Advanced experimental and analytical study for the optimization of the Espresso Coffee extraction.

This PhD dissertation is the result of three years of research work, aimed at scientifically optimizing the espresso coffee extraction, particularly through a sustainable development approach to the process of brewing. For this purpose, a broad theoretical and applied research was carried out including experimental studies with espresso coffee supplementary tools, analytical methods and mathematical simulation programs. The research project has also produced four published articles, two submitted works, now under review, and some yet unpublished results. In the first study, supplementary devices are applied in the research investigation for demonstrating the influence of different variables on espresso coffee extraction with the objective of lowering the amount of coffee powder used. Lowering the amount of roast and ground coffee can lead, in the long run, to a more sustainable consumption, by reducing the amount of the raw material and, in the end, producing less amount of waste, while the same quality of the beverage are maintained through the use of different tools and the proper calibration of the corresponding variables. A follow-up study developed a new analytical method for the quantification of organic acids in espresso coffee, and its outcomes were compared with data from the sensory panel evaluation. By combining these two different assessments, it is possible to predict optimal conditions for the extraction of espresso coffee. A further follow up was the analysis of high molecular compounds in the extracted samples, implemented to research the correlation between various extractions of espresso coffee with respect to carbohydrates. In the fourth study, interdisciplinary research was implemented through a mathematical simulation program with chemical analyses on espresso coffee extraction at various parametric conditions (temperature, pressure and tamping force). This interdisciplinary approach can give a preliminary prediction of the extraction process, which further facilitates the possible applications on espresso coffee brewing. The fifth and final study was the consequent development of new cosmetic products from spent coffee. This research carried out the characterization of bioactive molecules, extracted with water and diluted solvents such as ethanol, proving the healthy effect of spent coffee on skin.