Antioxidant activity of health tea infusions and effect of sugar and milk on in-vitro availability of phenolics in tea, coffee and cocoa drinks

The objectives of this study were to analyse the content of phenolics and antioxidant activity of some health tea and also study the effect of addition of sugar and milk on in - vitro availability of phenolics in tea, cocoa and coffee drinks Design/methodology/approach Seven brands of health tea, two brands of cocoa drink, one brand each of coffee, powdered milk and sugar were selected. The tea samples were analysed for pH, titratable acidity, total phenol and antioxidant activity using Folin-Ciocalteau and 2, 2-diphenyl-1-picryl-hydrazil (DPPH) reagents, respectively. In-vitro simulated digestion modeling stomach and small intestine were carried out on tea infusion, coffee and cocoa drinks with or without sugar and phenolic availability were analysed. Findings The result indicated that pH, titratable acidity and total phenolics ranged from 4.5 to 5.6, 0.167 to 0.837 (as maleic acid) and 1.15 to 1.17 mg/g gallic acid equivalent, respectively. Black tea recorded the highest phenolic content, in-vitro phenolic availability and antioxidant activity. Addition of sugar to black tea and chocolate drink caused a significant decrease in in-vitro available phenolics while addition of milk leads to a significant enhancement. Research limitations/implications The data obtained in this study can be used nutritionally and commercially to show the impact of adding sugar or milk on the content of phenolics and their bioavailability in-vitro. The study justifies the claim that tea could h...
Source: Nutrition and Food Science - Category: Nutrition Source Type: research