速溶乌龙茶粉挥发性成分的分析

Volatile Components of Instant Oolong Tea Powder

摘要:

速溶茶粉是重要的茶叶深加工产品。国内外对速溶茶粉加工工艺进行了深入研究，但对其香味品质的研究较少。本文以速溶乌龙茶粉为研究对象，采用固相微萃取（SPME）结合气-质联用技术（GC-MS）研究其挥发性成分。结果表明：SPME的优化条件为用50/30 μm DVB/CAR/PDMS萃取头在70 ℃萃取40 min；经GC-MS分析，从速溶乌龙茶粉中鉴定出39种挥发性成分，其中芳樟醇、反式-β-罗勒烯、反式芳樟醇氧化物和顺式芳樟醇氧化物浓度最高，其浓度分别是16422.8、3407.8、2549.7和2163.1 μg/kg；香气强度值最高的成分是芳樟醇、顺式芳樟醇氧化物、反式芳樟醇氧化物、反式-β-罗勒烯和苯乙醛，它们的香气强度值分别是2,737,138、360,522、424,950、56,796和31,708。以上结果表明速溶乌龙茶粉主要挥发性成分和香气贡献成分是芳樟醇、反式-β-罗勒烯、反式芳樟醇氧化物和顺式芳樟醇氧化物。该研究为评价速溶茶粉香味品质特征提供了挥发性成分的数据参考。

Abstract:

Instant tea powder is an important processed product of tea. Previous studies have reported in-depth investigations regarding the processing technology used for instant tea powder, however, only few studies are available on the quality of instant tea powder. The volatile components of instant oolong tea powder were analyzed using gas chromatography-mass spectrometry (GC-MS) combined with solid-phase micro-extraction (SPME). The results showed that the optimal SPME conditions included using the 50/30-μm Divinylbenzene-Carboxen-Polydimethylsiloxane DVB-CAR-PDMS adsorption fiber at 70℃ for 40 min. GC-MS analysis identified 39 volatile components, consisting mainly of linalool, trans-ocimene, cis-linalool oxide, and trans-linalool oxide, at concentrations of 16422.8, 3407.8, 2549.7, and 2163.1 μg/kg, respectively. Based on the analysis of odor activity value (OAV), the compounds mainly contributing to the aroma and their corresponding odor activity values were: linalool, 2,737,138; cis-linalool oxide, 360,522; trans-linalool oxide, 424,950; trans-β-ocimene, 56,796; and benzene acetaldehyde, 31,708. The above results together indicated that the main volatile components and aroma contributors were linalool, trans-β-ocimene, cis-linalool oxide, and trans-linalool oxide. These results provide reference data for the evaluation of the volatile components contributing to the aroma quality of instant oolong tea powder.