Secagem e armazenamento da polpa de pitanga.

Abstract

The dehydration of Surinam cherry pulp (Eugenia uniflora L.) was done in spray dryer and the resulting powder was stored for 120 days. The pulps used in the dehydration were produced through the removal of the pulp from Surinam cherries. Samples of integral and formulated pulps (Surinam cherry pulp + 15% maltodextrin + 30% distilled water) were elaborated. These samples were submitted to physiochemical analyses to determine the content of total solids, moisture, total soluble solids (ºBrix), pH, titratable total acidity, ascorbic acid, ashes, reducer sugar, proteins, alcoholic extract and color analyses, the brightness (L*), redness (+a*) and yellowness (+b*). The rheological behavior of the pulps was also evaluated at the temperatures of 10, 20, 30, 40 and 50ºC. The rheograms were fitted with Ostwald-de-Waele, Herschel-Bulkley, Casson and Mizrahi-Berk models. In the drying, accomplished from the formulated pulp, two sample types were collected, according to the accessory of the dryer from where they were collected: Type A (drying chamber); and Type B (cyclone). At the powdered samples, the density, time of drainage, moisture, ascorbic acid, titratable acidity, reducer sugar, proteins, alcoholic extract and moisture adsorption isotherms were determined. The isotherms were determined through the static gravimetric method at the temperatures of 10, 20, 30 and 40ºC. They were fitted to the experimental data through GAB, Peleg, Halsey modified, Smith, Day & Nelson and Sigma-Copace’s models. The powdered pulps were put in polyethylene and laminated packings, stored in room temperature. The moisture content, ascorbic acid, titratable acidity, proteins, alcoholic extract and, in the beginning and at the end of the storage, the evaluation microbiological were evaluated every 20 days. The integral pulp presented larger moisture, pH, titratable total acidity, ascorbic acid, ashes, reducer sugar, proteins, alcoholic extract, brightness, redness and yellowness values compared to the formulated pulp. The formulated pulp presented larger values of total solids and soluble solids. The powdered samples (Types A and B) presented different times of drainage, density, moisture, reducer sugar and alcoholic extract, without demonstrating statistical difference for the ascorbic acid content, acidity and proteins. The integral and formulated pulps presented no-Newtonian and pseudoplastic behavior, with Herschel-Bulkley and MizrahiBerk’s models presenting the best adjustments. Peleg’s model presented the best adjustment to the moisture adsorption isotherms at the evaluated temperatures to the powders types A and B. It was verified, during the storage, that it had gain of moisture and reduction of acidity, of the alcoholic extract and of the ascorbic acid in the two types of powdered samples (Type A and B) conditioned in the two packings (polyethylene and laminated). Just in the Type A sample, put in laminated packing, the proteins content stayed unaffected. There were verified decreases in the other cases. The microbiological evaluation revealed that the samples were in acceptable levels for consumption.