Processos para o desenvolvimento da umbuzada em pó liofilizada, composta de polpa de umbu, extrato de soja e rapadura.

Abstract

The present work has the aim to propose a new device to get the soybean extract and develop a new food product made with umbu pulp, soymilk and brown sugar, highquality protein and energetic, to supply the main nutritional needs of low-income population, especially for school lunches. The study was divided into four chapters. In Chapter 1 we evaluated the process of obtaining the soybean extract with different proportions of water: soybean (1:8, 1:10 and 1:12), the preparation of umbuzada with different concentrations of umbu pulp (30, 40 and 50%). Still, we evaluated the physico-chemical characteristic (protein, carbohydrates, lipids, pH, total acidity, ash, moisture content and calorific value), thermophysical (thermal conductivity, thermal diffusivity, density and specific heat), the sensory properties (color aroma and flavor) of soymilk, umbu’s pulp, umbuzada’s formulations. In Chapter 2 we studied the Rheological behavior (10, 20, 30 and 40 °C) of the soymilk of umbu’s pulp and umbuzada’s formulations and it was evaluated from the model Ostwald-Waelle and Casson which represented the rheological behavior. In Chapter 3 we studied the freezing kinetics and the effect of freezing conditions on the physico-chemical characteristic, sensory and microbiological umbuzada’s formulations. Moreover, the formulations were evaluated in the umbuzada storage conditions at temperatures of (-20 °C, the -170 °C to -50 °C in nitrogen steam liquid and -196 °C to -50 °C by immersion in liquid nitrogen). In Chapter 4, we studied the kinetics of drying by lyophilization umbuzada’s formulations frozen in three conditions (-20 °C and -50 °C in steam and immersion in liquid nitrogen), they were evaluated from the models Cavalcanti Mata, Page and Midilli which represents the behavior of the drying curves with precision, and quantified the effect of freezing temperatures and the percentage of umbu’s pulp in physico-chemical and sensory umbuzada lyophilized. Based on the results obtained the soy extract in proportion soybean: water 1:8 showed better physico-chemical and sensory. The thermal conductivity and thermal diffusivity decreases and density increases with concentration increasing of umbu’s pulp. Models Ostwalt-of-Waelle and Casson were, in general, those which better represent the behavior rheology of the soy extract, the umbu’s formulations and temperatures studied. Freezing to -50 °C by immersion in liquid nitrogen had the lowest freezing time. The average effective diffusivity increased according to the order of presented freezing method: -20 °C to 50 °C in nitrogen steam and 50 °C by immersion in liquid nitrogen. The formulation with 50% umbu’s pulp show the highest rate of drying by lyophilization and Cavalcanti Mata model was the one that best represented the behavior of drying curves by lyophilization.