Development of chemical-based reference standards for rooibos and honeybush aroma lexicons
Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The honeybush sensory wheel was revised, using a large sample set (n = 585) comprising of the major commercial Cyclopia species, i.e. C. intermedia, C. subternata and C. genistoides. Only positive and negative aroma attributes were included in the wheel. Chemicals were identified to serve as reference standards for the honeybush (Cyclopia spp.) lexicon. Similarly, chemical-based reference standards were identified for the rooibos (Aspalathus linearis) lexicon. From a comprehensive literature search and gas chromatography–mass spectrometry analyses, chemicals were screened by an expert panel for their suitability in terms of typicality of the target aroma. Each chemical was evaluated in a ‘base tea’ and compared to a specific ‘reference tea’ exhibiting a high intensity of the target aroma. A total of 30 and 44 chemicals for rooibos and honeybush, respectively, were selected for validation by a trained panel. Descriptive sensory analysis was conducted to assign typicality and intensity scores for each chemical representing a target aroma attribute. Several chemicals were identified as suitable reference standards for the following aroma notes: isophorone (‘rooibos-woody’), maltyl isobutyrate (‘caramel’), cis-3-hexenol (‘green grass’), 4-oxoisophorone (‘seaweed’) and 2,4,6-trichloroanisole (‘musty/mouldy’) for rooibos; and 2-acetyl-5-methylfuran (‘woody’), levulinic acid (‘fynbos-sweet’), maltyl isobutyrate (‘caramel’), and 2-acetylpyrrole (‘nutty’) for honeybush.
Description
CITATION: du Preez, B.V.P. et al. 2020. Development of chemical-based reference standards for rooibos and honeybush aroma lexicons. Food Research International, 127. doi:10.1016/j.foodres.2019.108734.
The original publication is available at https://www.sciencedirect.com/journal/food-research-international
The original publication is available at https://www.sciencedirect.com/journal/food-research-international
Keywords
Herbal teas -- Sensory evaluation, Aroma wheel, Quality control tools, Aroma lexicon, Chemical reference standards, Honeybush tea (Cyclopia spp.) -- Sensory evaluation, Rooibos tea -- Chemical analysis
Citation
du Preez, B.V.P. et al. 2020. Development of chemical-based reference standards for rooibos and honeybush aroma lexicons. Food Research International, 127. doi:10.1016/j.foodres.2019.108734.