Secagem e armazenamento do leite de cabra com polpa de umbu-cajá.

Abstract

Drying is an excellent conservation method for food, due to the stability and larger duty cycle that it can provide. This work aimed at creating a powder produced from the spray drying of a mixture of goat milk, umbu-cajá pulp and maltodextrin. The physiochemical characterization of the goat milk, the umbu-cajá pulp and three emulsions elaborated with the two products mentioned (1:1) and maltodextrin in the concentrations of 5, 10 and 15% was prepared. The three types of emulsions were dried in the spray dryer and the powder samples, collected separately in the drying chamber and in the cyclone, were characterized physical-chemically. Next, the storage study of the powder samples produced with goat milk, umbu-cajá pulp and maltodextrin in two concentrations (10 and 15%) was carried out for 90 days. The powder samples were produced and collected in the drying chamber and in the cyclone; and then conditioned in flexible packages, having their moisture content, ascorbic acid, titratable acidity, reducer sugars, pH, ash and color (brightness, redness and yellowness) evaluated periodically. During the storage the samples presented decreases in the moisture content, titratable acidity and redness and increases in the ascorbic acid content, reducing sugars, ash, brightness and yellowness. The combination of goat milk, umbu-cajá pulp and maltodextrin in the concentrations of 10 and 15% was considered as appropriate to obtain a nutritional powder product, by the use of a spray dryer, originating a product with appearance and flavor different from the goat milk and appropriate for storage in room temperature. The moisture adsorption isotherms were determined at 20°C of the formulation in powder produced with 15% of maltodextrin collected in the drying chamber and in the cyclone, and the Oswin, GAB and Peleg models fítted to the isotherms. The findings promoted the classification of the isotherms as type II, with sigmoid form and the Peleg model was the one that best fít to the experimental curves.