Micronutrient flow to the osmotic solution during grapefruit osmotic dehydration

The purpose of this work was to quantify the flow of soluble micronutrients, such as acids, minerals and pectins, from the grapefruit to the osmotic solution (OS) used to dehydrate the fruit when recycling it in successive osmotic dehydration (OD) operations, without reconcentrating. OD was carried out for 3 h at 30 °C with an OS:fruit rate 5:1, using a 55 °Brix sucrose solution. Soluble solids (°Brix), water activity (aw), pH, ascorbic (AA), citric acid (CA), galacturonic acid and major minerals were measured in the fruit and in the OS as a function of the number of uses (up to 8). Electrical conductivity (EC) and viscosity (μ) of the OS were also analysed. The characteristics of the obtained dehydrated grapefruit and the observed recovery of the quantified micronutrient loss by the fruit in the OS allows us to propose the reuse of the OS as a good way of contributing to the economic and ambient profitability of the OD operation. Moreover, its final use as ingredient in new food formulations may be proposed.