Antioxidant capacity of the coffee brews prepared with different coffeemakers (filter, plunger, mocha and espresso) was measured by colorimetric (Total Phenolic compounds and ABTS) and Electro Spin Resonance (ESR) spectroscopy techniques (Fremy's salt and TEMPO). Mocha coffeemaker had the highest yield in coffee antioxidant extraction per g of ground roasted coffee, but espresso coffee was the richest in terms of antioxidant intake (per mL of coffee brew) followed by mocha, plunger and filter. Both Folin-Ciocalteau (Total Phenolic compounds) and ABTS assays reacted with standard solutions of chlorogenic acids (CGA) and melanoidins (MO-Ala and MO-Gly). However, Fremy's salt was mainly scavenged by chlorogenic acids, whereas the stabilized radical TEMPO was effectively scavenged by melanoidins, but not by chlorogenic acids. Thus, electron spin resonance (ESR) spectroscopy allows distinguishing between phenolic and nonphenolic antioxidants.Moreover, the addition of pH-regulator agents to coffee, such as sodium carbonate (75ppm) and bicarbonate (75ppm), to extend its shelf-life, slightly increases the pH, modifying the antioxidant capacity in those coffee brews with the highest capacity (mocha and espresso).

which show a good correlation with some sensory attributes, not only for aroma but also overall sensory quality. Consequently, they could be considered useful to monitor both the "age" and the sensory quality of stored coffee brews.

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 25ºC 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 25ºC with oxygen, 15 days for coffee brews stored at 4ºC with oxygen and at 25ºC without oxygen, and 20 days for coffee brews stored at 4ºC 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.

The aim of this work was to obtain a black coffee brew to be consumed hot by extension of its shelf-life, by addition of additives. Four pH-regulator agents (sodium and potassium carbonates and bicarbonates), one pH-regulator and antioxidant (sodium citrate), three antioxidants (sodium ascorbate, ethylenediaminetetracetic acid (EDTA), and sodium sulfite), and lactoserum were tested by sensory analysis. Sodium carbonate and bicarbonate were selected for a study of the physico-chemical (soluble and volatile compounds related to the sensory properties) and sensorial quality of coffee brew stored during 90 days at 4ºC.Although both additives extended the shelf-life of the coffee brew up to 60 days, sodium carbonate was the chosen additive because it was the most useful in limiting the pH decrease and perception of sourness, which are some of the main factors involved in the rejection of stored coffee brews, and maintain better the aroma and taste/flavor. Moreover, the application of multivariate analysis facilitated, firstly the description of the global changes of the coffee brews with or without additives throughout the storage using the Principal Component Analysis (PCA), and secondly, to obtain a simple equation only with pH and caffeic acid parameters to discriminate the three types of coffee brews and simplify the analytical process, by means of the Stepwise Discriminant Analysis (SDA).

In this work, the influence of an Ultra High Temperature (UHT) treatment on chemical and sensory composition of Arabica coffee brews for a longer shelf-life has been studied. A temperature of 120 ºC for 2 s allows to obtain a microbiologically safe coffee brew, good valued from the sensory point of view. The behavior of the UHT vs non UHT treated coffee brew was followed throughout 120 days of storage at 4 ºC. The UHT treatment keeps longer the typical acidity of the brews, delaying and softening the pH decrease and the development of sourness, which is one of the main causes for the rejection of stored coffee brews. The UHT treatment hardly affects the concentrations of caffeine and trigonelline, and of some phenolic compounds such as 5-caffeoylquinic (5-CQA), caffeic or ferulic acids. Sixteen key odorants and staling volatiles were analyzed by HS-GC-MS and lower changes were observed in the UHT treated coffee brew throughout storage. Higher DPPH · scavenging activity was observed in the UHT treated coffee brew from days 60 to 120. In conclusion, the application of an UHT treatment is proposed to extend the shelf-life (up to 60 days) of stored coffee brews.