title: Effects of brewing conditions on the antioxidant capacity of twenty-four commercial green tea varieties.
abstract: A novel paper-based Nanoceria Reducing Antioxidant Capacity (NanoCerac) assay for antioxidant detection (Sharpe, Frasco, Andreescu, & Andreescu, 2012), has been adapted for the first time as a high-throughput method, in order to measure the effect of brewing conditions and re-infusion on the antioxidant capacity of twenty-four commercial green teas. The oxygen radical absorbance capacity (ORAC) assay, frequently applied to complex foods and beverages, was used as a comparator measure of antioxidant capacity. A novel measure of sustained antioxidant capacity, the total inherent antioxidant capacity (TI-NanoCerac and TI-ORAC) was measured by infusing each tea six times. Effects of brewing conditions (temperature, brew time, etc.) were assessed using one popular tea as a standard. Both NanoCerac and ORAC assays correlated moderately (R(2) 0.80 ± 0.19). The average first-brew NanoCerac, TI-NanoCerac, first-brew ORAC and TI-ORAC were: 0.73 ± 0.1 GAE/g tea; 2.4 ± 0.70 mmolGAE/g tea; 1.0 ± 0.3 mmolTE/g tea and 2.1 ± 0.71 mmolTE/g tea respectively. Brewing conditions including water temperature and infusion time significantly affected antioxidant capacity. The high-throughput adaptation of the original NanoCerac assay tested here offered advantages over ORAC, including portability and rapid analysis.
authors: Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, United States; State University of New York at Canton, 34 Cornell Drive, Canton, NY 13617, United States.
authors: Erica
authors: E
authors: Sharpe
authors: Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, United States.
authors: Fang
authors: F
authors: Hua
authors: Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, United States.
authors: Stephanie
authors: S
authors: Schuckers
authors: Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, United States.
authors: Silvana
authors: S
authors: Andreescu
authors: National College of Natural Medicine, 049 SW Porter St., Portland, OR 97201, United States. Electronic address: rbradley@ncnm.edu.
authors: Ryan
authors: R
authors: Bradley
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D001628:Beverages / Q000032:analysis*; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D013662:Tea
keywords: Antioxidant; Bagged; Brewing conditions; Camellia sinensis; Catechin; Green tea; Growing location; Harvest season; Loose leaf; NanoCerac; ORAC; Polyphenol; Re-infusion; Temperature; Time