OSMOTIC DEHYDRATION OF BANANAS (MUSA SAPIENTUM, SHUM.) IN TERNARY AQUEOUS SOLUTIONS OF SUCROSE AND SODIUM CHLORIDE

Abstract

ABSTRACTBananas (Musa sapientum, shum.) were dehydrated by immersion in ternary aqueous solutions of sucrose and sodium chloride with different concentrations and temperatures. The temperature (25–55C), sugar concentration (30–60%) and salt concentration (0–10%) of each run were set according to a central composite design. Bananas of the Prata variety were cut into cylindrical pieces of 1.8 cm in diameter and 10 cm in length. Analyses were conducted for moisture, sugar and salt contents. Moisture content was determined by gravimetry in a drying oven according to an Association of Official Analytical Chemists method. Sugar and salt contents were determined by using high‐performance liquid chromatography and conductivity meter, respectively. The results showed that water loss (WL) increased as temperature, salt and sugar concentrations increased. An antagonistic effect has been observed between the two solutes on sugar gain (SG) and on salt gain (SC), and a synergistic effect of the two solutes on WL. The SG was minimal at the minimum levels of the independent variables, and SC was minimized at temperature of 36.3C with concentration of 50% sucrose. Results show that the use of a ternary osmotic solution enhances the WL when compared with the use of binary osmotic solutions.PRACTICAL APPLICATIONSBrazil stands as one of the largest producers of bananas, and among the varieties produced the Prata variety occupies a prominent place. The osmotic dehydration of Cavendish bananas in binary solutions has already been studied, but studies about the Prata variety using ternary systems were not found in the literature. This lack is the main motivation for the present work. The results obtained from this study can be used to optimize osmotic treatment of bananas in industrial scale. Depending on the specific process goals, it is possible to choose from a range of process conditions to direct treatment toward dewatering, impregnation or a mixed effect. The dried bananas can be directly consumed or used as an ingredient in cakes, pastries, candies and many other products. The developed model allows the determination of the amount of water loss and solute uptake in order to predict the different mass transfer flows associated to this process.