The Effect of Filtration on Physical and Chemical Properties of Osmo-Dehydrated Material

Abstract

Osmotic dehydration (OD) performed in concentrated fruit juices used as osmotic solution (OS) comes with some limitations resulting from the material cell structure and is not entirely recognized at the moment. Filtration of the juice could provide some insight into the phenomena occurring throughout the OD. Therefore, the main aim of the study was to recognize the mechanism of selective penetration during OD and evaluate the effect of filtration on physical and chemical properties of osmo-dehydrated material. For this purpose, OD of pumpkin in non-filtrated and filtrated (filters 0.2, 0.45, 0.8, 1.2, 3, 5 and 8 μm) concentrated chokeberry juice was carried out in the study. Moreover, scanning electron microscope (SEM) images were provided. Total phenolic content (TPC) and antioxidant capacity measured by Ferric Reducing Antioxidant Potential (FRAP) and Trolox Equivalent Antioxidant Capacity (TEAC ABTS) of OS and the material were determined. It was found that even though filtration of osmotic solution had a moderate influence on the mass transfer, it greatly affected the chemical composition of dehydrated material. The best option, considering both chemical and physical properties of the dehydrated material, is the use of non-filtrated solution. However, when shorter time of OD is considered, much better results are obtained for filtrated solutions.

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

“…However, samples treated by NF OS exhibited lower values of CA than in the case of 0.2 OS, which can be due to the size of the particles taking part in the process when filtrated solution was applied. This is consistent with the previous studies by Masztalerz et al [ 15 ], who reported significantly higher antioxidant activity of dehydrated apples when filtrated osmotic solution was applied.…”

“…Solid gain (SG), water loss (WL) as well as the water loss to solid gain ratio (WL/SG) and specific energy consumption during drying ( E ODw and E ODm ) are presented in Table 1 . Preliminary studies and a literature review revealed that the most intense mass exchange occurs at the beginning of the process, and therefore, osmotic dehydration was carried out for 30 min [ 15 ]. Due to the application of heterogenic concentrated chokeberry juice with the addition of mint infusion, osmotic solutions were filtrated to remove high molecular weight compounds that could disrupt the mass transfer.…”

“…Champion as well as mint plants were purchased on the local market (Wroclaw, Poland). Concentrated chokeberry juice (Rauch Polska, Płońsk, Poland) was filtrated prior to the experiment according to the method described by Masztalerz et al [ 15 ] using a filter with 0.2 µm pore size. Apples of initial moisture content M C = 87.20% were cut into cylinders (18 ± 0.1 mm × 3.35 ± 0.15 mm).…”

“…Another important factor is size of the openings in the material, which can also significantly affect the osmotic dehydration [ 14 ]. Therefore, filtration of concentrated juice can be successfully applied to remove bigger particles that can hinder the process, and consequently, facilitate the OD, which was previously described by Masztalerz et al [ 15 ], where filtrated chokeberry juice was used as osmotic solution during osmotic dehydration of pumpkin. That study revealed that application of filtrated solutions resulted in an even distribution of solution particles in the material as well as leading to higher antioxidant capacity when filtrated OS was used.…”

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

“…One of the factors influencing the chemical composition during OD is filtration of OS. In the studies by Masztalerz, Figiel, et al (2020) and Masztalerz, Lech, et al (2020) it was found that even though filtration of the concentrated chokeberry juice used as OS had little influence on the drying kinetics it affected total phenolic content and antioxidant activity of the material. Whereas Lech et al (2017) reported that the size of the particles in OS affected polyphenolic content and antioxidant capacity of OSs.…”