THE INFLUENCE OF ASCORBIC ACID AND HONEY ADDITION ON THE ANTI-OXIDANT PROPERTIES OF FRUIT TEA INFUSIONS: ANTIOXIDANTS IN FRUIT TEA INFUSIONS

Abstract

The influence of ascorbic acid and honey addition on the total phenol (TP) content and anti-oxidant capacity of ten commercial fruit tea infusions was studied. The Folin-Ciocalteu assay was used to determine the TP content, ferric reducing anti-oxidant power assay for reducing capacity and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt assays for radical scavenging capacity. High pressure liquid chromatography was employed to quantify polyphenolic compounds in infusions. The addition of ascorbic acid (22.5 mg) increases the TP content as well as anti-oxidant capacity of all fruit tea infusions. The addition of honey (1.5 g) to infusions containing ascorbic acid resulted in an average 28% decrease in the TP value, and a significant average (22%) decrease in the DPPH radical scavenging capacity. Chlorogenic acid is the predominant phenolic acid in tested infusions (range: 12.86–91.55 mg/L), while epigallocatechin-gallate is the most concentrated among analyzed catechins (range: 19.26–161.41 mg/L). PRACTICAL APPLICATIONS There are no published scientific papers characterizing polyphenolic compounds and anti-oxidant activity of infusions prepared from bagged fruit teas, although these beverages are very popular in Europe and United States where they are often taken with lemon and honey. The results reported in this study indicate that fruit tea infusions are, just like herbal teas, valuable sources of polyphenolic anti-oxidants and that beverages prepared from teas containing a substantial portion of fruit parts exhibit the best anti-oxidant properties. Also, we have demonstrated that the addition of ascorbic acid enhances the anti-oxidant capacity of fruit teas while the addition of honey causes a decrease in the total phenol content and may adversely affect the radical scavenging potential of analyzed fruit teas.