for 65.0 %, PC 2 for 15.5 %) was 80.5 %, indicating that the GC-IMS was useful to discriminate the LYT samples of different processes. The tea samples were separated according to the processes, where there was a far distance between FTL and LYT, indicating that the tea processing was vitally important to the formation of aroma characteristics of LYT. The findings can provide new insight into the determination of volatile compounds for better monitoring process and quality control of tea.

       

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