Influence of some sugars addition on fruit aroma retention during dehydration of fruit products

One of the most important criteria in fruit preservation and processing evaluation relates to the loss or retention of specific flavour compounds, particularly during concentration and drying. Different studies have been performed regarding phenomena related to flavour retention that has been registered in some drying processes and some theories of corresponding mechanisms have been proposed. Flavour retention phenomena in fruit products have also been studied at the Faculty of Food Technology and Biotechnology in Zagreb for several years. Investigations were carried out with fruit purees and model systems, with and without adding some carbohydrates (sugars, pectin) before drying. Some of the results obtained have been discussed and published. Recently, particular attention has been paid to the use of trehalose to prevent flavour loss in fruit purees during freeze and foam-mat drying. Earlier and recent investigations of the authors revealed that the increased fruit volatiles retention due to some sugars addition depends on several factors: physical and chemical properties of sugars added before drying, as well as of flavour compound, i.e. molecular weight and structure, steric and other characteristics connected to different diffusion and sorption ability inside the microstructure.