Revealing the profound meaning of pan-firing of oolong tea - A decisive point in odor fate

Shu-Yen Lin; Ya-Hsin Hsiao; Po-An Chen

doi:10.1016/j.foodchem.2021.131649

Revealing the profound meaning of pan-firing of oolong tea - A decisive point in odor fate

Food Chem. 2022 May 1:375:131649. doi: 10.1016/j.foodchem.2021.131649. Epub 2021 Nov 19.

Authors

Shu-Yen Lin¹, Ya-Hsin Hsiao¹, Po-An Chen²

Affiliations

¹ Department of Horticulture and Landscape Architecture, National Taiwan University, Taipei, Taiwan.
² Plant Technology Research Center, Agricultural Technology Research Institute, Hsinchu, Taiwan. Electronic address: chenpoan@mail.atri.org.tw.

PMID: 34848093
DOI: 10.1016/j.foodchem.2021.131649

Abstract

The delicate aroma of Bao-chung tea comes from oxidation, followed by fixation in the pan-firing step. Traditionally, the timing of pan-firing has been based on odor perception by tea masters and lacks relevant scientific research. Pan-firing at three different green-note intensities and three stirring sequences was used to explore the relationship between the compositions of volatile organic compounds (VOCs) before pan-firing and in the finished tea. Pan-firing decreased green leaf volatiles and increased the ratio of terpenoid volatiles. The characteristic VOCs of the finished tea were highly related to VOCs before pan-firing (R² = 0.97). Principal component analysis revealed that the traditional judgment of the pan-firing step is based on nonanal, β-linalool, and cis- and trans-linalool oxides. The timing of pan-firing is crucial for VOCs, and VOC composition before pan-firing can be used to predict desired tea aroma.

Keywords: Aroma; Green note; Odor; Oolong tea; Panning; Processing; Volatile.

MeSH terms

Odorants* / analysis
Plant Leaves / chemistry
Tea
Terpenes
Volatile Organic Compounds* / analysis

Substances

Tea
Terpenes
Volatile Organic Compounds