The volatile compounds pattern of the coffee beverages is affected by various factors including variety and origin of green coffee beans (C. arabica and C. canephora), as well as processing parameters being roasting and the extraction modality the most important ones. Roasting, heat treatment carried out at 200-240 °C, induces major physicochemical and structural changes in the coffee bean and determine the peculiar flavor properties of the roasted product. The aroma of the roasted coffee is extremely complex being the consequence of a series of reactions (e.g. Maillard reaction, sugar caramelization and many others). Brewing methods and conditions determine a different extraction of volatile and non-volatile compounds with effect on the aroma pattern. Furthermore, in many countries sugars are added to coffee brews to improve sensory acceptability by reducing bitterness and astringency. In this study, the effect of sucrose, lactose, glucose, maltodextrin and their concentration on the aroma pattern and the liquid-vapour partition of selected key volatile compounds has been investigated by GC-MS in both espresso coffee and ready-to-drink (RTD) canned coffee obtained by using the same Arabica roasted coffee beans blend. An e-nose system made of an array of porphyrin sensors was also tested. Saccharides affected the release of the volatiles and thus the coffee aroma profile with differences due to the type of added sugar and coffee brew type; non-volatile components in the coffee brews could be implied in the differences of k values of the volatile compounds in respect to that observed in water. The effects of the sugar type on the release/retention of the key coffee aroma compounds was partly explained in terms of “salting out” especially for the more polar volatile compounds and in the sucrose-added model systems. However, saccharides could induce changes of other chemical and physico-chemical properties of the water and brews as well as the occurrence of interactions between volatile compounds and non-volatile components that may be implied in the reduction of the vapour partition of the coffee aroma compounds.

Effect of sugars on vapour partition of volatile compounds of coffee beverages

255th National Meeting (2018)

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