Determination of the Effects of Adding Milk and Sugar on the Antioxidant Capacity of Oolong Tea by Chemical and Cell Culture-Based Antioxidant Assays
Angkana Wipatanawin, Sudarat Phongsawanit, Thadthanan Maneeratprasert, Sittiwat Lertsiri* Author for corresponding; e-mail address: angkana.s@cmu.ac.th ; s.angkana@gmail.com
Volume: Vol.42 No.3 (JULY 2015)
Research Article
DOI:
Received: 22 July 2014, Revised: -, Accepted: 27 October 2014, Published: -
Citation: Wipatanawin A., Phongsawanit S., Maneeratprasert T. and Lertsiri S., Determination of the Effects of Adding Milk and Sugar on the Antioxidant Capacity of Oolong Tea by Chemical and Cell Culture-Based Antioxidant Assays, Chiang Mai Journal of Science, 2015; 42(3): 699-711.
Abstract
The effect of sugars and/or milk on the antioxidant capacity of Oolong tea was evaluated using 2,2´-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS), ferrous ion-chelating (FIC) and cellular antioxidant activity (CAA) assays. The addition of sugar did not alter the antioxidant capacity of tea (p < 0.05), however with the addition of sweetener an 18% and 14% increase was observed using ABTS and FIC assays respectively. In contrast, using the CAA method, the sweetener decreased the tea antioxidant capacity by 8%. Milks and milks and sugars decreased the antioxidant capacity of tea by 30% and 45% respectively determined by ABTS and CAA assays, with an opposite result using the FIC method. The chemical and cellular based methods showed poorly correlated values.