The aim of the present theme issue was to study the influence of ultrasound enhancement on the kinetics of osmotic dehydration and the effect of convective drying from the point of view of drying time and quality of dried products. Apple fruit was used as the experimental material. The kinetics of osmotic dehydration with (UAOD) and without (OD) ultrasound enhancement were examined for 40% fructose and sorbitol solutions. The effective dehydration time of osmotic process was determined. Preliminary dehydrated samples with OD and UAOD were next dried convectively with (CVUS) and without (CV) ultrasound assistance. The influence of OD and UAOD on the kinetics of CV and CVUS drying was analysed. The parameters of water activity and colour change were measured for the assessment of product quality after drying process.
The paper is focused on the main problems of modern metrology in the context of the Fourth Industrial Revolution “Industry 4.0”, particularly in the field of qualimetry. The dominant issues of the methodology of qualimetrical measurement, as the interrelation between metrology and qualimetry, are considered. The following questions are raised and analysed: determination of the measurand in the qualimetrical measurement, creation of the virtual product quality pattern, determination of the product quality level by using the theory of multidimensional scaling, assurance of the metrological traceability of the qualimetrical measurement results. A procedure of performing the qualimetrical measurement is described.
This paper concerns convective drying of carrot preliminary dehydrated in aqueous solutions of three types of osmotic agents (sucrose, fructose, glucose). Three solution concentrations (20, 40 and 60%) were examined to work out efficient conditions of osmotic dewatering. The parameters such as water loss (WL), solid gain (SG) and osmotic drying rate (ODR) indicating the real efficiency of osmotic dehydrations (OD) were determined. The samples dehydrated with osmotic solutions underwent further convective drying to analyze influence of dehydration process on drying kinetics and final products quality. The quality of products was assessed on the basis of visual appearance of the samples and colorimetric measurements. It was found that osmotic pretreatment improves significantly the final product quality as the samples were less deformed and their colour was better preserved compared to samples, which had not been preliminarily dehydrated. Preliminary dehydration, however, did not influence significantly the overall drying time of the samples.
This article presents experimental studies on drying kinetics and quality effects of red beetroot (Beta vulgaris L.) after convective drying with a preliminary osmotic pretreatment. The effects of the osmotic agent (NaCl) concentration and the osmotic bath time on the product colour and nutrient content preservation, the water activity, and rehydration ability after drying were analysed. Osmotic dehydration curves and Solid Gain (SG), Water Loss (WL), Weight Reduction (WR) were determined. It was proved that drying of beetroot with osmotic pretreatment contributes to shorter drying time, smaller water activity, higher retention of betanin, better colour preservation, and a greater degree of water resorption.
Production processes at KGHM are complex and require from customers products of constantly higher quality at relatively lowest prices. Such situation results in an increase of the importance of optimisation of processes. As products and technologies change rapidly, technologists at the plant in Głogów have less time to achieve optimisation basing on own experiences. Analysing a particular process, we can e.g. detect occurring disturbances, find factors having an influence on quality problems, select optimal settings or compare various production procedures. Analysis of the course of production process is the basis of process optimisation. One optimisation in case of the process of decopperisation of flash slag can be a change of a technological additive to a less energy-consuming one, and its final result can be an improvement of the productivity index, a change of the relation between final effects and born expenditures, as well as optimisation of production costs.
This article presents a quality analysis of convectively dried fruits and vegetables with preliminary osmotic dehydration. Tests were carried out on banana fruit and red beetroot samples. Hypertonic solutions of fructose for the banana and those of sucrose for the red beetroot were used, each one at three different concentrations. After osmotic dewatering treatment conducted at different time intervals and after osmotic dehydration the samples were dried convectively until an equilibrium with the surroundings was attained. Osmotic dehydration and convective drying curves were determined. The values of Solids Gain (SG), Water Loss (WL) and Weight Reduction (WR) were measured and changes in the samples’ colour and shape after convective drying with and without osmotic pretreatment were assessed.