Estudo da secagem da polpa do abacate (Persea americana)

Abstract

The drying process can be carried out by different methods, but the choice directly influences the quality of the final product, which can obviously be affected by operational conditions. This work aims to study the drying of the avocado pulp, through process optimization and experimental analysis. To achieve the proposed objective, this study was divided into two stages. Initially, the equipment to be used for drying the fruit pulp was defined. For this, the process synthesis techniques were applied, such as making the branch-and-bound trees, heuristic rules and determination the base flowchart, using the fuzzy logic method. From the application of the process synthesis, the lyophilization equipment proved to be promising for the drying process of the fruit pulp. After, considering that the knowledge of the drying rate is essential in the choice of suitable conditions for the lyophilization process, and the experimental data obtained to determine the drying kinetics, in the simplest lyophilizer, are measured in a discontinuous way, through destructive analysis, a simplest and low-cost setup for a laboratory-scale lyophilizer was developed, with an automated data acquisition system. The setup made it possible to obtain the drying kinetics curves, the temperature of the material as a function of time and the pressure difference, in addition to controlling different temperatures of the heating tray. The study was evaluated for the drying of the avocado pulp with heating temperature of 30, 40, 50 ° C and also without the supplying controlled of heat. The data acquisition system implemented proved to be satisfactory for the conditions evaluated. As expected, the load cell was influenced by the operating conditions, but the data was reproducible, so it was possible to minimize errors in the measurement of mass. The controlled supply of heat during lyophilization accelerated the process and, consequently, had a direct influence on the drying rate. In addition to the tests related to lyophilization of the avocado pulp, the influence of drying on the morphology, thermal decomposition, rehydration capacity, color, phenolic compounds and antioxidant activity of the fruit pulp was verified. It was observed that the heating temperature had an influence on the evaluated parameters, with temperatures of 40 and 50 ° C being the most appropriate for the process of dehydration of the fruit pulp. This study proved to be important for the analysis of the steps that occur during the lyophilization process.