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In this study, the effect of various drying methods on the rehydration behaviour and mass transfer diffusion coefficients of squid (Loligo vulgaris) is investigated. Drying methods were selected as infrared (IR), ultrasonic pre-treated infrared (US-IR) and microwave (MW). In IR and US-IR method drying temperatures were within 60 - 80 °C and in MW drying the power levels were in between 140 - 350 W. The rehydration process was carried out for all samples in 180 minutes at room temperature with 30-minute weighing intervals. Obtained rehydration data were applied to the mathematical models of Peleg and Two-Term Exponential. The rehydration ratios were changed between 1.78 - 2.50, 1.91 - 2.66 and 2.78 - 3.83 g/g dry matter for IR, US-IR, and MW respectively. Mass transfer diffusion coefficients of effective moisture diffusion (Deff) values were changed between 1.01 × 10-7 - 1.07 × 10-7, 1.02 × 10-7 - 1.08 × 10-7, and 1.12 × 10-7 - 1.22 × 10-7 m²/s, for IR, US-IR, and MW respectively. Peleg and Two-Term Exponential mathematical models showed matched well with the experimental data. In addition, colour values found to be changed particularly in the brightness values due to rehydration process. [ABSTRACT FROM AUTHOR]

The effects of concentrated fruit juices on mass transfer and enhancement of health-promoting properties of apple slices treated by an osmotic dehydration process with (PVOD) and without (OD) a vacuum were investigated. Hot air-drying (AD) was used as the finish drying process to produce apple chips. The apple chips obtained by OD + AD and PVOD + AD with grape juice had a total phenol content (TPC) of 81.54 ± 3.66 and 86.09 ± 1.23 mg GAE/100 g of dry matter, respectively, significantly higher than that (24.99 ± 0.46 mg GAE/100 g dry matter) of the chips from fresh apples (control). Similarly, DPPH radical–scavenging activity values of the OD + AD and PVOD + AD chips treated with grape juice were 78.44 ± 3.02% and 81.13 ± 2.47%, respectively, significantly higher than that of the control (26.06 ± 0.53%). The dehydration rate in the OD and PVOD processes was positively correlated with the osmotic pressure difference (Δπ) between the osmotic solution and the apple tissue following an exponential relation, and thus, Δπ has functioned as the driving force for mass transfer in the OD and PVOD processes. Concentrated fruit juices are shown to be effective osmotic solutions to produce colorful apple chips with enhanced health-promoting properties. [ABSTRACT FROM AUTHOR]

Salted chickpea (Cicer arietinum L.) is increasingly used in snack production and in home cooking by soaking in brines. Order to achieve better quality and higher nutrient content, it is important to model and understand the mass transfer processes during this operation. In this work, brine salting of chickpea was studied at 1, 5 and 20% salt concentrations, at temperatures of 25, 50, 75 and 100 °C. Water uptake, salt uptake and non-ash solids loss over time were modeled using the Peleg, Fickian diffusion and anomalous diffusion models. Salt content of brines significantly affects the changes occurring during chickpea soaking. At 1% salt content, the volume gain is larger than when soaking in water, while at 5 and 20% swelling decreases, with a lower solids' loss. The fit of each model to experimental data was assessed using the Coefficient of Determination, the Root Mean Square Error, the Akaike Information Criterion, and the errors of the fitted parameters of each model. The results show that the Fick model is at least as good as the Peleg model in predicting the mass transfer of each considered component, but the influence of the equilibrium parameter is more clear on the Peleg model, resulting in better forecasts of the kinetic parameter. The anomalous diffusion model was not adequate to fit neither the water, the salt nor the solids loss, resulting in large errors in both the diffusion coefficient and the equilibrium parameter. [ABSTRACT FROM AUTHOR]

Osmotic dehydration of fruits and vegetables is a slow process due to resistance in mass transfer (MT). This resistance can be modified by varying the osmotic solution or process conditions, or by employing non-thermal treatments (NTT). Some NTT modify the tissue structure by formation of pores in the cell membrane (such as pulse electric fields) or microchannels (such as ultrasound and osmosonication), and others increase the contact surface area with the tissue through a decrease in atmospheric pressure (such as vacuum pulses) or an increase of the system pressure (such as high hydrostatic pressures). Changes in the rate of MT caused by modifications in experimental conditions can be described with mathematical models, such as Fick's second law. The aims of this review are to analyze the different factors that modify MT rate during osmotic dehydration, examine the application of NTT to modify MT, and to study models that describe these processes. [ABSTRACT FROM AUTHOR]

Abstract: Hydration is a crucial step during grain processing. It is performed prior to many other processes, such as germination, cooking, extraction, malting and fermentation. The number of publications on this topic studying the description of the mechanisms involved and recent technologies for processing enhancement has increased recently. However, due to the complexity of the hydration process, there are still many aspects that are little understood. For that reason, this review provides not only an overview of recent developments in this field, but also a critical discussion of publications from the last 2 decades, as well as suggestions for future innovative studies. This review discusses the importance of hydration in the grain industries, the pathway for water entry into the various grains, the mass transfer and fluid flow mechanisms in the process, the behavior of the hydration kinetics, the mathematical modelling, the technologies used to accelerate the process and other necessary requirements that must be performed to complement and complete our knowledge of this process. [ABSTRACT FROM AUTHOR]