Phenolic Composition of Honeybush and Changes During Herbal Tea and Extract Production

Abstract

AbstractSeveral Cyclopia species, including C. intermedia, C. subternata, and C. genistoides, are used to make honeybush tea. All species belonging to this genus (Family: Fabaceae) are endemic to the Cape Floristic region of South Africa. The various species differ in terms of their phenolic profiles, but mangiferin, isomangiferin, and hesperidin are ubiquitous to Cyclopia species. The use of conventional honeybush tea, which requires high-temperature oxidation for its characteristic aroma, flavor, and color development, predates 1900, but research on propagation, cultivation, plant breeding, processing, and product development began only in the mid-1990s. While high-temperature oxidation is integral to the production of conventional honeybush tea, this step substantially reduces the phenolic content of the plant material. The compounds are affected to varying degrees, and several, including the xanthone, mangiferin, and the dihydrochalcone, 3′,5′-di-β-D-glucopyranosyl-3-hydroxyphloretin, are very labile. Chemical reactions during heating of the plant material or extracts include cyclization, dimerization, isomerization, and epimerization, depending on the phenolic compound. Their degradation during the production of conventional honeybush tea prompted the development of green honeybush to provide the market with a tea containing significantly higher levels of phenolic compounds. The main topics of this chapter are the preparation of phenolic-rich extracts from green honeybush and the quantitative changes in phenolic composition with processing and storage of the tea and its value-added products. These include spray-dried extract powder as a food ingredient, as well as “instant” powders and ready-to-drink beverages as final consumer products.KeywordsCyclopia spp.FabaceaeHoneybushHerbal teaFood ingredientsPolyphenolsFlavonoidsProcessing