scholarly journals Impact of packing density on primary drying rate

2020 ◽  
Vol 13 (2) ◽  
pp. 30-37
Author(s):  
Anna Matejčíková ◽  
Pavol Rajniak
Keyword(s):  
Packing Density ◽  
Gravimetric Method ◽  
Drying Rate ◽  
Sublimation Rate ◽  
Drying Time ◽  
Freeze Dryer

Abstract This work aimed to determine the effect of packing density on the sublimation rate in a laboratory freeze dryer. Total amount of sublimed water was determined by gravimetric method while a total of seven experiments were performed under the same conditions (pressure, temperature, and drying time), at different configuration of the vials. The experiments confirmed that the higher the packing density, the lower the drying rate, and vice versa, the lower the packing density, the higher the drying rate. The effect of vials packing density was confirmed by experiments using a plastic rack, while the vials were separated and thus the packing density was lower. In this case, the drying rate was more homogeneous, which contributes to the higher quality of the final product.

scholarly journals Physiological and sensorial quality of Arabica coffee subjected to different temperatures and drying airflows

2017 ◽  
Vol 39 (2) ◽  
pp. 225 ◽  
Author(s):  
Guilherme Euripedes Alves ◽  
Flávio Meira Borém ◽  
Eder Pedroza Isquierdo ◽  
Valdiney Cambuy Siqueira ◽  
Marcelo Ângelo Cirillo ◽  
...  
Keyword(s):  
Germination Percentage ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Drying Time ◽  
Physiological Variables ◽  
Different Temperatures ◽  
Negative Effect ◽  
Physiological Quality ◽  
Sensorial Quality

The objective of this study was to evaluate the correlation between a group of physiological variables (electrical conductivity, potassium leaching, and germination percentage) and a group of drying kinetics variables (drying time and drying rate) in addition to verifying the relation between drying kinetics variables and coffee quality as a function of processing type, temperature, and drying airflow. Coffee drying was conducted in a fixed-layer dryer at two temperatures and two airflows. After drying, an evaluation of the physiological and sensorial quality was conducted. Based on the results obtained, the following conclusions were drawn: coffee that is processed via a dry method is more sensitive to mechanical drying with heated air than coffee processed via a wet method, resulting in poor physiological performance; airflow does not interfere with the physiological quality of pulped and natural coffees; a temperature increase from 40 to 45°C resulted in a decrease in the physiological quality only for pulped coffee; and an increase in the drying rate as a result of an increase in the drying temperature to 40°C had a negative effect on the sensorial quality of pulped coffee. 

scholarly journals The using Infrared Radiation on the Freeze-Drying of Cherry

2020 ◽  
Vol 9 (2) ◽  
pp. 1628-1630
Keyword(s):  
Energy Consumption ◽  
Infrared Radiation ◽  
Freeze Drying ◽  
Experimental Studies ◽  
Quality Characteristics ◽  
Drying Rate ◽  
Drying Time ◽  
Reduce Energy Consumption ◽  
Pre Treatment ◽  
Freeze Dryer

In this work experimentally investigated the drying rate of Cherry on the freeze-dryer (FD) and FD with infrared pretreatment (IR), and compared the quality characteristics of the cherry after rehydration. Results of experimental studies was determined that, the use of IR pre-treatment on the FD was much more effective. The use of IR waves showed that the drying time of cherries with IR pre-treatment is shorter than without pre-treatment. Especially, the application of IR pretreatment before freeze-drying, allows you to get quality products, and provides to reduce energy consumption by 15-17%.

scholarly journals A study of drying parameters on drying time and colour quality of grated coconut using tumbling mechanism in convective dryer

Food Research ◽  
2020 ◽  
Vol 4 (S6) ◽  
pp. 64-69
Author(s):  
S. Yahya ◽  
A. Mohd Shahrir ◽  
M.A. Amir Syariffudden ◽  
A. Shafie ◽  
J. Mohammad Shukri ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Small Scale ◽  
Drying Rate ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Significant Difference ◽  
Main Factors ◽  
Drying Behaviour

A small scale convective dryer with tumbling mechanism was specially constructed for drying grated coconut. This new drying mechanism was evaluated in term of drying behaviour and colour quality of the final product. Three main factors that involved were hot air temperature, rotational speed (rpm) and air velocity. Every combined parameter of a sample was compared to each other and also with freshly grated coconut. It was found that the combination of 60°C, 6 rpm and 4.31 ms-1 had the shortest drying time as well as the highest drying rate among other combinations. In contrast, combination factors of 50° C, 3 rpm and 2.06 ms-1 had the lowest drying rate. Three main factors; temperature, rotational speed and air velocity were significantly contributed to the response of drying time as (p<0.05). Drying rate also increased with increase in temperature, rotational speed and air velocity. In term of colour analysis (L*, a*, b*), there was a significant difference among dried grated coconut samples. Nevertheless, sample 60˚C, 3 rpm and 4.31 ms-1 and 50˚C, 3 rpm and 4.31 ms-1 showed no significant different (p>0.05) in lightness when compared to freshly grated coconut hence excellent in retaining its original appearance. On top of that, sample (60˚C, 3 rpm and 4.31 ms-1 ) also achieved considerable drying rate with an acceptable drying time of 135 mins.

scholarly journals Drying characteristics and quality of lemon slices dried undergone Coulomb force assisted heat pump drying

2018 ◽  
Author(s):  
S. K. Chin ◽  
Y. H. Lee ◽  
B. K. Chung
Keyword(s):  
Vitamin C ◽  
Heat Pump ◽  
Coulomb Force ◽  
Total Phenolic ◽  
Drying Rate ◽  
Total Energy Consumption ◽  
Drying Time ◽  
Drying Characteristics ◽  
Heat Pump Drying

In this research, a Coulomb force assisted heat pump (CF-HP) dryer was invented for the purpose of improving the drying characteristics and product quality of biomaterials. As compared to heat pump drying alone, the assistance of Coulomb force in heat pump dryer enhanced the drying rates and effective moisture diffusivity of lemon slices up to 26%, which eventually shortened the total drying time to 40%. This saved the total energy consumption of HP drying by 31.5%. High retention of vitamin C and TPC were also found in CF-HP dried slices due to mild drying temperature and fast drying rate. Keywords: Coulomb force; Heat pump drying; Drying rate; Vitamin C; Total Phenolic Content (TPC).  

scholarly journals Hybrid and intermittent drying of carrot (Daucus carota var. Nantes)

2018 ◽  
Author(s):  
Dominik Mierzwa ◽  
Justyna Szadzińska ◽  
Krzysztof Bukowski
Keyword(s):  
Mass Transfer ◽  
Convective Drying ◽  
Drying Rate ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Intermittent Mode ◽  
Airborne Ultrasound

A combination of high power airborne ultrasound and microwaves in hot air drying was developed to investigate the effect of intermittent mode on process effectiveness and quality of carrot. The drying experiments were carried out in an innovative hybrid dryer. The course of moisture ratio, drying rate, specific energy and water consumption, colour, water activity and shrinkage were discussed. The results showed that intermittent ultrasound and microwaves in convective drying accelerate the heat and mass transfer, leading to shorter drying time and faster drying rate. It was found that hybrid-intermittent drying can improve the energy efficiency and product quality. Keywords: intermittent drying; ultrasound; microwaves; energy; shrinkage

scholarly journals Drying Characteristics of Jackfruit and Snake Fruit using Freeze Dryer

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Joko Nugroho Wahyu Karyadi ◽  
Siti Rahma ◽  
Ronal Sitindaon ◽  
Dionisia Gusda Primadita Putri ◽  
Dwi Ayuni
Keyword(s):  
Ascorbic Acid ◽  
Moisture Content ◽  
Acid Content ◽  
Heating Temperature ◽  
Ascorbic Acid Content ◽  
Drying Rate ◽  
Order Kinetic ◽  
Drying Time ◽  
Freeze Dried ◽  
Freeze Dryer

Jackfruit (Artocarpus heterophyllus Lam.) and snake fruit [Salacca zalacca (Gaert.) Voss] are tropical fruits that are rich in vitamins and minerals. Due to their specific aroma and unique taste, jackfruit and snake fruit have great potential to be processed into dried fruits and healthy snacks. In this work, jackfruit and snake fruit were freeze-dried using a self-designed laboratory-scale freeze dryer. The freeze dryer was constructed with a stainless-steel plate (3 mm thickness). The drying rates were determined with three different heating temperatures: 50, 60, and 70ºC. This study also investigated the effect of the freeze-drying process on the characteristics of dried fruit such as moisture content, texture, color, ascorbic acid content, and morphological of dried samples. Results showed that the heating temperatures were revealed to affect characteristics such as drying rate, final moisture content, texture, and ascorbic acid content. Increased drying rate and decreased drying time were observed with an increase in the dryer temperature. The sample resulted from 70ºC of heating temperature exhibited the optimum results in terms of hardness and ascorbic content preservation. The first-order kinetic model was the best fit for the prediction of drying kinetics of all materials.

scholarly journals Optimizing Dehydration Conditions of Cow's and Goat Milk Yogurt Powder

2020 ◽  
Vol 9 (3S) ◽  
pp. 68-71
Keyword(s):  
Goat Milk ◽  
National Standard ◽  
Drying Method ◽  
Drying Time ◽  
Excellent Method ◽  
Fermented Dairy Products ◽  
Fermented Dairy ◽  
Freeze Dryer ◽  
Microbiological Properties

Yogurt is one the importance the most common fermented dairy products widely consumed worldwide, mmostly studies are about in how to longer the yogurt shelf life, this study purposed to drying cow and goat milk yogurt by freeze dryer to provide alternative method don't have effect on yogurt compounds and lactic acid bacteria cell, and to identification the influence of stirring and time on yogurt powder compounds, the International Official Analytical Chemistry Association (AOAC) and the Indonesian National Standard (SNI) methods were used to analyze the chemical composition of yogurt powder, Cow’s and goat milks were mixed in rate 25:75 (v/v), inoculum with culture 15% (v/v) S. therophillus, L. acidophilus, L. burgaricus (1:1:1), and incubated at 46oC for 8h.Yogurt was dryed by freeze dryer at -73oC for 16, 19, and 22hours on 4, 5, and 3 batches with stirring respectively, The results obtained from this study that the best drying method of cow and goat yogurt treated by freeze dryer was19h., drying by freeze at batches with stirring have no significant effect on amount of bacteria cells, moreover, it is an excellent method to preserve the desirable microbiological properties in yogurt, and decreased the drying time and improving quality of final product.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

scholarly journals Effects of different drying rates on the physiological quality of Coffea canephora Pierre seeds

2005 ◽  
Vol 17 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Sttela Dellyzete Veiga Franco da Rosa ◽  
Delacyr da Silva Brandão Júnior ◽  
Édila Vilela de Resende Von Pinho ◽  
André Delly Veiga ◽  
Luiz Hildebrando de Castro e Silva
Keyword(s):  
Water Content ◽  
Storage Temperature ◽  
Removal Rate ◽  
Coffea Canephora ◽  
Development Stage ◽  
Seed Vigor ◽  
Drying Rate ◽  
Physiological Quality ◽  
Drying Rates

Desiccation tolerance in seeds depends on the species, development stage and drying conditions, especially the water removal rate. Coffea seeds are considered of intermediate performance, because they tolerate relative dehydration compared to orthodox seeds and are sensitive to low temperatures. The objective of this study was to verify the effect of different drying rates on the viability and storability of Coffea canephora seeds. A complete randomized experimental design was used, in a factorial 3 x 5 x 2 design, with three drying rates (fast, intermediate and slow), five final mean water contents after drying (51, 42, 33, 22 and 15 %) and two storage temperatures (10 and 20°C). The germination and seed vigor assessments, using radicle protrusion, cotyledon leaf opening, seedling emergence and emergence speed index, were performed shortly after drying and after two and four months storage. It was observed that with reduction in the water content there was reduction in the germination values and seed vigor, for all the drying rates. The greatest reductions in physiological quality occurred when the seeds were dried quickly and the best results were obtained at the intermediate drying rate. There was an effect of drying rate and storage temperature on the physiological quality of the seeds, and lower germination and vigor values were observed in seeds with lower water content stored at 20°C. C. canephora seeds were tolerant to desiccation down to 15 % water content and can be stored for four months at 10°C. A temperature of 20ºC can be used to store C. canephora seeds, as long as the water content is not reduced to values below 22 % water content.

scholarly journals The Quality of Red Bell Pepper Subjected to Freeze-Drying Preceded by Traditional and Novel Pretreatment

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 226
Author(s):  
Katarzyna Rybak ◽  
Artur Wiktor ◽  
Dorota Witrowa-Rajchert ◽  
Oleksii Parniakov ◽  
Małgorzata Nowacka
Keyword(s):  
Freeze Drying ◽  
Bell Pepper ◽  
Total Phenolic ◽  
Thermal Methods ◽  
Drying Time ◽  
Freeze Dried ◽  
Dehydration Processes ◽  
Vacuum Freezing ◽  
Better Than

It has been demonstrated previously in the literature that utilization of PEF or a combination of a pulsed electric field (PEF) and ultrasounds (US) can facilitate dehydration processes and improve the quality of dried products even better than the application of thermal methods such as blanching. The aim of the study was to evaluate the quality of red bell pepper subjected to freeze-drying preceded by blanching or PEF or US treatment applied in a single and combined mode. Furthermore, the freeze-drying was preceded by shock freezing or vacuum freezing performed inside the freeze-dryer as a result of pressure drop during the first stage of freeze-drying. All of the analyzed technological variants enhanced the drying kinetics when compared to the intact material. Freeze-dried bell pepper subjected to non-thermal pretreatment exhibited higher vitamin C, total phenolic and carotenoids content than blanched material despite the fact that blanching reduced drying time the most compared to all other analyzed methods.

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