The effect of filtrated osmotic solutions based on chokeberry juice enriched with mint extract on volatile compounds in dried apples

Abstract

AbstractThe main objective of the study is to assess the effect of filtration of osmotic solution on the selective penetration during osmotic dehydration and on the retention of volatile compounds, obtained from mint extracts, in apple cylinders cv. Champion after drying using different methods. For this purpose, osmotic dehydration in filtrated and nonfiltrated concentrated chokeberry juice with the addition of mint extract was performed. Then, the process was followed by convective drying, vacuum‐microwave drying, or combined drying methods. Physical properties were determined such as open, closed, total porosity, shrinkage, and water activity. SPME and GC/MS analyses were performed to assess the changes in carvone contribution in the osmotic solutions as well as apple cylinders. Statistical analysis of variance (ANOVA) was also presented. It was found that even though, filtration did not influence osmotic dehydration kinetics, it led to significantly (p <.05) higher carvone contribution in dried material than in the case of nonfiltrated solutions. Convective drying was significantly (p <.05) better in preserving carvone than other drying methods such as vacuum‐microwave drying and combined drying consisting of convective predrying and vacuum‐microwave finishing drying. Drying methods also affected physical parameters like open and closed porosities. Filtration did not influence drying kinetics but resulted in better retention of carvone in dried apples, especially when convective drying was applied.Practical ApplicationsThe study might be of special interest to food processing industry, as it presents new developments (filtration of osmotic solution) in osmotic dehydration that allow to achieve higher contents of volatile compounds (carvone) in dehydrated material after drying compared to conventional osmotic dehydration. The study shows how to work with complex osmotic solutions and obtain high quality dried materials. Obtained results demonstrate that filtration of concentrated juice used as osmotic solution can be applied to affect the selective penetration during osmotic dehydration. Addition of herbal extracts to the osmotic solution can further improve the chemical composition of the dried material and lead to higher contribution of volatile compounds. Osmotic dehydration followed by convective drying results in higher retention of carvone in comparison to other drying methods. The methods presented in the manuscript might be used to create other new compositions with high volatile concentration in the biological material after drying.