Tag Archives: drying

xxx O. Zavadska, І. Bobos, I. Fedosiy, H. Podpriatov, O. Komar, B. Mazur and J. Olt
Suitability of various onion (allium cepa) varieties for drying and long-term storage
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Suitability of various onion (allium cepa) varieties for drying and long-term storage

O. Zavadska¹, І. Bobos¹, I. Fedosiy¹, H. Podpriatov¹, O. Komar¹, B. Mazur¹ and J. Olt²*

¹National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., UA 03041 Kyiv, Ukraine
²Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi Str., EE 51006 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

In the paper, the results are presented obtained in the research into the fresh bulbs and the dried products of 9 onion varieties cultivated in the conditions of the Ukrainian Forest Steppe area with regard to their economical biology, biochemical, marketability and organoleptic indices. The varieties that are most suitable for convection drying and long-term storage have been identified. It has been established that the marketability of both the fresh bulbs and dried products depends on the masses of the bulbs. The Bronze d’Amposta and Harmony varieties deliver the greatest amount of marketable output (94.0 and 93.2%) featuring marketable bulbs with masses of 67.4 g and 70.4 g, respectively (r = 0.82). As the bulb mass increases, the amount of non-standard (r = 0.81) and small (r = 0.76) particles in the dried product decreases substantially. It has been found that the content of solid matter and sugars in fresh bulbs has effect on the yield and quality of the dried and reconstituted products. The Harmony and Skvirskaya varieties, the bulbs of which during the vegetation season build up 12.9% and 13.8% of solid matter, respectively, are distinguished by the highest dry product yield – 17.1 and 16.8%, respectively. Correlation has been established between the contents of solid matter and sugars in fresh bulbs (r = + 0.58). During the tasting of reconstituted onion products, the highest scores were awarded to the samples produced from the Skvirskaya and Harmony varieties – 7.0 points each on the 9-point scale, as their bulbs had accumulated over 7.0% of sugars (total). Judging by the aggregate of the researched indices, the Harmony and Skvirskaya varieties of onions are the most suitable for convection drying. It has been established that the preservation of onions in the conditions of stationary buried storage without artificial cooling depends on the duration of storage and the specific varietal features. Within the five months of the test storage, the preservation of bulbs of all the varieties was high and varied within the range of 80–93%. Longer storage is expedient only in case of the Harmony, Skvirskaya and Gospodinya, for which the bulb preservation rates for a seven month storage period has been shown to be equal to 90.2, 88.4 and 87.2%, respectively. It has been proved that the quantity of healthy bulbs depends to a significant extent on the solid matter content in the bulbs (r = 0.93).

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638–647 T. Ziegler and T. Teodorov
Airflow resistance of two hop varieties
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Airflow resistance of two hop varieties

T. Ziegler* and T. Teodorov

Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Department of Postharvest Technology, Max-Eyth-Allee 100, DE14469 Potsdam, Germany
*Correspondence: tziegler@atb-potsdam.de

Abstract:

The quality of hops used in brewing is substantially reliant upon the processing step of drying. To ensure effective drying in kiln as well conveyor-belt dryers, homogeneous distribution of air is of particular importance. Uneven air distribution often results in inefficient drying and nonuniform moisture content of the hop cones. The air distribution naturally is governed by the airflow resistances in the individual floors or belts of a dryer. Hence, in order to quantify the airflow resistance of hop cones at different air velocities and bed heights, systematic measurements were carried out. In addition to determining the bulk densities of hops, the investigations included trials with fresh and dried hop samples. Clear differences were observed between hop varieties both in measured pressure drops and in bulk densities. Moreover, in the case of fresh hops, a non-linear increase in pressure drop with bed height was ascertained. Semi-empirical equations were developed to describe pressure drop as a function of air velocity. This work will contribute to the design of dryers with optimum airflow distribution and thus enhance the efficiency of drying as well as the product quality.

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2391–2409 H. Kaletnik, I. Sevostianov, V. Bulgakov, I. Holovach, V. Melnik, Ye. Ihnatiev and J. Olt,
Development and examination of high-performance fluidised-bed vibration drier for processing food production waste
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Development and examination of high-performance fluidised-bed vibration drier for processing food production waste

H. Kaletnik¹, I. Sevostianov¹, V. Bulgakov², I. Holovach², V. Melnik³, Ye. Ihnatiev⁴ and J. Olt⁵,*

¹ Vinnytsia National Agrarian University of Ukraine, 3 Soniachna Str., UA21008 Vinnytsia, Ukraine
² National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., UA03041 Kyiv, Ukraine
³ Kharkiv Petro Vasylenko National Technical University of Agriculture, 44 Alchevskih Str., Kharkiv, UA61002, Ukraine
⁴ Dmytro Motornyi Tavria State Agrotechnological University, 18B, Khmelnytsky Ave, UA72310 Melitopol, Zaporozhye Region,Ukraine
⁵ 5Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi Str., EE51006 Tartu, Estonia

Abstract:

Drying and processing wet particulate food production waste, such as distillery dreg, brewer’s grains, beet pulp, spent coffee and barley slurry etc. for their further use as cattle fodder or fuel is an important and topical problem, which needs effective solutions. As a solution of the problem, the authors have developed improved equipment and a fluidised bed vibration drier, which ensures reaching the required output of the work process and final moisture content in the waste at a minimum power and material intensity and features the combination of the high feasibility with the high reliability of design. In order to validate the improved drying work process together with the optimum parameters of the vibration drier, theoretical investigations based on the mathematical model of the process developed by the authors have been carried out. The process of the vibration drier’s frame oscillating together with the waste has been examined, which has resulted in the generation of the differential equation that analytically describes the said process. The work process under consideration has been researched into from the thermophysical point of view using the specific initial data typical for the specific food producer. The research has resulted in obtaining the following design and process parameters of the vibration drier, in particular, for its heating pipes: diameter rt = 0.1 m; length lt = 5 m; number nt = 20, heat-transfer factor Kp = 30 and the final temperature of the dried food production waste to2 = 80 °C. The listed parameters provide for reaching the required final moisture content in the dried food production waste. Also, new relations have been generated for determining the principal process parameters of the improved drier (productive capacity, heat consumption, mass of heat carrier, waste conveyance speed, sizes and masses of the drier’s actuating elements). The obtained relations can be applied in the further theoretical and experimental research on the drier as well as the development of standard methods for its design and calculation.

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2271-2284 O. Zavadska, І. Bobos, I. Fedosiy, G. Podpryatov and J. Olt
Studying the storage and processing quality of the carrot taproots (Daucus carota) of various hybrids
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Studying the storage and processing quality of the carrot taproots (Daucus carota) of various hybrids

O. Zavadska¹, І. Bobos¹, I. Fedosiy¹, G. Podpryatov¹ and J. Olt²*

¹National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., UA 03041 Kyiv,Ukraine
²Estonian University of Life Sciences, Institute of Technology, 56 F.R. Kreutzwaldi Str., 51006 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

This paper presents the results acquired from the study of eight carrot hybrids which are suitable for growing in the climatic zone of woodland steppes, while considering a set of economical and/or biological, biochemical, and organoleptic properties. The carrot hybrids that were studied have a wide range of variation in their economic value indicators, which makes it possible to grow them for storage and processing in various soils and climate conditions without irrigation. The most productive carrot hybrids are White Sabine F1 and Yellowstone F1 with a commercial yield of 55.8–58.7 t hа–1 and an average taproot weight of 118.7–136.2 g. The levels of preservation of the taproot of the hybrids White Sabine F1 and Purple Haze F1 after seven months of storage in conditions that involved the use of a stationary pit storage facility was at 81.4% and 80.2% respectively. The use of the taproots of the hybrids Yellowstone F1 and Viking F1 for drying ensures a yield of a high-quality, biologically-valuable finished product with a yield of 11.4–11.7%. Dry hybrid Evolyutsiya F1 and Mars F1 carrots contain more than 40 mg (100 g)–1 of β-carotene.

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2166-2184 J.L. Paes, B.C. Vargas, J.P.B. Cunha, D.S.C. Silva, G.A.S. Ferraz, M.R.S. Braz, P.F.P. Ferraz, L. Conti and G. Rossi
Thermal performance of a solar hybrid dryer for Conilon coffee (Coffea canephora)
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Thermal performance of a solar hybrid dryer for Conilon coffee (Coffea canephora)

J.L. Paes¹*, B.C. Vargas¹, J.P.B. Cunha¹, D.S.C. Silva¹, G.A.S. Ferraz², M.R.S. Braz¹, P.F.P. Ferraz², L. Conti³ and G. Rossi³

¹Rural Federal University of Rio de Janeiro, Engineering Department, Campus Seropédica, ZIP Code BR23890000, Seropédica, Rio de Janeiro, Brazil
²Federal University of Lavras, Agricultural Engineering Department, ZIP Code BR37200000, Lavras, Minas Gerais, Brazil
³University of Florence, Department of Agricultural, Food, Environment and Forestry (DAGRI), Via San Bonaventura, 13, IT50145, Florence, Italy *Correspondence: juliana.lobop@gmail.com

Abstract:

The study was aimed at design and development of an energy efficient hybrid solar dryer suitable for drying of organic Conilon coffee placed in the town of Seropédica, Rio de Janeiro, Brazil. The energy efficiency and the drying efficiency were the evaluation criteria for thermal performance of the hybrid solar dryer during the coffee drying. Temperature and relative humidity (RH) of the drying and ambient air, solar radiation intensity and coffee weight loss were monitored during the drying process. The process occurred over six consecutive days; the drying time was from 07:00 to 17:00 h, totalling 120 h of operation with an intermittent period (at night) of 14 h. During intermittence, the exhaust system kept off and solar collector and drying chamber sealed. The effective drying period took 60 h, with temperature and RH, respectively, of 38.3 °C and 60.6% outlet of the solar collector, 32.7 °C and 72.2% outlet drying chamber and 27.8 °C and 74.5% ambient air. The maximum temperature in the solar collector and drying chamber reached 54 and 47.7 °C, respectively, with an ambient air temperature of 32 °C at 12:00 h. These values showing temperature increase 22.2 °C in solar collector and 10 ºC drying chamber. The mean variation for the reduction in RH between the drying air inside the solar collector and the ambient air was 28%, while in the chamber obtained in a range of 10.5% at 13:00 h. The solar collector and dryer chamber efficiency were 29.1 and 40.8%, respectively, while the overall dryer efficiency 39.7%.

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360-375 V. Bulgakov, I. Holovach, S. Kiurchev, S. Pascuzzi, M. Arak, F. Santoro, A.S. Anifantis and J. Olt
The theory of vibrational wave movement in drying grain mixture
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The theory of vibrational wave movement in drying grain mixture

V. Bulgakov¹, I. Holovach¹, S. Kiurchev², S. Pascuzzi³, M. Arak⁴, F. Santoro³, A.S. Anifantis³ and J. Olt⁴*

¹National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., Kyiv UA 03041, Ukraine
²Dmytro Motornyi Tavria State Agrotechnological University, 18B Khmelnytsky Ave, UA 72310, Melitopol, Zaporozhye Region, Ukraine
³University of Bari Aldo Moro, Department of Agricultural and Environmental Science, Via Amendola, 165/A, IT70125 Bari, Italy
⁴Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi Str., EE51006 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

This paper outlines a theory that involves the vibrational wave transportation of bulk grain during the course of passing that grain under an infrared radiation source, in a working thermal radiation drying chamber, and using a vibrational wave transporter belt that has been developed by the authors of this paper. The main outstanding feature of the proposed design is the presence of mechanical off-centre vibration drives which generate the vibration in the working rollers at a preset amplitude and frequency, thereby generating a mechanical wave on the surface of the flexible transporter belt which ensures the movement of bulk grain along the processing zone which itself is being subjected to infrared radiation. A calculation method was developed for the oscillation system that is used in conjunction with the vibrational transportation of the grain mass, in order to be able to determine the forces that may be present in the vibrational system and to prepare the differential calculations for the movement of the vibrational drive’s actuators, utilising for this purpose Type II Lagrange equations. The solving of the aforementioned integral equations on a PC yielded a number of graphical dependencies in terms of kinetic and dynamic parameters for the vibrational system described above; the analysis of those dependencies provided a rational structural, along with kinetic and dynamic indicators. According to the results that were taken from theoretical and experimental studies on the functioning of the developed infrared grain dryer combined with a vibrational exciter, stable movement for its working roller takes place if the angular velocity of a drive shaft is changed within the range of between 50–80 rads–1, whereas the amplitude of the indicated oscillations falls within the range of 3.0–4.0 mm. It has been discovered that a rational speed when transporting soy seeds during infrared drying falls between the range of between 0.15–0.60 cm s-1, whereas the amplitude of the indicated oscillations falls within the range of 3.0–4.0 mm. An increase of this parameter within the stated limits increases the time that it takes to achieve the stage in which a constant drying soy speed is reached by more than 2.5 times (from 205 seconds to 520 seconds), stabilising the figure at a level of 520 seconds, which makes it possible to recommend a range of transport speeds of between 0.15–0.40 cm s–1 under infrared radiation for the seeds in order to achieve the required moisture content with a single pass of the produce on the wave transporter.
With that in mind, the power consumption levels for the vibrational exciter do not exceed 50W, while the angular velocity of the drive shaft’s rotation falls within the range of between 100–120 rads–1. The results of the experimental study that has been conducted indicated that a rational transportation speed for the soy seeds on the wave transporter under infrared radiation is between 0.15–0.40 cm s–1.

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1301-1311 A. Aboltins, T. Rubina and J. Palabinskis
Shrinkage effect on diffusion coefficient during carrot drying
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Shrinkage effect on diffusion coefficient during carrot drying

A. Aboltins¹, T. Rubina²* and J. Palabinskis¹

¹Latvia University of Life Sciences and Technologies, Faculty of Engineering, Institute of Agricultural Machinery, J.Cakstes Blv 5, LV-3001 Jelgava, Latvia
²Latvia University of Life Sciences and Technologies, Faculty of Information Technologies, Department of Computer Systems, Liela 2, LV-3001 Jelgava, Latvia
*Correspondence: tatjana.rubina@llu.lv

Abstract:

Many studies have been previously carried out on the carrot drying and the undergoing processes. The developed mathematical models provide an opportunity to gain an understanding of this complex process and its dynamics. But they are simplified and based on a number of assumptions, including calculation of diffusion coefficient values. In one of the previous studies, the authors of this study determined that the diffusion coefficient is linearly dependent on the moisture concentration with the assumption that the sample’s geometric shape does not change. The aim of this study is to determine the dependence of the diffusion coefficient on the moisture concentration taking into account the change in sample thickness during the drying experiment. The experiments were carried out with carrot slices of three different thicknesses: 5 mm, 10 mm and 15 mm thickness on the film infrared dryer at temperature 40 °C. During the experiments, measurements of the weight and thickness of the slices were performed. Using the experimental data the average thickness and diffusion coefficient of slices was calculated depending on the moisture concentration. Obtained results show that thickness depends linearly on the moisture concentration. Using experimental data and obtained average values of samples thickness, the values of diffusion coefficient was calculated. The results indicate that diffusion coefficient value depend linearly on moisture concentration. Their values are close and tend to zero when the concentration decreases if the thickness changes are taken into account during the experiment.

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723-727 P. Heřmánek, A. Rybka and I. Honzík
Determination of moisture ratio in parts of the hop cone during the drying process in belt dryer
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Determination of moisture ratio in parts of the hop cone during the drying process in belt dryer

P. Heřmánek*, A. Rybka and I. Honzík

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Agricultural Machines, Kamýcká 129, CZ165 00 Praha 6 - Suchdol, Czech Republic
*Correspondence: hermanek@tf.czu.cz

Abstract:

The paper deals with monitoring the moisture content of hop cones and their parts (strigs and bracts) in PCHB 750 hop belt dryer. When drying hop cones, the critical point is the sufficient drying of the strig. These are therefore dried to a moisture content of 6 to 8%. This exact moisture provides a sufficient guarantee ensuring that the strig is dried up. On the other hand, bracts are dried up to such a level which makes pressing the hops impossible. Therefore, after drying, the bracts are remoistened. This is called hops conditioning. After conditioning the moisture content of hops is optimal, ranging between 8 and 11%. There is no doubt that drying or any further moistening does not benefit the hop cone.
During the experiment, the moisture content was determined regarding the whole hop cones as well as the bracts and strigs separately, the samples of which had been taken from the hops prior to entering the dryer, from different parts of belts in the dryer and subsequently before and after the conditioning. The moisture content was determined by means of Mettler HE53 moisture analyzer. After the bracts and strigs had been dried, we calculated their weight ratio which was approx. 90% of bracts and 10% of strigs. Based on this ratio the weighted average was calculated which corresponds to the moisture content of the whole hop cone.
The measured values indicate that the average moisture content of hops below 10% was already at the beginning of the third belt of the dryer. The hops had been unnecessarily overdried along the whole third belt. Another output refers to the moisture ratio of hop cones, bracts and strigs in different parts of the dryer. The obtained values will serve as a basis for the follow-up design of a device for monitoring the dryer parameters and its visualisation.

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349-356 V. Bulgakov, V. Bandura, M. Arak and J. Olt
Intensification of rapeseed drying process through the use of infrared emitters
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Intensification of rapeseed drying process through the use of infrared emitters

V. Bulgakov¹, V. Bandura², M. Arak³ and J. Olt³*

¹National University of Life and Environmental Sciences of Ukraine, 15, Heroyiv Oborony street, UA03041 Kyiv, Ukraine
²Vinnytsia National Agrarian University of Ukraine, Soniachna street 3, UA21008 Vinnytsia, Ukraine
³Estonian University of Life Sciences, Kreutzwaldi 56, EE51014 Tartu, Estonia; *Correspondence: jyri.olt@emu.ee

Abstract:

The theoretical basis of the agricultural material drying techniques has been formed in the world for two and a half centuries. Nevertheless, despite the multitude of studies well presented in the literature, the industry still lacks universally recognized methods of design calculation for the majority of drying problems. Presumably, this is due to the fact that the dehydration of foodstuffs is one of the most energy-intensive and complicated work processes. In the process of thermal treatment during the drying, the physical state of the water in the treated item changes, the properties of the item itself are altered.
Recently, the drying of foodstuffs by means of infrared (IR) radiation has been gaining ever wider acceptance. At the same time, the technologies for dehydrating foodstuffs and materials are now far ahead of the theory of drying. Not only the classical literature on the drying problems, but even special studies on the subject cannot provide any specific recommendations for the design of installations with the electro-magnetic principle of energy input. Whereas that is exactly the type of installations that are now actively making headway, while offering serious challenges in their modelling. For that reason, experimenting has until now been the only reliable way of their studying. Despite the available extensive scientific literature on the drying, including works on IR units, the practical issues of engineering IR driers have not been tackled. All the existing studies consider solely particular cases. This study discusses the process of drying the fixed bed of rapeseeds with the use of the electromagnetic infrared emitter. The energy intensity of the process and the optimum thickness of the product bed are determined. The aim of the paper is to examine the effect that the operating condition parameters (energy input intensity, temperature, grain bed thickness) have on the drying kinetics and the energy characteristics of the process. The methods of research are based on the thermophysical analysis of the material’s structure. The experimental studies were carried out with the use of monitoring and measuring equipment, up-to-date methods and instruments, including solutions developed by the authors. The analytical treatment was performed with the use of the software packages: MathCAD, Excel. The sample testing and examination took place in the laboratory and the methods were in compliance with the applicable standards. A comprehensive experimental investigation of the effect that the operating parameters (specific load and power) have on the rape seed IR-drying kinetics had been accomplished.

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713–719 P. Heřmánek, A. Rybka and I. Honzík
Experimental chamber dryer for drying hops at low temperatures
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Experimental chamber dryer for drying hops at low temperatures

P. Heřmánek*, A. Rybka and I. Honzík

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Agricultural Machines, Kamýcká 129, CZ165 00 Praha 6 – Suchdol, Czech Republic
*Correspondence: hermanek@tf.czu.cz

Abstract:

Hop drying takes a significant part in growers’ costs of the final product processing. The current drying technology is based on drying at the drying air temperature of 55–60 °C for 6–9 hours to the final moisture content of about 10%. However, the process results in irreversible transformations and losses of, inter alia, heat labile substances contained in hops.
The experimental chamber dryer was tested at harvest in 2016. Assays hop drying were carried out at a temperature of the drying medium 40 °C. The research results in the form of an experimental new experimental chamber dryer will be used for testing of drying technologies at lower temperatures of the drying medium.
This is what will enable to preserve the quality of aroma as well as other characteristics of the components contained in hops.

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