Chapter 10 - Effects of Preparation Techniques on the Antioxidant Capacity of Coffee Brews

Abstract

The technique of coffee brew preparation markedly affects the sensory properties and bioactive composition, especially antioxidant potential of final coffee brew. This paper provides an insight into the effects of different brewing techniques on the antioxidant capacity and bioactive compounds of differently prepared coffee brews. By comparing the results of different studies, no general conclusion can be deduced regarding the effect of brewing technique on the antioxidant capacity and total phenol content, since the evaluated parameters are dependent on numerous factors, such as coffee species, origin, roasting degree, grind size, brewing ratio (coffee sample to water), brewing time, etc. However, it can be observed that instant (soluble) and espresso brews, in several studies, exhibit higher antioxidant potential and phenolic content when compared to other brews, while filter coffee provides lower contents. This is also the case for caffeine and diterpene cafestol, which can be found in higher amounts in boiled or instant coffee brews and in lower amounts in filtered coffee brews. The majority of studies agree that decaffeination and milk addition to coffee brews decrease their antioxidant capacity.