The effect of storage conditions on physical, chemical and sensory properties of Turkish coffee

In addition to the brewing and presentation technique of Turkish coffee, the most important feature that distinguishes it from other coffees is that the grinding degree of the bean is determined within the framework of standards. Particle size of powdered foods such as coffee directly affects the rates of chemical reactions that occur during storage. Furthermore, the moisture absorption rate of the product changes depending on the particle size. As a matter of fact, within the scope of this thesis, coffees with different grinding degrees, including very fine (47.13-54.64 µm), fine (89.25-119.88 µm) and fine medium (248.77-312.23 µm), representing the dimensions of Turkish coffee, were stored at 5, 25 and 45°C for 28 days. The changes in some quality characteristics (moisture content, color values, chlorogenic acid content, caffeine content, fatty acid composition, aroma composition and sensory properties) were investigated during storege period (0th, 14th 28th). Chlorogenic acid and caffeine, which are the components responsible for the bioactive properties of coffee, varied between 1.05-1.38 g/100g DM and 1.49-1.80 g/100g DM, respectively, depending on the storage conditions. Linoleic acid (41.86-42.89%) and palmitic acid (33.23-36.36%) were determined as the main fatty acids in coffee samples, as well as oleic acid (10.59-11.47%), stearic acid (7.38-8.48%) and trace amounts of myristic acid, margiric acid, elaidic acid, cis-11 eicosenoic acid, arachidic acid and behenic acids were also detected. While vinyl furan, 2,5-dimethyl-4-hydroxy-3(2H)-furanone; 2-methoxy-phenol (Guaiacol); Components such as 3,4-dimethyl-1H-pyrrole-2-carboxaldehyde was detected in the aroma composition of coffee at the beginning of storage; these compunds were relased from the product depending on the storage period. It has been observed that as the storage time increases, many of the aroma components of the coffee decrease and the coffee aroma is best preserved in the samples stored at 5°C. As a result of the sensory analysis, the sample in which the coffee aroma is felt the most and the most preferred sample in terms of general taste was the control group made from freshly ground coffee that was not subjected to storage, and the sensory evaluation results closest to this sample were obtained in the samples stored at 5 °C.