GUIMARÃES, M. K. A.; http://lattes.cnpq.br/6077837377816538; GUIMARÃES, Mary Karlla Araújo.
Abstract:
Foam layer drying of pulp and mango cv. keitt. This work aimed to obtain a powder product from mango cv. Keitt pulp through foam mat drying. At first, tests combined mango pulp and different concentrations of additives (Super Liga Neutra® e Emustab®) in order to produce stable foam, concerning density,
over-run and stability values. Based on these parameters the best formulation (Treatment 2) was selected, consisting of mango pulp, 1.0% Super Liga Neutra® and 1.0% Emustab® whipped for 20 minutes. Rheological properties of the whole pulp and of the best formulation (Treatment 2) were also evaluated at 25 ºC. It was verified that they are nonnewtonian pseudoplastic fluids, and their rheogram is best estimated through the Mizrahi- Berk model. Chemical, physical and physicochemical characteristics of the best formulation were assessed. Dehydration was carried out in an oven with forced airflow, at 50, 60 and 70 ºC, with three foam layer thicknesses (0.5, 1.0 and 1.5 cm). Drying curves were obtained from drying kinetics data; and fit to Henderson & Pabis, Henderson, and Page, Logarithmic and the Two-term Exponencial models. Physical, chemical and physicochemical characteristics of the powder products were determined, as well as the moisture adsorption isotherms at 25 ºC. For the mango powder (Treatment 2 – 60 ºC/0.5 cm) moisture adsorption isotherms at 20, 30 and 40 ºC were determined. Powder product was evaluated for stability when stored in laminated packages for 60 days under controlled conditions temperature (20, 30 and 40 ºC) and humidity (55 and 83%). The selected formulation showed density of 0.5170 g/cm3 and higher values of total solids and total soluble solids. The 0.5 cm thick foam mat at 70 ºC had the shortest drying time. The model of Page was the one that best fitted to the drying kinetic curves of the foams. Powder product presented acid pH, low water activity, high levels of total soluble solids and ascorbic acid. Isotherms were classified as Type III and the models of Peleg and GAB were those which best fitted to the experimental data. While the powder was stored, moisture content, whereas the levels of acidity, ascorbic acid, brighteness and yellowness dropped.