The Phenolic Composition and Antioxidant Activity of Tea with different Parts of <i>Sideritis</i><i> </i><i>condensate</i><i> </i>at Different Steeping Conditions

Abstract

Tea with different parts (flower, leaf, seed) of Sideritis condensate infused at different temperatures (60 and 100°C) and times (5, 10 and 30 minutes) were assessed for their phenolic composition and antioxidant activities. Leaf tea had the highest total phenolic content where as seed tea had the lowest.Leaves soaked at 100°C for 10 minutes had the highest total phenolic content. Total phenolic content of flower tea increased with increase in extraction temperature and time. Radical scavenging activities of leaves infused at 60°C for 5, 10 and 30 minutes were statistically in the same group but lower than those of leaves soaked at 100°C for 5, 10 and 30 min. The major phenolic compound identified from almost all aqueous infusions was the p-coumaric acid. The conditions of tea prepared from leaves of the Sideritis condensata at 100°C for 5, 10 and 30 minutes are the most appropriate conditions in regard to extraction of the highest total phenolics and the strongest antioxidant activity.

Effect of location on some physico‐chemical properties of prickly pear (Opuntia ficus‐indicaL.) fruit and seeds

“…Determination of phenolic compounds were done by High Performance Liquid Chromatography (HPLC; Shimadzu LC 10A vp, Kyoto, Japan) according to Kara, Şahin, Turumtay, Dinç, and Gümüşçü (). Standards used in the analysis are gallic acid, 3,4‐dihydroxybenzoic acid, catechin, 1,2‐dihydroxybenzene, syringic acid, caffeic acid, rutin, p ‐coumaric acid, trans ‐ferulic acid, apigenin 7‐glucoside, resveratrol, quercetin, trans ‐cinnamic acid, naringenin, campherol, and isorhamnetin (Sigma‐Aldrich, Steinheim, Germany).…”

Biochemical Fingerprint of Greek Sideritis spp.: Implications for Potential Drug Discovery and Advanced Breeding Strategies

“…Air dried plant materials were ground to a fine powder with a grinder. Tea infusions were prepared according to Kara et al [22]. Briefly, 1 gr of dry material was soaked in boiled water for 5 min.…”

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“…A decrease in antioxidant activity was found in thermal processed brewed of aloe vera skin dried at 70-90°C for 1 to 5 minutes. Kara et al (2014) reported that radical scavenging activities of Sideritis condensate of aqueous extract at 60°C for 5, 10 and 30 minutes were statistically in the same group but lower than those of leaves soaked at 100°C for 5, 10 and 30 min. Su et al (2007) also noted that higher temperature and longer time led to the loss of antioxidant activity of oolong tea.…”

“…And this result is similar to one reported by Braud et al (2015), who found the phenolic content will decrease around 10% during thermal processing for 5 to 30 minutes. Kara et al (2014) also noted that the increased of thermal processing could decrease phenolic content at a different temperature and time. Astill et al (2001) suggested that the most of the compound in tea brewed such as polyphenol, caffeine, tannin and theaflavin content will reduce cause of the increasing of temperature and time.…”