Obtenção de beterraba em pó mediante secagem por atomização.

Abstract

Obtaining beet powder by spray drying. The beet is a vegetable with high betalains content, a natural pigment that has antioxidant properties and bring health benefits, however, have a short shelf life. For this reason this work was developed with the goal of producing a product in powder form from beet pulp, through the method of drying by atomization using 5% maltodextrin and evaluate its stability during a storage period. This was a 2² experimental design with 3 center points, comprising two input variables: Drying air temperatures (70, 80 and 90 ° C) and flowrate of the suspension (4, 5 and 6 mL / min) concerning the response variables : phenolics and water activity. From the result of the design used the central point (drying air temperature of 80 ° C and suspension flow rate of 5m L / min) to the intermediate temperature and suspension flow rate to perform the study of the drying process and characterization of beet powder during storage. We conducted storage of the selected powder at room temperature for 180 days to evaluate the chemical, physical and physico-chemical characteristics and for 90 days to analyze the bioactive compounds also were determined isotherms for water adsorption at temperatures of 20, 30 and 40 ° C models GAB, Oswin and Peleg were adjusted to the experimental data. The betalains were the pigments that predominated in beet pulp and phenolic compounds were the bioactive compounds that showed higher levels. The experimental design for the study was not statistically significant responses or predictive. Powder beet showed high solubility and porosity and has shown to be non-hygroscopic. An increase in water content of reducing sugars, the redness a *, and the color parameter b * and reduction of, ascorbic acid and the brightness and stability trend acidity, total solids, total sugar and water activity during the 180 days of storage and a decrease for all bioactive compounds analyzed during the 90 days of storage. The Peleg model was the best adjusted the experimental data showing coefficient of determination (R ²> 0.99) and average percentage deviations (P <7%). The isotherms were exponential behavior and were classified as type III.