Impact of steam-treatment on shelf-life stability of a xanthone-rich green herbal tea (Cyclopia maculata Andrews Kies) - identifying quality changes during storage.

BACKGROUND Steam treatment of shredded, fresh C. maculata (honeybush) plant material improves the aroma of this green herbal tea with a slight impact on color and phenolic content, but the effect on storage stability is not known. RESULTS Steam-treated (60 s before drying) and untreated (control) dried plant material was stored under normal storage conditions in semi-permeable sachets at 25 degrees C and 60% relative humidity. Reference samples of treated (steamed) and untreated (control) material were stored at 0 degrees C in impermeable pouches for maximum retention of quality. The stability of the herbal tea was assessed in terms of sensory profile, phenolic composition and color over a storage period of 6 months. Normal storage conditions resulted in a significant (P < 0.05) decrease in green color, especially in steamed samples. Intensities of fruity and sweet-associated aroma attributes increased progressively during storage, while the opposite was observed for vegetal and cereal-like attributes. These changes in the aroma profile were more pronounced in untreated (control) samples. Individual phenolic content remained stable during storage. CONCLUSIONS Storage of 3 to 6 months may result in a more appealing aroma profile and enhanced product quality, despite loss of green color. (c) 2018 Society of Chemical Industry