Osmotic Dehydration Process Study With Complementary Banana Peel Drying

Abstract

The present study aims to perform combined osmoconvective and convective drying processes on banana peel and evaluate the influence of these processes on their physical and physical-chemical properties. A factorial planning of 2² + 3 central points was carried out to evaluate the effect of the input variables: sucrose concentration varying between 40 and 60 °Brix and temperature between 40 and 60 °C, on the response variables: loss of water and mass and gain of solids in the banana peels. The drying kinetics was performed at 60 °C and empirical mathematical models were adjusted to the experimental data. The fresh peels, osmotically dehydrated, after drying process (in the optimized condition) and during 30 days of storage were characterized as for the parameters: pH, total titratable acidity (TTA), total soluble solids (TSS), TSS / TTA ratio, water content and total solids, ash, ascorbic acid, reducing sugars, color (L *, a * and b *) and water activity (Aw). The banana peels used in the experiments had a high water content and reasonable amounts of carbohydrates and ashes. The condition that showed the greatest reduction in water content and greatest gains in solids was using the temperature of 60 ° C and 60 ° Brix, being considered the optimized. The osmoconvective dehydration process resulted in a greater incorporation of total soluble solids and higher percentages of total solids in the shells. Page's mathematical model was the one that best fitted the experimental data; the effective diffusivity of the process was 2.2 x 10^-8 m².s^-1. And the physical and physical-chemical parameters analyzed during the storage had small changes during the period of 30 days of storage.