Non-targeted metabolomic analysis reveals the mechanism of quality formation of citrus flower-green tea.

Abstract

Citrus flower-green tea (CT) is a scented tea processed from green tea (GT) and fresh citrus flower, which is favored by consumers due to its potential health benefits and unique citrus flavor. This study evaluated the quality of CT and revealed the mechanism of its quality formation. The CT had a significant citrus flavor and a good antioxidant activity, and its sensory quality was superior to that of GT. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis revealed that the scenting process resulted in a significant increase of alkenes such as β-pinene, trans-β-ocimene, α-farnesene, isoterpinolene, and γ-terpinene, as well as a significant decrease of alcohols such as α-terpineol, l-menthol, and linalool in CT in comparison with GT. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed that the levels of flavonoids (such as neohesperidin, hesperidin, tangeritin, hesperetin 5-O-glucoside, and nobiletin) and alkaloids (such as trigonelline and theobromine) in CT increased significantly after scenting process, while the levels of amino acids (such as valine and l-phenylalanine) and organic acids (such as ascorbic acid) decreased significantly. These observations showed that the scenting process promoted the absorption of aroma from citrus flowers by GT and the changes in its non-volatile metabolites, leading to the formation of citrus flavor quality in CT. © 2024 Society of Chemical Industry.