Identification of Aroma Composition and Key Odorants Contributing to Aroma Characteristics of White Teas.

Qin-Cao Chen,Zhi Lin,Dong-Chao Xie,Yin Zhu,Mei Chen,Han Yan,De-Jiang Ni,Meng-Qi Wang

doi:10.3390/molecules25246050

Abstract

The identification of aroma composition and key odorants contributing to aroma characteristics of white tea is urgently needed, owing to white tea’s charming flavors and significant health benefits. In this study, a total of 238 volatile components were identified in the three subtypes of white teas using headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS). The multivariate statistical analysis demonstrated that the contents of 103 volatile compounds showed extremely significant differences, of which 44 compounds presented higher contents in Baihaoyinzhen and Baimudan, while the other 59 compounds exhibited higher contents in Shoumei. The sensory evaluation experiment carried out by gas chromatography–olfactometry/mass spectrometry (GC–O/MS) revealed 44 aroma-active compounds, of which 25 compounds were identified, including 9 alcohols, 6 aldehydes, 5 ketones, and 5 other compounds. These odorants mostly presented green, fresh, floral, fruity, or sweet odors. Multivariate analyses of chemical characterization and sensory evaluation results showed that high proportions of alcohols and aldehydes form the basis of green and fresh aroma characteristic of white teas, and phenylethyl alcohol, γ-Nonalactone, trans-β-ionone, trans-linalool oxide (furanoid), α-ionone, and cis-3-hexenyl butyrate were considered as the key odorants accounting for the different aroma characteristics of the three subtypes of white tea. The results will contribute to in-depth understand chemical and sensory markers associated with different subtypes of white tea, and provide a solid foundation for tea aroma quality control and improvement.

Highlights

White tea, one of six kinds of teas in China, originates from, and is mainly produced in, the northeast of Fujian province, and has received increasing attention in China owing to its charming flavors and significant health benefits [1]
A total of 586 compounds were primarily identified as common volatile compounds after peak alignment, and the comparison of retention index (RI) and verification of standards resulted in 238 reliable volatile compounds, including 17 alkanes, 28 alkenes, Molecules 2020, 25, x FOR PEER REVIEW
As noticeable stronger aroma intensities of aroma-active compounds in most classes, especially class B, were observed in BMD compared with BHYZ and SM, in combination with sensory evaluation results of BMD, our findings indicated that some odorants in class B might be important contributors of pekoe flavor

Summary

Introduction

One of six kinds of teas in China, originates from, and is mainly produced in, the northeast of Fujian province, and has received increasing attention in China owing to its charming flavors and significant health benefits [1]. Based on the tenderness level of fresh tea leaves, white teas are generally. Numerous studies indicated that the main taste compounds in white teas are catechins and its polymers, free amino acids, caffeine, flavone, and flavonol glycosides, soluble sugars, phenolic acids, nucleosides, and nucleotides [2,3,4,5,6]. Aroma is an important factor that determines the quality of teas and affects the choice of consumers. The unique and simple processing gives white tea a green, fresh, or pekoe aroma, which gains widespread popularity among different customers. The aroma profiles of white teas have been increasingly studied [7,8], and the enantiomeric distributions of important volatile compounds [9]

Methods

Results

Discussion

Conclusion