Secagem em camada de espuma, caracterização físico-química e armazenamento da polpa mista de acerola com melancia em pó.

Abstract

The mixture of fruit pulps has the purpose of improving the nutritional and sensorial characteristics of the components consumed in isolation and the powder products has as main function to increase the useful life of the product in natura. The objective of this work was to dry foam maturation of mixed acerola pulp with watermelon (1: 1), with the addition of additives with different concentrations (Neutral®, Emustab® and Pectin). Initially tests were carried out with different formulations (F1, F2, F3 and F4), in which Formulation F4 (2% Emustab, 2% Neutral Alloy and 1% Pectin) was defined based on the parameters of volumetric expansion, Density and stability to be the formulation to be dried in a foam layer at temperatures of 60, 70 and 80øC and with thicknesses of the foam layer of 0.5, 1.0 and 1.5 cm. The physical, chemical and physicochemical properties of the whole and mixed pulp of acerola and watermelon and of the powders produced were analyzed. The best powder was selected based on the values of yield and acidity, and this was packed in laminated containers and stored for 40 days at temperatures of 30 and 40 ° C and approximate average relative humidity of 83%, being evaluated each 8 days of chemical, physical and physicochemical characteristics (water content, pH, titratable total acidity, water activity, color, solubility and anthocyanins). The mixed pulp of acerola with watermelon (1: 1) showed high water content, ascorbic acid, phenolic compounds, and is an acidic food; From the drying kinetics curves it was found that the increase of the drying temperature (60, 70 and 80 ° C) and the reduction of the thickness of the foam layer (0.5, 1.0 and 1.5 cm) promoted a Greater heat transfer and mass reducing the time for the formulation to reach equilibrium water content; And all adjusted models (Page, Two Terms, Henderson and Pabis, Lewis and Henderson and Modified Pabis) can be used with good accuracy in estimating the drying curves of Formulation F4, especially the Page model. Formulation F4 powders presented high ascorbic acid content, low water activity and high acidity; All adjusted models (Peleg, Halsey, GAB and Oswin) can be used to estimate the water adsorption isotherms, at the temperatures of 25, 30 and 35 ° C, of the selected powder (Formulation F4 dried at 80 ° C with And the isotherms were classified as Type II (sigmoidal form); During the storage, at the temperatures of 30 and 40 ºC, of the selected powder it was verified that with the storage time there was increase of the water content, water activity and pH and reduction of solubility, total anthocyanins, luminosity and intensity of yellow.