Antioxidant activity and total polyphenol content of coffee extracted by three extraction methods
Eight kinds of Arabica coffee beans were extracted using solid-liquid (SLE), espresso (ESE), and coffee maker (CME) extractions. The antioxidant activity by DPPH assay and total polyphenol content (TPC) were significantly lower in ESE compared to the other two extracts (p < 0.05). In FRAP assay, CME was significantly higher in the antioxidant activity then those of SLE and ESE (p < 0.05). The antioxidant activity TPC of CME was significantly higher than those of SLE and ESE (p < 0.05). Of the eight kinds of coffee beans, there was no distinctive trend in the highest and the lowest amounts of antioxidant activity and TPC within each extraction method. CME was the most efficient method in extracting functional materials in coffee which might be due to the higher amount of water used for extraction.
Coffee, one of the major commodities being traded all over the world (1), is considered as a hedonic food. Consumers tended to focus on the favors of coffee rather than their functionality. However, coffee contains significant amounts of functional compounds such as caffeic, chlorogenic, hydroxycinnamic, ferulic, sinapic acids (2-5), and melanoidins (6, 7) that have strong antioxidant activity. Coffee is known as a major source of chlorogenic acids for human diet (8, 9). Coffee is also known as a major source of antioxidants in European countries (10, 11). Many studies reported the functionality of coffee is influenced by the degree of roasting (12), varieties (13), or roasting methods (14). Although solid-liquid extraction (SLE) had been used in many scientific studies (13-15), espresso extraction (ESE) and coffee maker extraction (CME) are the most common methods for extracting coffee. It was unknown whether the antioxidant activity and total polyphenol content (TPC) of coffee extracted by the SLE showed similar to the common extraction methods in our real life to authors’ knowledge. Therefore, the objective of this study was to compa ...