Physico-chemical, nutritional and microbiological evaluation in banana (Cavendish Valery) dried by Freeze-drying, Refractance Window and Forced convection

In this study, the effect of the temperatures used in the drying processes on the physicochemical (texture), nutritional (fiber, vitamins A and C, antioxidant capacity) and microbiological properties of banana slices using drying processes such as freeze drying, Refractance window (VR) and forced convection was evaluated. Freeze drying was used at temperatures of -40 C and a vacuum level of 130 microns of hg, in the Refractance Window the temperature of the process was 90 degrees C and in the convective drying temperatures were between 75 - 80 degrees C. It was found that in the drying methods by freeze drying, VR and forced convection presented significant difference on the response variables (fiber, vitamins A and C) and in the other response variables (antioxidant capacity and strength of fracture) did not present significant differences. The values of the slices dried by the three methods showed the following results: Higher fiber content (L) 11,507 g / 100 g, the highest content of vitamins A and C were found (VR) 9,147 IU / 100 g and 7,727 mg / 100 g, in the antioxidant capacity the highest value found was (VR) 2091,00 moles eq.Trolox / g, the highest value of fracture strength was (L) 63,93 +/- 9,60 N, and the value of the microbiological analysis are (L) fungi 50 and yeast 140 CFU / g-mL, (VR) fungi <10 and yeast <10 CFU / g-mL and convective fungi <10 and yeast <10 CFU / g-mL, the results obtained by the ANOVA analysis of variance obtained sample that the VR process is an efficient method to conserve said nutritional properties of the dehydrated banana snack.