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Influência de pré-tratamentos com emulsões a base de lecitina e óleo de soja na cinética de secagem da uva rubi

2005; Linguagem: Inglês

2639-6459

Maria Angélica Marques Pedro,

Textile materials and evaluations

Summary The objective of this work was to determine the most appropriate chemical pretreatment to be used in the drying process of grapes of the Rubi variety for raisin production. Drying curves for convective moisture removal from the Rubi grape with air at 60 °C and 0.9 m/s were built for samples pre-treated with different concentrations of lecithin, soy oil and potassium carbonate for different dipping times, according to a factorial design. The experimental data of the drying curves were adjusted to the model of Page. The drying kinetics was studied by statistical analysis of chemical pretreatment effects - dipping time and concentration of lecithin, potassium carbonate and soy oil - on the K parameter of Pages model. Immersion time and its interactions with the concentrations of the components under study were not significant at the 95% level. When all the components were used at the maximum and minimum concentrations tested, for 3 min of immersion time, K also increased and a direct relationship with drying rate and reduction of the drying time was observed. The pretreatment tested -solution of lecithin, soy oil and potassium carbonate- did not influence the behavior of the sorption isotherms. The isotherms were constructed at temperatures of 33, 40, 49, 55, 61 and 68 °C. The GAB model fitted the data of the isotherms of the Rubi grape with R 2 > 0.99.