Study on the Suitability of Tea Cultivars for Processing Oolong Tea from the Perspective of Aroma Based on Olfactory Sensory, Electronic Nose, and GC-MS Data Correlation Analysis

Abstract

The oolong tea aroma is shown to consist of cultivar aroma and technical aroma in this study based on the aroma differences between oolong tea products of cultivars of different suitability, as determined by correlation analysis of olfactory, sensory, electronic nose, and GC-MS data. Human senses were significantly affected by the aroma components, which included eight terpene metabolites (β-Ocimene, (Z)-Furan linalool oxide, linalool, (3E)-4,8-Dimethyl-1,3,7-nonatriene, (E)-Pyranoid linalool oxide, γ-Elemene, Humulene, (Z,E)-α-Farnesene), three carotenoid metabolites (β-Ionone, (Z)-Geranylacetone and 6-methyl-5-Hepten -2-one), three lipid metabolites ((Z)-3-Hexenyl (Z)-3-hexenoate, Butanoic acid hexyl ester, and (Z)-Jasmone), four amino acid metabolites (Methyl salicylate, Geranyl isovalerate, indole, and Phenylethyl alcohol), and six thermal reaction products (2-Pentylfuran, Octanal, Decanal, (E,E)-2,4-Nonadienal, (Z)-2-Decenal, and (E)-2-Undecenal). Meanwhile, several aroma compounds (such as (E)-Nerolidol and α-Farnesene), mainly comprising the “technical aroma” formed in the processing mode, were noted to be less closely related to cultivar suitability. This study sheds light on the aroma characteristics of different tea cultivars for oolong tea processing.

Uncovering the effect of Moringa oleifera Lam. leaf addition to Fuzhuan Brick Tea on sensory properties, volatile profiles and anti-obesity activity

“…In recent years, electronic noses and electronic tongues have been widely used for the analysis of taste, which are feasible to determine tea quality. 22,23 As shown in Fig. 1A, in principal component analysis (PCA), the first two components PC1 and PC2 accounted for 99.99% (PC1 = 99.92% and PC2 = 0.07%), indicating that the tea samples of FBT and MFBT could clearly be discriminated.…”

Biosynthesis and the Transcriptional Regulation of Terpenoids in Tea Plants (Camellia sinensis)

“…There are more than 100 types of terpenoid tea aroma substances, most of which are volatile monoterpenoids (such as geraniol and linalool) and sesquiterpenes (such as nerolidol) [ 34 , 58 ]. Studies have shown that volatile terpenes dominate the aroma (more than 60%) in tea products [ 59 , 60 ].…”

“…Generally speaking, β-myrcene, α-phellandrene, ( Z )-β-ocimene, ( Z )-furan linalool oxide, ( E )-furan linalool oxide, γ-terpinene, DMNT, cosmene, ( E )-pyranoid linalool oxide, linalool oxide pyranoside, linalyl formate, α-cubebene, γ-elemene, humulene, ( E )-β-famesene, ( Z , E )-α-farnesene, α-muurolene, α-farnesene, T-muurolol, α-cadinol, α-terpineol, geraniol, β-caryophyllen, δ-cadinene, ( E )-nerolidol, linalool, D-limonene, and β-pinene are reported to be important terpene compounds in tea aroma [ 48 , 59 , 61 ]. Among them, linalool and its furan oxides, ( Z )-furan linalool oxide and ( E )-furan linalool oxide, are important components of sweet and floral aromas, while ( E )-pyranoid linalool oxide and linalool oxide pyranoside have earthy aromas [ 62 ].…”

“…Geraniol and linalool oxides present pleasant floral scents and may be the principal contributors to the floral and green odor of Longjing tea [ 63 , 64 , 65 ]. The compound ( E )-nerolidol has floral green, citrus woody, and waxy odors [ 59 ], which are among the characteristic aromas of oolong tea [ 66 ]. The content of these terpenes varies among different tea plant species and might affect the suitability of tea cultivars, indicating that they may play a major role in the formation of floral fragrance [ 59 ].…”

Recent Applications of Potentiometric Electronic Tongue and Electronic Nose in Sensory Evaluation

“…A recent study by He et al (2022) distinguished different oolong tea cultivars. They correlated the e-nose data (FOX4000, Alpha MOS) and GC-MS with a headspace-solid phase microextraction method (HS-SPME-GC-MS) to explore the differences in aroma compounds and their effects on oolong tea cultivars suitability.…”