Effect of processing on bioaccessibility and bioavailability of bioactive compounds in coffee beans

Abstract

Coffee is one of the most prevalent and functional beverages around world owing to its rich content of bioactive compounds. Phenolic compounds and alkaloids are two primary groups of bioactive compounds in coffee beans, which have been proven healthy benefits in regular and suitable daily consumption. They have been recognized as protective factors, especially phenolic compounds, to perform high antioxidant capacities and potential to relieve the occurrence of chronic diseases and partial cancer. The content and composition of bioactive and anti-nutritional compounds in coffee beans can be mainly influenced by variety, processing and storage conditions. The cultivar of Arabica coffee beans (C. arabica) exhibits lower content of phenolic compounds but similar anti-nutritional substances with the comparison to Robusta (C. canephora). Comparing to green coffee beans, reasonable roasting contributes to the improvement of phenolic content and its total antioxidant activity because of the liberation of bound phenolic compounds and the generation of novel compounds with antioxidant activity. Over intensive roasting will not only decrease the number of bioactive compounds within the coffee beans but also stimulate the generation of endogenous anti-nutritional compounds, which consequently reduce the coffee nutritional value. The fluctuations of moisture content during storage would be the primary reason of the changes in the content of bioactive compounds. Phenolic compounds in coffee beans perform outstanding bioaccessibility but relatively lower absorption efficiency because of the combination with other molecules. Suitable roasting would improve the bioavailability of bioactive compounds. The interaction between phenolic compounds and proteins would also influence the bioavailability and bioactivity of bioactive compounds and final nutritional value after consumption.