Effect of Filtrated Osmotic Solution Based on Concentrated Chokeberry Juice and Mint Extract on the Drying Kinetics, Energy Consumption and Physicochemical Properties of Dried Apples.

Klaudia Masztalerz,Jacek Łyczko,Krzysztof Lech

doi:10.3390/molecules26113274

Klaudia Masztalerz, Jacek Łyczko + Show 1 more

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https://doi.org/10.3390/molecules26113274

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Abstract

Background: Filtration of osmotic solution affects selective penetration during osmotic dehydration (OD), and after drying is finished, this can influence the chemical composition of the material, which is also modified by OD. Methods: Osmotic dehydration was carried out in filtrated and non-filtrated concentrated chokeberry juice with the addition of mint infusion. Then, this underwent convective drying, vacuum-microwave drying and combined convective pre-drying, followed by vacuum-microwave finishing drying. Drying kinetics were presented and mathematical models were selected. The specific energy consumption for each drying method was calculated and the energy efficiency was determined. Results and Discussion: The study revealed that filtration of osmotic solution did not have significant effect on drying kinetics; however, it affected selective penetration during OD. The highest specific energy consumption was obtained for the samples treated by convective drying (CD) (around 170 kJ·g−1 fresh weight (fw)) and the lowest for the samples treated by vacuum-microwave drying (VMD) (around 30 kJ·g−1 fw), which is due to the differences in the time of drying and when these methods are applied. Conclusions: Filtration of the osmotic solution can be used to obtain the desired material after drying and the VMD method is the most appropriate considering both phenolic acid content and the energy aspect of drying.

Highlights

Osmotic dehydration (OD) is a process that occurs when a material is immersed in hypertonic solution and as a result, due to the osmotic pressure between the solution and the material, mass transfer occurs
Filtration of osmotic solution made from concentrated chokeberry juice with the addition of mint infusion did not affect drying kinetics; it affected the selective penetration during osmotic dehydration
A higher number of phenolic acids after drying was found in the samples dehydrated in filtrated osmotic solution regardless of the applied drying method

Summary

Introduction

Osmotic dehydration (OD) is a process that occurs when a material is immersed in hypertonic solution and as a result, due to the osmotic pressure between the solution and the material, mass transfer occurs. The use of this type of osmotic solution comes with some limitations and might disrupt the process due to the heterogenous composition of the juice, which contains a broad spectrum of different molecular weight substances [3]. Bigger particles tend to be stuck on the surface of the material, hindering mass transfer, which was observed in previous studies by Goula et al [12], who performed osmotic dehydration of potatoes in sodium chloride and maltodextrin solutions, and Antonyuk et al [13], who studied the issues concerning agglomeration of particles of different molecular weight. Another important factor is size of the openings in the material, which can significantly affect the osmotic dehydration [14]

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