Secagem de café com polpa em secador solar de bandeja

Abstract

The use of non-renewable, dispendious energies in drying operations is a setback for the arrival of a lower-priced beverage coffee. Solar energy is the best alternative to replace that issue on this operation for being low-cost and plentiful especially in central Brazil region Triangulo Mineiro. Coffea arabica is the most popular coffee drink in the world, Brazil being the first producer of the fruit. The drying operation of the coffee fruit in the country is made in concrete yards, which are vulnerable to dust and other pathological agents brought by wind or small animals, besides being vulnerable to rain. The solar drying using tray dryers is an alternative that includes both solar energy plenty and a better protection to precipitations and natural weather. This work aimed to evaluate the use of a solar tray dryer as an alternative to dehydrate Coffea arabica fruits, varying the volumetric air flow rate and the fruit’s mass load. The temperature achieved by the dryer ranged from 49°C to 58°C and managed to dry the fruit from 34.71% down to a mean value of 15.5% enough to storage in six hours. Degradation of phenolic and flavonoid compounds were observed, although in low amounts, witnessing an important effect of the drying air temperature, that modifies inhibitory enzymes and the bioactive compounds themselves by thermal stress. Hence, to maintain bioactive compounds close to natural stage, high temperatures are desired.