Quality and sustainability in dehydration processes

Abstract

The general objective of this project was the identification of applicable pretreatments on fruit and vegetable products in order to reduce the loss of nutritional components during the dehydration process and, at the same time, to reduce the residence time of the product during the process itself. Through the study carried out, it was possible to define a prototype of a smart dehydrator. In the future, this prototype will have to be further implemented in order to make it usable on an industrial level. Specific objectives of this experimentation are the monitoring and consequent optimization of the hot air flow dehydration process, considering organic carrots as products (cv. Romance and Carvejo). In order to achieve the intended purpose, the effects of some pre-treatments (thermal, dipping and vacuum impregnations techniques) aimed at reducing the dehydration time and improving the final quality of the plant matrices subjected to the process were investigated. The analytical techniques used for the analysis were: the peroxidase enzymatic activity assay (POD), the colorimetric analysis, the determination of the total phenol content, the extraction and quantification of carotenoids, the analysis of the rehydration and determination of the dry matter content. The monitoring of chemical-physical changes of the products (e.g. moisture content, water activity, soluble solids, titratable acidity, phenolic content, carotenoid content, consistency and color changes) was conducted taking into account the operational parameters that influence dehydration (temperature, air speed and relative humidity). In addition, four mathematical models were employed to describe the kinetics of dehydration. The ultimate goal of the design activity is the transfer of the monitoring and control system to a dryer prototype...