Effect of Different Drying Methods on Chemical Composition and Antimicrobial Activity of Bush Tea (Athrixia phylicoides)

The effect of different drying methods; sun, freeze, shade and oven drying on total polyphenol content, tannins, total antioxidants and phytochemicals content of bush tea (Athrixia phylicoides DC.) were evaluated. Assessment of minimum inhibitory concentration (MIC) assay was also done on bush tea samples. Results showed that different drying processes significantly affected phytochemical compositions of bush tea. Highest total phenolic content (8.34 mg/100 g) sample was found on freeze and shade dried bush tea compared to less than (6.50 mg/100 g) in sun or oven dried samples. Similar response was shown in total antioxidants with shade (0.628 mu mol/g) and freeze (0.626 mu mol/g) drying having significantly highest content of total antioxidants as compared to sun (0.440 mu mol/g) and oven (0.444 mu mol/g) dried samples. MIC values falls within 3.1 to 6.3 mg/mL with gram-positive bacteria being more vulnerable to the inhibitory effect of extract regardless of bush tea drying method than gram-negative. Anti-microbial activities of bush tea observed in this study will be useful to develop tea extracts for deterrence of diseases causing microorganisms hence shade drying methods will provide easy drying bush tea samples which can be adopted by farmers for commercial purposes. (C) 2014 Friends Science Publishers