Secagem do resíduo industrial do despolpamento de acerola (Malphigia spp.) em leito de jorro

Abstract

Acerola is a typical fruit of the Americas and with a strong incidence in Brazil, a country that stands out in the production, consumption and export of the fruit. Its agro-industrial chain involves, to a large extent, the pulping of the fruits, which generate a residue composed mainly of seeds, as well as peels and bagasse. This residue has functional appeal due to the presence of bioactive compounds. Enabling the use of this residue is an alternative for the development of a more efficient and sustainable process. However, this type of waste contains high humidity, which contributes to its rapid deterioration and, therefore, it is essential that it undergoes a drying process, thus allowing it to prolong its useful life, for later use, for example, in flour production. One of the alternatives is spouted bed drying, equipment that stands out for its high rates of heat and mass transfer, which contributes to an efficient reduction of humidity. Given the above, the objective of the present work was to study the drying of acerola pulping residue in spouted beds, analyzing the influence of the process on the functional quality of the residue. The physical characterization of the residue and the porous medium was carried out by measuring the following properties: average diameter, sphericity, apparent density and bulk and compacted bulk, bulk porosity, weight of a thousand seeds, moisture and angle of repose. In addition, vitamin C and DPPH analyzes were performed. In addition, drying experiments were carried out in a conventional spouted bed, varying the parameters: % of residue in natura, speed and temperature of the drying air. The porous medium showed high values of bulk density (567.69 kg/m³) and angle of repose (56°) and low porosity (0.6), indicating difficulty in fluidizing the material. For this reason, mixtures with 20% and 30% of in natura acerola residue were used in the drying tests. From the characteristic curve of the bed, the fluid dynamic parameters were identified for the two mixture fractions. It was possible to identify that higher values of temperature and air velocity and lower percentages of wet material in the mixture, provide a greater reduction in waste moisture, and the best drying condition was observed for the experiment with 20% of wet material, speed of drying air of 36 m/s and temperature of 60°C. In general, the spouted bed was effective in removing moisture and preserving the bioactive compounds from the acerola residue, operating in short periods with low air temperatures.