Comparative study of qualitative and quantitative important components in Rooibos (Aspalathus linearis), green and black tea

Resumen

A comparative study was performed of the mineral and phenolic content, as well as the total antioxidant activity (TAA) of green and black tea and rooibos infusions. An HPLC method using C18 reverse phase column with UV-Vis and mass spectrometry (MS) detection was developed to assay simultaneously caffeine, gallic acid and the major flavonoids present in aqueosu extracts. This method allows the analysis of infusions and complex infusion mixtures with very different flavonoid composition. Of the minerals tested, black and green tea and rooibos aqueous extracts were demonstrated to contain magnesium, calcium, sodium, potassium, manganese, iron and zinc. While black tea infusion showed the highest amount of magnesium, potassium and zinc, the highest calcium, iron and sodium contents were found in rooibos, and green tea presented the highest amounts of manganese. Green and black tea infusions displayed no significant differences in terms of TAA, while both showed significant differences when compared to rooibos. Although tea infusions (green and black) showed a total polyphenol content (TP) almost 50% higher than rooibos, the TAA was just 20% higher for teas. © 2009 Nova Science Publishers, Inc. All rights reserved.