scholarly journals Ultrasound-assisted osmotic dehydration and convective drying of apples: Process kinetics and quality issues

2016 ◽  
Vol 37 (3) ◽  
pp. 383-391 ◽  
Author(s):  
Dominik Mierzwa ◽  
Stefan J. Kowalski
Keyword(s):  
Osmotic Dehydration ◽  
Colour Change ◽  
Apple Fruit ◽  
Point Of View ◽  
Convective Drying ◽  
Drying Process ◽  
Drying Time ◽  
Ultrasound Enhancement ◽  
Kinetics Of

Abstract 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.

scholarly journals Ultrasound enhancement of osmotic dehydration and drying – Process kinetics and quality aspects

2018 ◽  
Author(s):  
Grzegorz Musielak
Keyword(s):  
Osmotic Dehydration ◽  
Convective Drying ◽  
Drying Process ◽  
Process Kinetics ◽  
Vibration Effect ◽  
Quality Aspects ◽  
Wide Range ◽  
Osmotic Agents ◽  
Ultrasound Enhancement

The aim of presented studies is to investigate of influence of ultrasonic assistance on both osmotic dehydration and convective drying. A wide range of different materials, as well as several osmotic agents were tested. The obtained results show that the use of ultrasound always accelerates the investigated processes. The application of ultrasound may reduce the energy consumption of drying. Qualitative studies of dried materials do not give a definite answer about the effect of ultrasound on the quality of the products. Mathematical modelling of the ultrasound assisted drying indicates that so named “vibration effect” plays the biggest role in convective drying acceleration. Keywords: osmotic dehydration; convective drying;  ultrasound; process kinetics.

scholarly journals Influence of preliminary osmotic dehydration on drying kinetics and final quality of carrot (Daucus carota L.)

2011 ◽  
Vol 32 (3) ◽  
pp. 185-194 ◽  
Author(s):  
Stefan Kowalski ◽  
Dominik Mierzwa
Keyword(s):  
Daucus Carota ◽  
Osmotic Dehydration ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Solid Gain ◽  
Visual Appearance ◽  
Daucus Carota L ◽  
Colorimetric Measurements

Influence of preliminary osmotic dehydration on drying kinetics and final quality of carrot (Daucus carotaL.)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.

scholarly journals Kinetics of Convective Drying and Quality of Pears Cultivars Conference, Lucas, Abate

2012 ◽  
Vol 69 (2) ◽  
Author(s):  
Ionuț VELEȘCU ◽  
Vasile DOBRE ◽  
Ioan ŢENU
Keyword(s):  
Technological Process ◽  
Air Temperature ◽  
Oxidation Process ◽  
Convective Drying ◽  
Maximum Speed ◽  
Drying Process ◽  
Temperature And Humidity ◽  
Kinetics Of

Abstract. The objective of this study is the kinetics process of drying of the pears cv. Conference, cv. Abate and cv. Lucas with a laboratory dryer, in order to identify at which level of humidity the maximum speed of evaporation is achieved and at which level of temperature and humidity pears slices begin to change (colour and shape) and to determine which one of the three tested varieties offers the best properties for drying, which will ensure that the final product is technologically and organoleptically the most acceptable. Drying parameters were the same for all three varieties: 2 hours at air temperature 90oC, 2 hours at air temperature 80oC, 2 hours at air temperature 70 C and 2 hours at air temperature 60o C.  The results showed that the sample of the cv. Conference has undergone the least oxidation process, rounded edges and shriveled slices, and samples of the cv Lucas showed the worst results. Following the drying process of all three varieties, it can be concluded that the cultivars Abate and Conference achieved the lower evaporation speed, unlike the cv. Lucas. The cultivars Conference and Abate have attained consistent drying and in this way the technological process was finished with a smaller temperature, resulting in a better quality of the final product. o

scholarly journals DETERMINATION OF THE ENERGY EFFICIENT MODES FOR BARLEY SEEDS DRYING

2020 ◽  
Vol 61 (2) ◽  
pp. 183-192
Author(s):  
Yu.F. Snezhkin ◽  
V.M. Paziuk ◽  
Zh. O. Petrova ◽  
O.A. Tokarchuk
Keyword(s):  
Energy Efficiency ◽  
Germination Rate ◽  
Initial Moisture Content ◽  
Convective Drying ◽  
Coolant Temperature ◽  
Drying Process ◽  
Two Stage ◽  
Drying Time ◽  
High Germination ◽  
Kinetics Of

For a more accurate study of the kinetics of the barley seeds drying, a convective drying stand with a computerized system of data acquisition and processing on the change in the mass and temperature of the sample from the drying time was used. The kinetic curves of the drying process under the action of three factors were constructed: the temperature of the coolant, heating medium movement rate and the initial moisture content of the seeds. Studies were also conducted and the germination of barley seeds under the action of these factors was analysed. Studies have shown that all factors affect the kinetics of the drying process, but the greatest influence on the germination of seed material comes from the influence of the temperature of the coolant. A three-factor effect on the germination of barley seeds on the 7th day of germination is presented, that indicates the need for low-temperature drying at a coolant temperature of 50°C. In order to increase the intensification and energy efficiency of the drying process, the proposed two-stage drying mode is 65/50°C, which provides intensive heating and evaporation of moisture from the material at the initial stage of the process. Studies on the germination of barley seeds in a two-stage mode showed that the specified drying mode provides a high germination rate of the material up to 99%, an intensity of 83% and an energy efficiency of 62% compared to a rational single-stage drying mode of 50°C and can be recommended for drying barley seeds.

scholarly journals Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 202
Author(s):  
Ivan Pavkov ◽  
Milivoj Radojčin ◽  
Zoran Stamenković ◽  
Krstan Kešelj ◽  
Urszula Tylewicz ◽  
...  
Keyword(s):  
Activation Energy ◽  
Osmotic Dehydration ◽  
Effective Diffusivity ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Kinetics Of

This study aimed to determine the effects of osmotic dehydration on the kinetics of hot air drying of apricot halves under conditions that were similar to the industrial ones. The osmotic process was performed in a sucrose solution at 40 and 60 °C and concentrations of 50% and 65%. As expected increased temperatures and concentrations of the solution resulted in increased water loss, solid gain and shrinkage. The kinetics of osmotic dehydration were well described by the Peleg model. The effective diffusivity of water 5.50–7.387 × 10−9 m2/s and solute 8.315 × 10−10–1.113 × 10−9 m2/s was calculated for osmotic dehydration. Hot air drying was carried out at 40, 50, and 60 °C with air flow velocities of 1.0 m/s and 1.5 m/s. The drying time shortened with higher temperature and air velocity. The calculated effective diffusion of water was from 3.002 × 10−10 m2/s to 1.970 × 10−9 m2/s. The activation energy was sensitive to selected air temperatures, so greater air velocity resulted in greater activation energy: 46.379–51.514 kJ/mol, and with the osmotic pretreatment, it decreased to 35.216–46.469 kJ/mol. Osmotic dehydration reduced the effective diffusivity of water during the hot air drying process. It also resulted in smaller shrinkage of apricot halves in the hot air drying process.

scholarly journals Drying of ‘yacon’ pretreated by pulsed vacuum osmotic dehydration

2021 ◽  
Vol 25 (8) ◽  
pp. 560-565
Author(s):  
Letícia F. Oliveira ◽  
Jefferson L. G. Corrêa ◽  
Paula G. Silveira ◽  
Marina B. Vilela ◽  
João R. de J. Junqueira
Keyword(s):  
Water Activity ◽  
Osmotic Dehydration ◽  
Drying Kinetics ◽  
The Other ◽  
Convective Drying ◽  
Vacuum Drying ◽  
Second Law ◽  
Drying Time ◽  
Different Temperatures

ABSTRACT In this study, the ‘yacon’ was dried using pulsed vacuum osmotic dehydration as pretreatment followed by vacuum drying (at different temperatures) or convective drying. The use of osmotic dehydration and vacuum drying had their influence evaluated concerning drying kinetics and quality of the final product, considering fructan retention, color, and water activity. Fick’s second law and Page’s equation were suitable for the fitting of drying evolution. It was observed that higher temperatures (60 °C) resulted in shorter drying time, higher diffusivity, and higher fructan retention when compared to 40 and 50 °C. The osmotic pretreatment and the vacuum drying differed in fructan retention (p ≤ 0.05). Moreover, the dried product, osmotically pretreated, presented a shorter drying time. The best condition was vacuum drying at 60 ºC, preceded by pulsed vacuum osmotic dehydration that resulted in fructan retention of approximately 38% in a quicker, higher diffusivity and lighter color product concerning the other tested conditions.

scholarly journals The kinetics of nutritional quality changes during winter jujube slices drying process

2021 ◽  
Vol 13 (1) ◽  
pp. 73-82
Author(s):  
Yubao Niu ◽  
Shiyu Wei ◽  
Huan Liu ◽  
Yongzhen Zang ◽  
Yuxue Cao ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Weibull Model ◽  
Reducing Sugar ◽  
Total Acidity ◽  
Drying Process ◽  
Drying Time ◽  
Nutrient Quality ◽  
Air Impingement ◽  
Weibull Models ◽  
Kinetics Of

The purpose of this research is to investigate the kinetics of nutrient quality (Vitamin C (Vc), reducing sugar and total acidity) change of winter jujube slices that under different drying temperatures (55, 60, 65 and 70?) and different air velocities (3, 6 and 9m/s) during the air-impingement drying process. Results showed that the content of Vc, reducing sugar and total acidity decreased with increasing drying time. Furthermore, analysis of variances indicated that the drying temperature, air velocity and time had a significant effect on the loss of Vc, reducing sugar and total acidity (p<0.05). Zero order, first order and Weibull models were used to fit the experimental data, Weibull model was considered as the most suitable one to the degradation kinetics of Vc, reducing sugar and total acidity in dried samples at different temperatures and air velocities. According to the Arrhenius formula, the activation energy of Vc, reducing sugar and total acidity degradation kinetics were 63.78 kJ/mol, 36.48 kJ/mol and 153.51 kJ/mol, respectively. This research can provide some references for enhancing dried products quality in the jujube drying industry.

scholarly journals Mathematical modeling of pequi pulp drying and effective diffusivity determination

2017 ◽  
Vol 21 (7) ◽  
pp. 493-498 ◽  
Author(s):  
Elisabete P. de Sousa ◽  
Rossana M. F. de Figueirêdo ◽  
Josivanda P. Gomes ◽  
Alexandre J. de M. Queiroz ◽  
Deise S. de Castro ◽  
...  
Keyword(s):  
Experimental Data ◽  
Effective Diffusivity ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Air Speed ◽  
Drying Curves ◽  
Increasing Temperature ◽  
Kinetics Of ◽  
Best Fit

ABSTRACT The aim of this work was to study the drying kinetics of pequi pulp by convective drying at different conditions of temperature (50, 60, 70 and 80 °C) and thickness (0.5, 1.0 and 1.5 cm) at the air speed of 1.0 m s-1, with no addition of adjuvant. The experimental data of pequi pulp drying kinetics were used to plot drying curves and fitted to the models: Midilli, Page, Henderson & Pabis and Newton. Effective diffusivity was calculated using the Fick’s diffusion model for a flat plate. It was found that, with increasing thickness, the drying time increased and, with increasing temperature, the drying time was reduced. The Midilli model showed the best fit to the experimental data of pequi pulp drying at all temperatures and thicknesses, presenting higher coefficients of determination (R2), indicating that this model satisfactorily represents the pequi pulp drying phenomenon. There was a trend of increase in the effective diffusivity with the increase in pulp layer thickness and temperature.

scholarly journals Effect of Solar Radiation on the Drying Parameters of Mint (Mentha Spicata L.) Dried in Natural Convective Solar Dryer

2020 ◽  
Author(s):  
SEBIHA REHMAN ◽  
SEEMIN RUBAB
Keyword(s):  
Weather Conditions ◽  
Quality Parameter ◽  
Drying Process ◽  
Kashmir Valley ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Mentha Spicata ◽  
Solar Dryer ◽  
Pre Treatment ◽  
Kinetics Of

Abstract The paper presents a kinetic study of solar dried mint (Mentha spicata L.) without any pre-treatment. Mint grows effortlessly in Kashmir valley but is not obtainable throughout the year because of inconsiderate weather conditions. The genus belongs to the Labiatae family and includes large varieties with different properties. A significant quality parameter is its colour. The drying kinetics of mint leaves dried in Domestic Solar Dryer in terms of colour attributes, moisture content, drying time, non enzymatic browning, water activity, rehydration ratio was studied. This study is very useful for household scale drying of mint leaves to optimize drying process and to achieve superior quality dried product at home maintaining its colour and aroma.

scholarly journals Physicochemical Properties of Dried Apple Slices: Impact of Osmo-Dehydration, Sonication, and Drying Methods

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1078
Author(s):  
Joanna Cichowska-Bogusz ◽  
Adam Figiel ◽  
Angel Antonio Carbonell-Barrachina ◽  
Marta Pasławska ◽  
Dorota Witrowa-Rajchert
Keyword(s):  
Physicochemical Properties ◽  
Osmotic Dehydration ◽  
Convective Drying ◽  
Drying Methods ◽  
Drying Method ◽  
Drying Time ◽  
Hygroscopic Properties ◽  
Fruit Samples ◽  
Apple Slices ◽  
Pre Treatment

Apple slices of the Elise variety were previously osmo-dehydrated in erythritol, xylitol, and sucrose for 2 h. In some parts of the experiment, 30 min of ultrasound pre-treatment (US) were applied. Afterwards, fruit samples were dried by convective (CD), microwave-vacuum (VM), and a combined method (CD/VM, mix two of them). The main aim of the research was to characterize an impact of osmotic dehydration, sonication pre-treatment, and drying method on the physicochemical properties of the dried apples. The use of sugar alcohols (xylitol, erythritol) in the production of dried apples did not badly affect the taste of the obtained dried products; it enabled a noticeable cooling/refreshing effect felt in the mouth when consuming a snack, and enabled the production of dried snacks with lower calorific value. Polyol residues in the product were at a level that was safe for consumers. The most popular convective drying was long lasting, whereas the VM drying method allowed for the shortest drying time, amounting to 76 min; moreover, additional application of ultrasounds reduced this time to 36 min. The combined drying method allowed the total duration of the process to be reduced 2–4.5 times. Ultrasound applied during osmotic dehydration did not significantly affect attributes of the descriptive sensory analysis for the obtained dried apples. The best hygroscopic properties, ensuring the storage stability of the dried product, showed dried apples previously osmo-dehydrated in erythritol and sucrose solutions.

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