Secagem por aspersão da polpa de manga cv. Keitt.

Abstract

This work was developed with the goal of dehydrated mango cv. Keitt pulp type through the spray drying process, analyzed, through a factorial experimental design, the powdered product obtained, followed by the study of storage under controlled conditions and the kinetics of degradation of ascorbic acid powder product selected in the planning. Mango cv. Keitt fruits were evaluated for parameters like size, dimensions and pulp yield. Three formulations were prepared with pulp full sleeve containing three different concentrations of the additive maltodextrin (30, 35 and 40%). Mango pulp and formulations were characterized according to chemical, physical and physicochemical parameters. The formulations were dried in spray dryer at temperatures of 160, 175 and 190 ºC. The powders obtained at the end of the drying variables were analyzed for their response to moisture content, yield, water activity, ascorbic acid, hygroscopicity, brightness, redness and yellowness. Other chemical and physical analyzes helped to select the powder to be selected for the study of the controlled storage in two humidity (55 to 83%) and three temperatures (20, 30 and 40 °C) and to study the kinetic of degradation of ascorbic acid at temperatures of 20, 30 and 40 °C. The moisture adsorption isotherms were determined at 20 ºC, the sample selected by factorial design dust and fitted GAB, Oswin and Peleg models. It was found that the Keitt mango fruit is considered large with excellent yield pulp. The full Keitt mango pulp is acidic and has a high moisture content, and has a predominance of yellow color. Comparing the formulations with the whole pulp there was a decrease of moisture content, ascorbic acid, total acidity, ash, non-reducing sugars, brightness, redness and yellowness; and increased pH, total soluble solids, total solids, reducing sugars, total sugars and density. It was found that the formulations with increasing concentration of maltodextrin lowering the pH, moisture content, total solids, redness and yellowness occurred; and increased total soluble solids, ascorbic acid, ash, specific mass and luminosity. Through factorial experimental design it was found that the best powder was found from Experiment n° 4 (40% maltodextrin; drying air temperature of 190 °C) collected in the drying chamber. The model that best fit the experimental data of the moisture adsorption isotherm of the selected powder was the GAB, and was classified as type III. It was found during storage of the powder (Experiment n° 4) collected in the drying chamber, the laminated flexible packaging were not effective enough against variation of parameters evaluated at relative humidities of 55 and 83%, although they have avoided variation sharply with increasing temperature. It was also found an increase in moisture content, water activity and acidity during storage time; and a tendency to decrease or reduction in the brightness yellowness, redness, ascorbic acid, pH and solubility. In the kinetic of degradation of ascorbic acid powder collected in the chamber (Experiment n° 4) it was found that with increasing temperature was increased degradation of ascorbic acid.