Effects of refrigeration and oxygen on the coffee brew composition

The aim of this work was to monitor the changes both in the composition and in some sensory parameters of Colombian Arabica coffee brews stored at room and refrigeration temperatures, with and without oxygen. Some nonvolatile compounds related to the taste of coffee brews were determined, in an attempt to study possible relationships between chemical and sensory changes. Storage time hardly affects the amounts of chlorogenic, caffeic and ferulic acids, reported to have some beneficial health effects, mainly due to their antioxidant activities. In contrast, pH decreases in all the coffee brews along the time, mainly in that stored at 25 degrees C with oxygen. The appearance of sourness and other non typical coffee tastes (rancid taste, aftertaste) and an increase in astringency leads to establish a shelf-life of 10 days for coffee brews stored at 25 degrees C with oxygen, 15 days for coffee brews stored at 4 degrees C with oxygen and at 25 degrees C without oxygen, and 20 days for coffee brews stored at 4 degrees C without oxygen. The behaviour of 5-caffeoylquinic acid, caffeic acid and 4-vinylguaiacol throughout time was different from other studies conducted at higher temperatures to accelerate the staling, what reveals that stability studies of coffee brews should be made in real time and temperature.