CINÉTICA DE SECAGEM, CARACTERIZAÇÃO E ARMAZENAMENTO DE FARINHA DE BATATA-DOCE BIOFORTIFICADA

Abstract

Sweet potato (Ipomoea potatoes (L.) Lam.) is a vegetable that has great nutritional potential, the orange pulp has significant provitamin A carotenoids contents, which can be used to flour production. However, studies about processing and storage conditions are needed to minimize nutrient loss. The objective of this research was to study the drying kinetics of biofortified sweet potato pulp at temperatures of 45, 55, 65 and 75°C, testing the AIC and BIC criteria, to determine the effective diffusion coefficient during drying, to evaluate the proximal composition, pH, acidity, phenolic compounds, carotenoids, β-carotene, antioxidant capacity by ABTS and DPPH, fibers, color, scanning electron microscopy, high-field nuclear magnetic resonance, infrared absorption spectrometry, as well as to determine absorption rates in water, oil and milk of biofortified sweet potato flours at different drying temperatures 45, 55, 65 and 75°C. Also store dry flour at 55 ºC for one year at room temperature, and evaluate the proximal composition, pH, acidity, phenolic compounds, carotenoids, b-carotene, antioxidant capacity by ABTS and DPPH and color. The drying kinetics of the biofortified sweet potato pulp can be described by the Wang and Singh model because it exhibits the best fit under most conditions. The effective diffusion coefficient increased with the increase of drying air temperature and the activation energy for the liquid diffusion was 29.18 kJ mol-1. Flours obtained from sliced roots dried at 45, 55, 65 and 75ºC were stable in their proximal and morphological composition. The temperature of 45°C was the most suitable for the biofortified sweet potato flours production, since it had higher content of bioactive compounds, being an excellent carotenoids source. The flour has favorable technological characteristics for covering breaded or for crunchy products. During storage, the proximal composition of biofortified sweet potato flour remained stable, but there was a significant reduction in color, antioxidant capacity, phenolic compounds, carotenoids and b-carotene during storage.