Impact of milk addition on sensory properties and the antioxidant potential of coffee

Autoren:Majchrzak, Dorota; Horvath, Marion; Woda, Marlene
Abstrakt:Coffee is one of the beverages consumed throughout the world for its unique sensory properties and physiological effects. Several studies indicated that a high content of polyphenols in coffee plays an important role in its strong antioxidant action. However, coffee beverages are often consumed with milk and polyphenols’ ability to interact with dietary protein results in partial masking of their antioxidant power. The aim of this study was to evaluate to what extent milk addition modify antioxidant potential of coffee and consequently their sensory attributes. The coffee samples were investigated without milk, as well as with 10 ml, 20 ml and 30 ml full cream milk (3,6% fat)/100 ml coffee. The Total Antioxidant Capacity (TAC) of two coffee species, Santos/Arabica and Uganda/Robusta, prepared as filter brews was measured photometrically. The sensory investigation was done by applying Quantitative Descriptive Analysis (QDA). The descriptive panel (n=10) evaluated over 2 sessions the intensity of 21 sensory descriptors of coffee samples served in randomized order. The analytical investigation showed that a significant (p<0.05) decrease in the total antioxidant capacity of coffee due to the milk addition could be found in both coffee species by the addition of 30 ml of milk/100 ml beverages. At this amount of milk the remarkable differences in typical sensory descriptors between Arabica (overall, roasty, fruity, dark chocolate flavour) and Robusta (burnt, woody. Earthy, musty, hay-like flavour, bitter taste and aftertaste, astringency) significantly (p<0.05) diminished and the intensity of the most attributes did not differ between the both coffee species. This observation suggests that milk addition could modify the antioxidant power of coffee and coffee’s flavour profile in such a way that Arabica and Robusta are not distinguishable from each other.