Title : Impact of harvest season on sensory and phenolic profiles of selected clones of Cyclopia subternata (honeybush)
Cyclopia subternata (honeybush) is a commercially important South African fynbos plant used as a herbal tea. Some genotypes produce a bitter-tasting tea, contrary to the “sweet, honey-like” beverage, typically associated by consumers with honeybush tea. Furthermore, this species is a rich source of bioactive xanthones, benzophenones and flavanones. The objective of this study was to determine the impact of harvest season on the sensory and phenolic profiles of selected clones of C. subternata. Sensory and phenolic profiles are second tier criteria for selection of honeybush plant material for breeding purposes. Six clones were selected, based on biomass yield and the rooting and survival of cuttings. The plant material was processed, including “fermented”, and a hot water infusion of the “tea bag fraction” subjected to sensory analysis entailing descriptive sensory analysis. Standardised protocols were followed for processing and sensory analysis. The data were analysed using univariate and multivariate statistical procedures. The phenolic content of the leaves (unprocessed) was determined by HPLC-DAD and analysed using the univariate ANOVA. The results showed that harvesting season significantly affected the phenolic content of honeybush. Harvesting in summer and winter resulted in infusions with the highest intensities of positive aroma attributes; however, no clear trend for harvest season could be established for taste modalities. The highest phenolic content was recorded in summer and autumn, whereas the opposite was evident in winter. Significant differences in terms of sensory attributes and phenolic content were observed between clones, with some clones less affected by harvesting season. The differences in harvest season and clones may guide selection of clones for breeding programmes aiming at improving herbal tea quality and/ or nutraceutical value.