18B-15 |
|
H.-S. SEO, Dept. of Food Science and Nutrition, Seoul National Univ., San 56-1, Shillim-Dong, Gwanak-Gu, Seoul, 151-742, South Korea and I. Hwang, Dept. of Food Science and Nutrition, Seoul National Univ., San 56-1, Shillim-Dong, Gwanak-Gu, Seoul, 151-742, South Korea. Coffee beverages have been widely consumed throughout the world for many centuries because of their attractive aromas, tastes, and physiological effects. In addition, several studies demonstrated that coffee had antioxidant activities. The differences of antioxidant activities depending on roasting degree and origin have been reported, but the change of antioxidant activity during storage has never been studied so far. Therefore, the objective of this study was to examine changes in total phenolic content and antioxidant activity of coffee with different roasting degree (light, medium, and dark) during storage. Especially, effects of roasting degree and storage temperature were focused on. The total phenolic content was determined according to the Folin-Ciocalteu method. Antioxidant activities of coffee were evaluated by measuring by DPPH free radical scavenging activity and chemiluminescence assay using luminometer. There were decreases in total phenolic content and antioxidant activity over storage, although there were increases at the first stage of storage. The loss ratio of radical scavenging activity of dark roasted coffee(55.35%) was higher than that of medium and light roasted coffee(36.40% and 34.51%, respectively) over storage. Moreover, there was a significant correlation between the estimated total phenolic contents and antioxidant activities (the DPPH assay; r:0.69, P<0.01 and chemiluminescence assay; r:0.71, P<0.01). However, there were no significant differences of total phenolic content and antioxidant activity according to the storage temperature. These results show that the total phenolic content and antioxidant activity of the darker roasted coffee are more rapidly decreased. Therefore, the shelf life of the darker roasted coffee should be more shortened in respect of antioxidant activity.
Session 18B, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |