Analysis of volatile compounds in rooibos tea (Aspalathus linearis) using different extraction methods and their relationship with human sensory perception

• Published in: Food research international 2021-03, Vol.141, p.109942-109942, Article 109942
• Main Authors: Song, Nho-Eul, Kim, Mina K., Lee, Kwang-Geun, Jang, Hae Won
• Format: Article
• Language: English
• Subjects: Descriptive sensory analysis; Gas chromatography–mass spectrometry; Rooibos tea; Simultaneous distillation–extraction; Steam distillation under reduced pressure; Volatile analysis
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2020.109942

[Display omitted] •Volatile compounds of rooibos tea were extracted by SDE and DRP.•SDE and DRP revealed 26 and 25 aroma-active compounds, respectively.•DRP was more effective than SDE for recovering compounds with high volatility.•‘Wet-wood’ and ‘green-grassy’ were the main sensory terms of rooibos tea. This study aimed to comparatively analyze the volatile flavor of rooibos tea (Aspalathus linearis) obtained by two commonly used flavor extraction methods, simultaneous distillation–extraction (SDE) and steam distillation under reduced pressure (DRP). The tea obtained by the two extraction methods, were analyzed by gas chromatography–mass spectrometry to identify volatile aroma-related compounds. Descriptive sensory analysis of the extracted rooibos tea flavor was carried out by a trained panel (n = 7). Fifty volatile compounds were identified, including 26 and 25 aroma-active compounds by SDE (45.9 µg/g) and DRP (37.5 µg/g), respectively. SDE recovered larger quantities of alcohols, acids, and esters, whereas DRP was useful for analyzing thermally unstable volatile compounds, including various alcohols, aldehydes, and hydrocarbons. Descriptive sensory analysis revealed that ketones and phenolic compounds may be responsible for the sensory attributes woody and grassy green, whereas the aldehydes and acidic compounds may contribute to floral and fruity.