Naslov
Phenolics and antioxidant activity of green, yellow and black tea infusions

Autori
Kopjar, Mirela ; Šaravanja, Marija ; Piližota, Vlasta

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of abstracts: 8th International congress of food technologists, biotechnologists and nutritionists / Frece, Jadranka - , 2014

Skup
8th International congress of food technologists, biotechnologists and nutritionists

Mjesto i datum
Opatija, Hrvatska, 21.10.2014. - 24.10.2014

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
antioxidant activity; green; yellow and black tea infusions; phenolics

Sažetak
Tea is one of the most consumed beverages around the world. There is growing evidence that tea polyphenols can reduce the risk of heart diseases and cancer in humans and also tea has been associated with antiallergic action and antimicrobial properties. In this work, influence of time and temperature of maceration of green, yellow and black tea on content of phenolics, flavonoids, tannins and antioxidant activity of tea infusion were investigated. Maceration time of tea was 3 and 5 minutes and maceration temperatures of tea were 70 and 90 °C. Influence of repeated maceration of the same samples, on mentioned parameters, was also investigated. Content of phenolics, flavonoids and tannins highly depended on maceration time and temperature. The highest values of evaluated parameters were obtained after maceration for 5 minutes at 90 °C. Compering results at those conditions, the highest phenolic content had yellow tea (93.74 mg GAE/100 mL) while green and black tea had similar content (56.27 and 56.77 mg GAE/100 mL, respectively). After repeated maceration, lower values of evaluated components were obtained. After second maceration phenolic contents were lower for 43 to 78 %, and after third maceration from 71 to 90%, depending on tea and maceration time and temperature. Antioxidant activity was determined by application of ABTS+˙ and DPPH˙ free radicals. The highest antioxidant activity was determined in yellow tea, 2.1 and 1.1 µmol/100 mL for ABTS and DPPH, respectively. In all samples ABTS values were higher due to lower selectivity of these free radicals. Results of our research showed importance of conditions during preparation of tea infusions since by them we can highly influence on maceration of phenolics from tea to tea infusions.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

POVEZANOST RADA