Changes in quality parameters of commercial black seedling tea due to the time of the year in the Eastern Highlands of Kenya

Abstract

Significant ( P ≤ 0.05) changes in yields, rainfall and chemical quality parameters (except thearubigins) of black seedling tea with the time of the year were recorded in the Eastern Kenya Highlands. Larger variations were noted in the aroma and yields than in the plain tea quality parameters. However, the variations were less than those recorded in countries further away from the equator. The Group I volatile flavour compounds (VFC) and caffeine levels were inversely correlated ( P ≤ 0.05) with each other, while flavour index and sensory evaluation had significant ( P ≤ 0.01) correlations with rainfall. Sensory evaluation was also significantly correlated with flavour index ( P ≤ 0.001) and inversely with caffeine ( P ≤ 0.05) and Group I VFC ( P ≤ 0.01). High yields and caffeine levels in black teas were realised in the warmer months.