Effects of decaffeination process on the phenolic content and antioxidant capacity of brewed coffees

Abstract

Coffee is rich in phenolics which provide its color, taste and antioxidant capacity, although decaffeination may reduce coffee health benefits. Decaf methods, i.e. Swiss water (SW), supercritical CO2 (SCC), water:ethyl acetate(WEA), methylene chloride(MC), and water (H2O), may alter phenolic content, antioxidant capacity and health benefits. Decaf coffees were compared to regular caffeinated coffees (RC) of the same brand, bean, and roast. Phenolic content was measured in gallic acid equivalents (GAE in mg/L), RC: 143±2, SCC: 131±5, WEA:137±4, H2O: 146±5, MC 124±3, and SW 128±3(LSM ± SE). GAE of MC and SW were significantly lower than RC, whereas SCC, WEA, and H2O decaf methods did not affect GAE. Human LDL oxidation was induced with 10μM Cu++ in vitro and quantified (A234nm lag‐time) as % control in the presence/absence of diluted coffee. At 1:5,000 RC, SW, SCC, WEA, MC and H2O were protected LDL from oxidation vs control LDL oxidized without coffee. Antioxidant effects were less robust vs control at 10K and 50K dilutions. 5K dilutions of WEA, H2O, and MC had similar antioxidant capacities to RC, while SW and SCC were less than RC. TBARS confirmed RC and decaf coffee (5K) antioxidant capacities. This study suggests that some decaf methods may not alter phenolic content and antioxidant capacity. Decaf methods could be an independent factor for interpreting health benefit studies of decaf coffee.Grant Funding Source: WSU Foundation