EVALUATION OF A STAGE IN THE DEVELOPMENT OF A METHODOLOGY: HOT AND COLD EXTRACTION WITH ARABICA COFFEE FROM THE CERRADO MINEIRO FOR THE PRODUCTION OF SPECIALTY SOLUBLE COFFEE

There is a market demand for a drink that offers the practicality of instant coffee combined with the characteristics of a speciality coffee. With this in mind, the aim of this study was to develop a methodology for obtaining freeze-dried speciality soluble coffee from Coffea arabica beans from the Cerrado Mineiro region, assessing the yield of the process and the physical and chemical characteristics of the final product. To do this, two extraction methods were compared: hot and cold. The coffee beans used were previously roasted to a medium roast profile by the Federation of Coffee Growers of the Cerrado, this profile being considered suitable for the extraction of aromatic compounds. The samples were extracted by infusion in water at controlled temperatures of 100°C for 30 minutes (hot) and 25°C for 30 minutes (cold). The extract was then filtered and concentrated in an IKA RV 10 Digital rotaevaporator until it reached 28 °Brix. The extracts were then frozen in an ultrafreezer at -86°C for 12 hours. The concentrated coffee was then freeze-dried for 24 hours to obtain the soluble powder. The entire process was carried out with strict control of time, temperature and the ratio between coffee (62.5g) and water (250g), using suitable equipment to simulate the industrial process on a small scale. The main determinants considered when choosing the methodology were the yield and the colour and water activity (Aw) characteristics of the powders obtained. Colour analysis was carried out using a DeltaVista® colorimeter, obtaining the parameters L*, a* and b*, and Aw was determined using AquaLab equipment. Hot extraction showed the best overall performance, resulting in 8 g of soluble powder from 62.5 g of roasted coffee, as well as lower water activity (Aw = 0.351), favouring product stability, and darker colour (L* 25.28; a* 2.32; b* 1.00). On the other hand, cold extraction resulted in a lower yield of 3g, with a slightly higher Aw (0.361) and a lighter coloured powder (L* 28.42; a* 3.55; b* 3.97), tending towards reddish and yellowish tones. Hot extraction therefore stood out as the most promising method, not only in terms of yield, but also because it offers better stability and a more characteristic visual profile of soluble coffees.