Effect of Osmotic Dehydration on Physico-Chemical Characteristics, Bioactive Compounds and Volatiles Profile of Diospyros kaki Subjected to Different Drying Methods.

The seasonality of Diospyros kaki limits its consumption, making it increasingly necessary to develop products that allow it to be available all year round. Therefore, the aim of this study was to optimize the osmotic dehydration process and to evaluate the changes in the physico-chemical, bioactive and volatile composition of persimmon subjected to drying. A central composite rotatable design was used with the independent variables as sucrose concentration (%) and immersion time (min). The desirability function for sucrose solution concentration and immersion time was 29.5% for 60 min for hot air oven drying and 38% for 29 min for freeze drying. The dehydrated fruit treated with osmotic pretreatment showed better responses in the quantification of bioactive compounds and retention of volatile compounds. Compounds such as nonanal and 6-methyl-5-hepten-2-one were identified in all the dehydrated products and the OD had a positive influence on their retention, especially for the lyophilized samples. Thus, it is clear that osmotic pretreatment is an ally in protecting the physico-chemical and chemical characteristics of the fruit when it undergoes a drying process, especially with regard to bioactive and volatile compounds.