The phenolic profiles and antioxidant activity in different types of tea

Abstract

Summary Phenolics are suggested to be the major bioactive compounds responsible for the health benefits of tea. Seven types of tea were extracted using boiling water. The extraction kinetics was investigated. To more fully characterise the antioxidant profiles and possible associated health benefits of these tea types, the total water‐soluble solid content, phenolics, flavonoids, and antioxidant and antiproliferative activities were quantified. Green tea leaves (GTL) were found to have the highest phenolic content (128.7 ± 1.7 mg g−1, P < 0.05), followed by teas of decaffeinated green tea bag (dGTB), green tea bag (GTB), black tea bag (BTB), decaffeinated BTB, black tea leaves and oolong tea leaves (OTL). Among the three leaf teas, GT displayed the greatest antioxidant activity (4850.2 ± 60.7 μmol g−1, P < 0.05), followed by black tea (BT) and oolong tea (OT). As for the four bag teas, decaffeinated GT possessed the strongest antioxidant activity (4431.1 ± 335.0 μmol g−1, P < 0.05), followed by GT, BT and decaffeinated BT. The results display that phenolic/flavonoid content well correlated with antioxidant activity. Proliferation of three human cancer cells was significantly inhibited in a dose‐dependent manner after exposure to some tea extracts. This may influence consumers in selecting the type of tea and tea brewing times, exhibiting greater health benefits.

Biosorption of green and black tea polyphenols into Saccharomyces cerevisiae improves their bioaccessibility

“…TPC was found to be similar between the infusions before biosorption (BB) as shown in Table 1. Despite the fact that the obtained values fell within the ranges reported in the literature (800-2400 mg/L), several authors reported that the green (unfermented) is richer in total phenols than the black (fully fermented) tea products (Carloni et al, 2013;Yang & Liu, 2012). In fact, the TPC of commercial teas depends on several factors, including the raw materials (genotype, geographical origin, growing conditions) and the industrial processing.…”

Analysis of Antioxidant Activity, Chlorogenic Acid, and Rutin Content of Camellia sinensis Infusions Using Response Surface Methodology Optimization

“…4 mm) were 80°C and 30 min. But extraction time longer than 30 min may give rise to the oxidation of phenolics (Yang and Liu 2013) or even to lower catechin content than during 15 min of extraction (Rusak et al 2008). Komes et al (2010) reported that 15 min of extraction process (at 80°C) is the best for the extraction of total nonflavonoids and total flavonoids in loose green tea leaves.…”

Effects of alternative steeping methods on composition, antioxidant property and colour of green, black and oolong tea infusions

“…Many studies reported differences in quality and antioxidant property depending on polyphenols and bioactive compounds content of different teas (Chen et al 2012;El-Shahawi 2012;Rahim et al 2014;Zhang et al 2013) according to tea type (Bae et al 2015;Lin et al 2014a, b;Yang and Liu 2013), geographic origin (Dias et al 2014) and seasonal variation (Laddi et al 2014). Effect of infusion conditions on bioactive compounds extraction has been studied (Araújo Ramalho et al 2013;Bae et al 2015;Rusak et al 2008) showing that temperature and time are the most crucial parameters affecting polyphenol content and antioxidant capacity (Araújo Ramalho et al 2013;Damiani et al 2014).…”