Produção de farinhas de sementes germinadas de abóbara.

Abstract

Vulture seeds are a by-product of fruit processing and are discarded, in most cases, without further applications. Germination is a simple method that has the ability to reduce the concentration of antinutritional compounds in the seeds, improve their nutritional quality and the technological properties of the flours produced. Given the above, the objective was to produce flour from sprouted seeds of pumpkin. The germination of the thread seeds was carried out using germested paper as a substrate, in a germination oven at 25ºC for 48h. The seeds of vulture in natura and germinated were characterized in terms of chemical and physical-chemical parameters. The germinated seeds were subjected to convective drying, at temperatures of 50, 60 and 70ºC and air velocities of 0.5; 1.0 and 1.3 m s-1, determining drying kinetics. The experimental data were adjusted to different mathematical models frequently used to represent the drying kinetics of agricultural products. The effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain the activation energy. After drying, the seeds were ground and the flours obtained were evaluated for physical, chemical and physicochemical properties. Flour water isotherms were determined at a temperature of 25ºC and the mathematical models of Oswin, GAB and Peleg were adjusted to the experimental data. It was found that the germination of pumpkin seeds caused an increase in its water, protein, lipid and reducing sugar content, but a reduction in the content of carbohydrates, ash, phenolic compounds and tannins. The Diffusion Approximation, Two Terms, Midilli et al., Page and Thompson models showed good adjustments to experimental drying data. The increase in the drying temperature reduced the drying time of the seeds, increased the rate of water removal and the effective diffusion coefficients. The activation energy for drying germinated pumpkin seeds ranged from 2.73 to 8.11 kJ mol-1; as the drying temperature increased, there was an increase in total titratable acidity, lipids, red intensity (+ a *), yellow intensity (+ b *), apparent and compacted density, but reduced luminosity (L * ), solubility and wettability; the Peleg model presented the best adjustments to the experimental data of the isotherms presenting the highest determination coefficients (R²) and the lowest mean percentage deviations (P).