Obtenção de banana (Musa Sapientum L., Prata variety) desidratada enriquecida com isomaltulose

Abstract

Given the importance of dehydration processes in the extension of shelf life and food conservation, the present study aimed to obtain dried bananas, under different conditions. Different methods of isomaltulose incorporation, a low glycemic index carbohydrate with important nutritional properties, were evaluated. The physical-chemical characteristics of the dried bananas were evaluated as well as all the mathematical modeling of the drying processes. In the study, the incorporation of isomaltulose was performed using two techniques: conventional osmotic dehydration and dual-stage sugar substitution (D3S). In both techniques, it was evaluated whether the application of ultrasonic energy and the use of pre-treatments were efficient in the loss of water and gain of solids by the banana slices. The influence of isomaltulose incorporation on the drying of banana slices was also evaluated. Two drying methods were applied: heated air drying (temperatures of 60 and 70 °C) and infrared drying (temperature of 70 °C). The incorporation of isomaltulose using the D3S technique in immature Prata bananas was also carried out, evaluating their final physicochemical characteristics and dehydration kinetics, aiming at the production of a food with important nutritional properties. All the empirical equations applied in the mathematical modeling of the drying kinetics showed excellent fit (R² > 0.999), highlighting the Midilli model. In general, the use of ultrasonic energy as a pre-treatment to heated air drying and infrared drying of banana slices resulted in a drying time reduction of up to 29%, presenting higher values of effective water diffusivity, in addition to providing less shrinkage both radial and longitudinal. The immersion of samples in water prior to heated air drying proved to be an efficient treatment, reducing drying times, presenting lower energy consumption (107.57 kWh.kg-1) in addition to providing samples with better rehydration capacity. Osmotic dehydration provided the production of isomaltulose-incorporated banana slices, but was not effective in reducing drying times and kinetics parameters. However, the treatment resulted in intense colors, better physical appearance and better rehydration capacity in some cases. The use of the D3S technique proved to be efficient in the incorporation of isomaltulose in banana slices. The association of ultrasound (40 kHz) in both stages of the technique promoted greater water loss (10.0%) and greater solute incorporation (4.8%). However, samples treated by the D3S technique required longer drying times (about 370 min).