Determination of Caffeine Content in Tea and Maté Tea by using Different Methods

Abstract

Caffeine-containing products have been consumed for hundreds of years for their pleasant flavor and stimulating effects. In recent years, caffeine received increasing attention in food and pharmaceutical industries, due to its pharmacological properties which comprise stimulation of the central nervous system, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. The aim of this study was to determine the content of caffeine in five types of tea (white, yellow, green, oolong, black) and two types of maté tea (green maté and roasted maté tea). The content of caffeine was determined by using four different methods: extraction with chloroform, micromethod, method with lead-acetate and high performance liquid chromatography method (HPLC-PDA). The antioxidant capacity of teas as well as of the extracted ("raw") caffeine was determined by using two methods: reactions with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS assay) and Ferric reducing antioxidant power (FRAP assay). The content of caffeine has been associated with plant origin and growth conditions, as well as processing conditions. By applying all four methods, the highest content of caffeine was determined in white tea, whereas maté and roasted maté tea were characterised with the lowest content of caffeine. Spectrophotometric micromethod has proven to be the best alternative to the HPLC method. The highest antioxidant capacity was determined in yellow tea, while the lowest was determined in roasted maté tea. In comparison to the antioxidant capacity of teas, the antioxidant capacity of extracted ("raw") caffeine is almost negligible, and does not contribute to the overall antioxidant properties of tea.

Antioxidant Capacity of Teas and Herbal Infusions: Polarographic Assessment

“…Rank of total reducing power (FRAP) as well as free radicals scavenging (ABTS, DPPH) corroborates with previous results. 30,36 On the basis of RACI the following rank of order has been found: green > yellow > black > white > oolong > mate.…”

Volatile and non-volatile compounds in green tea affected in harvesting time and their correlation to consumer preference

“…Since the Woojeon tea leaf was young and soft and its physical were chemical properties were strikingly similar with those of white tea which was harvested when the leaf was still young. It has been reported that the polyphenolic concentration, catechin content, and caffeine were higher in white tea leaf Table 4 Individual polyphenolics, methylxanthines, and total antioxidant activities of 4 green teas used in this study compared to green tea leaf when about 30 samples of each green and white tea were evaluated (Komes et al 2009). According to Komes et al (2009), caffeine content was also higher in white tea compared to other Camellia sinensis based tea including green tea, oolong tea, and black tea.…”

“…It has been reported that the polyphenolic concentration, catechin content, and caffeine were higher in white tea leaf Table 4 Individual polyphenolics, methylxanthines, and total antioxidant activities of 4 green teas used in this study compared to green tea leaf when about 30 samples of each green and white tea were evaluated (Komes et al 2009). According to Komes et al (2009), caffeine content was also higher in white tea compared to other Camellia sinensis based tea including green tea, oolong tea, and black tea. Previous work also reported the higher levels of theanine, theobromine, caffeine, and total catechin contents in earlier harvested green tea, such as Woojeon and gokwoo (Lee et al 2014).…”

Hydrated Solid Forms of Theophylline and Caffeine Obtained by Mechanochemistry

“…Caffeine is a central nervous system stimulant and theophylline is used for the treatment of asthma and chronic obstructive pulmonary disease [6,7]. Hydration of caffeine and theophylline is one of the problems which affect its physicochemical stability.…”