Dried mango enriched with isomaltulose by using ultrasound and pulsed vacuum in osmotic dehydration with subsequent drying

Abstract

Mango (Mangifera indica L. cv. Tommy Atkins) is one of the most popular tropical fruits. It is a climacteric and perishable fruit, which need specific care for its conservation. Osmotic dehydration (OD) and drying are among the techniques that can improve the stability of the fruit. The carbohydrates, such as sucrose, are commonly applied in OD. However, replacing this sugar by healthier ones is required. Isomaltulose, commercially known as Palatinose®, is a reducing disaccharide that has physicochemical and sensory properties very similar to those of sucrose, with the following advantages: non-cariogenic, low glycemic and insulinemic indexes. The aim of this study was enriching mangos with isomaltulose through OD processes – in addition to the use of technologies such as ultrasound and pulsed vacuum, in order to evaluate the influence of these processes and subsequent drying on the physical, chemical nutritional and hygroscopic characteristics of the product. Moreover, studies about the isomaltulose properties in aqueous solutions, osmotic processes at different solutes type, temperatures and solute concentrations; and hygroscopicity and thermodynamic sorption properties were also carried out in this research. The main results highlighting that: isomaltulose can be promising in the replacement of sucrose in osmotic processes. the OD kinetics were represented with good accuracy by linearized Azuara model; the best conditions for incorporation of isomaltulose in mangos, according to multilevel models, were 45 °C and 35% solute concentration; vacumm assays showed that the use of 10 min and 48 kPa of absolute pressure promoted greater fruit enrichment, and best physicochemical characteristics in relation to higher vacuum and time levels; the incorporation of isomaltulose by ultrasound and pulsed vacuum before drying resulted in more stable product, from a hygroscopic point of view, besides the best quality properties; and the thermodynamic approach showed that the enthalpy and entropy behaviors showed interaction between water and the product components, which was similar to physical properties of pure water from 0.35 g water/g dry matter. Gibbs free energy value indicated that sorption of fresh mango was a non-spontaneous process, while for pretreated with sucrose and isomaltulose were spontaneous processes. The enthalpy-entropy compensation theory indicated the sorption processes of all products were enthalpy-controlled.