Influence of steeping conditions (time, temperature, and particle size) on antioxidant properties and sensory attributes of some white and green teas

Abstract

The influence of commonly used steeping times and temperatures, as well as leaf size on the antioxidant activity and sensory attributes of tea were studied. Five unblended white and green tea samples from China and Malawi, infused in hot (70 °C and 90 °C; 7 min) or cold water (room temperature: 15, 30, 60, or 120 min) either as whole leaves or as milled, were analyzed. Total phenolic and flavonoid contents as well as antioxidant power (ABTS assay) were measured. The results show that the maximum extraction efficiency occurs with cold water for 120 min and with hot water at 90 °C and that only in the case of teas from whole, large leaves, the extraction was greater in cold than in hot infusions. Moreover, tea infusions prepared from milled leaves have the greatest antioxidant activity. In the sensory evaluation of some of the tea infusions, white teas were perceived more fragrant than green ones and were judged as the most favorite by the majority of the judges, especially for the brew prepared in cold water from whole leaves; all infusions obtained from the milled leaves in fact have a more bitter and astringent taste.

Temperature and Time of Steeping Affect the Antioxidant Properties of White, Green, and Black Tea Infusions

“…The effect of extraction conditions such as time and temperature of steeping on antioxidant properties of some white and green teas was examined in a study designed by Castiglioni and others (). In line with the results of this study, they showed that the cold water for 2 h and hot water at 90 °C maximized the extraction efficiency in green and white tea.…”

“…The content of total flavnoids in the different tea extracts were significantly dependent on time of extraction and varied from 731 to 2076 (Silver Needle), from 933 to 1538 (Shou Mei), from 1050 to 1497 (Chinese green tea), from 955 to 1435 (Japanese green tea), from 1004 to 1819 (BOH black tea), and from 1040 to 1931 (Lipton black tea) mg quercetin/g dried weight. It has been suggested that the antioxidant profile of the different type of teas is affected by their different methods of production (Vinson and Dabbagh ; Castiglioni and others ; Lantano and others ; Venditti and others ).…”

Comparison of optimal temperature and time conditions for highest a-glucosidase inhibitory activity from various of Korea mulberry teas

“…Generally, green tea active ingredients, caffeine and polyphenols, are usually isolated from raw material by extraction on 70°C (Castiglioni et al, 2015). So, optimal temperature condition of mulberry tea also based on 70°C for α-glucosidase inhibitory activity.…”

“…Several factors regarding the extraction process have been shown to influence the functional materials in tea preparations, including: temperature, type of tea, concentration of tea, and steep time (Astill et al, 2001;Castiglioni et al, 2015). A general consumer is unlikely to monitor the exact amount of …”

Effect of consecutive steeping on antioxidant potential of green, oolong and black tea

“…It was observed that caffeine, catechins and gallic acid content was the highest in first infusion and decreased gradually in later infusions in all types of teas (Yang et al ., ), and a similar study showed no major difference in catechins content in between first infusion and second infusion, but the third infusion showed decline (Sharma et al ., ). It was also reported that the degree of processing or fermentation plays an important part in influencing the catechins, phenolic acid and caffeine content of tea along with other factors such as species, horticultural condition, steeping time and temperature (Zuo et al ., ; Yang et al ., ; Carloni et al ., ; Castiglioni et al., ). The public has no general idea about the outcome of consecutive steeping on the whole leaf teas in terms of its antioxidant potential and health benefits.…”