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The Influence of Grain Moisture Content on Specific Energy During Spring Wheat Grinding
Available online at www.sciencedirect.com
ScienceDirect Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
Farm Machinery and Processes Management in Sustainable Agriculture, 7th International Scientific Symposium
The influence of grain moisture content on specific energy during spring wheat grinding Zeyad Arif Ahmeda, Rafał Nadulskia *, Zbigniew Kobusa, Kazimierz Zawiślaka 0F
a
University of Life Sciences in Lublin, Department of Food Engineering and Machinery Doświadczalna 44, 20-236 Lublin, Poland
Abstract Grinding is the fundamental operation in the processing of cereal grain. From the viewpoint of the processing technology, the significant aspect is the energy intensity of the process. Apart from the equipment used, the process of grinding is affected by grain moisture and its mechanical properties that are determined primarily by the cultivar factor. The principal objective of the study was the determination of the effect of moisture content of kernels of new spring wheat cultivars on specific energy needed to crash them by a laboratory hammer mill. In all the cases an increase of kernel moisture causes an increase of the specific energy. The lowest specific energy during grinding, throughout the entire range of kernel moisture, was characteristic of cultivar Arabella, while the highest values of specific energy were obtained in the case of cultivar Mandaryna. The relationship of the specific energy to the kernel moisture content was described by means of linear equations.
© by Elsevier B.V. is anB.V. open access article under the CC BY-NC-ND license © 2015 2015 Published The Authors. Published by This Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Centre wallon de Recherches agronomiques (CRA-W). Peer-review under responsibility of the Centre wallon de Recherches agronomiques (CRA-W) Keywords: spring wheat; grindig; specific energy.
1. Introduction Knowledge of the mechanical properties of cereal grain is indispensable in the design of machines and technologies for the harvest, transport, storage, husking, grinding and flaking (Dziki et al. 2014, Andrejko et al. 2011, Laskowski et al. 2005). Grinding is the fundamental operation in the processing of cereal grain (Dziki 2008).
* Corresponding author. Tel.: +48 814610061 E-mail address: [email protected]
2210-7843 © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the Centre wallon de Recherches agronomiques (CRA-W) doi:10.1016/j.aaspro.2015.12.052
310
Zeyad Arif Ahmed et al. / Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
Mechanical grinders or mills for cereal grain are used both on individual farms and at large processing plants (Jasim and Ahmed 2012). Cereal grain grinding is performed primarily with the use of hammer mills and roller mills. From the viewpoint of the processing technology, the significant aspect is the energy intensity of the process. Apart from the equipment used, the process of grinding is affected by grain moisture and its mechanical properties that are determined primarily by the cultivar factor. An increase of grain moisture leads, as a rule, to increased energy requirements of the process, especially when decohesion of grain material is effected with the use of hammer mills (Dziki et al. 2011). Research by Dziki and Laskowski (2010) demonstrates that grain sprouting causes a significant increase of energy consumption for grinding. The process of grain grinding is also affected by its hardness. According to Dziki and Przypek-Ochab (2009) an increase of wheat grain hardness causes increased grinding energy consumption, the relation obtained being of a linear character. Kilborn et al. (1982) demonstrated that specific energy in the process of grinding of wheat grain amounts to from 46 kJ·kg-1 for common wheat cultivars to 124 kJ·kg-1 for durum wheat cultivars. Energy consumption depends significantly on the degree of comminution of the material. An increase of the degree of comminution causes an increase in the energy requirements of the grinding process, the relationship being most frequently described by an exponential equation (Laskowski et al. 2005). The principal objective of the study was the determination of the effect of moisture content of kernels of new spring wheat cultivars on specific energy needed to crash them by a laboratory hammer mill. 2. Material and Methods The investigations were conducted on four Polish wheat cultivars: Arabella, Kandella, Mandaryna and Struna, harvested in 2014, acquired from the plant breeding station DANKO Hodowla Roślin Sp. z o.o. in Chorynia. Those are new cultivars, registered in the Polish Register of Cultivars in the years 2011-2014. Arabella has very good quality parameters (group E/A). Cultivars from groups E (elite), A (very good) and B (good) are suitable for baking bread. It is a very early cultivar, characterised by very high yield levels over the entire territory of Poland. It is suitable for cultivation on poorer soils. It is characterised by high protein and gluten content. Kandela is characterised by very good quality grain (group A). Its yields are stable all over Poland. It tolerates slight acidification of soil, which permits its cultivation on soils with non-regulated pH. It is characterised by high protein and gluten content. Mandaryna has very good quality parameters (group A). It is characterised by very good productivity over the whole territory of Poland. It is an early cultivar with very good resistance to lodging. Struna has very good grain quality parameters. It is characterised by very high yields. It displays excellent adaptability to various soil and climate conditions. It is characterised by high content of protein and gluten. All of the cultivars included in the study are characterised by good or high resistance to diseases. The material was divided into kernel size classes using a Retsch As 200 sifter (VERDER Group, Holland), and then material of uniform size (>2mm) was taken for the analyses. In this study, five levels of moisture content of wheat kernels were determined: 10%, 12%, 14%, 16%, 18%. In order to reach these levels, the grain was conditioned by adding specific amounts of distilled water and mixed several times to ensure good distribution of added water for all kernels. The damped grains were isolated in separated containers for 3 days under normal laboratory temperature of 24±2oC. The grain was ground using a hammer mill of the type POLYMIX-Micro-Hammermill MFC (Glen Mills Inc., USA). The mill worked in conjunction with a computer system recording the power consumption. The mill was equipped with a replaceable screen with mesh size of 2.0 mm. The parameters determined in the tests were the specific energy of grinding and the ratio of the specific energy to the mass of grain ground. The test results were subjected to statistical analysis using one-factor analysis of variance ANOVA. The significance of differences was verified using the Fisher LSD test. 3. Results and Conclusion The tests demonstrated that the specific energy during the grinding of grain of the wheat cultivars under study varied from 52.9 kJKg-1 to 100.8 kJKg-1 in the case of cultivar Arabella, from 81.2 kJKg-1 to 124.1 kJKg-1 in the case of cultivar Kandela, from 77.8 kJKg-1 to 138.9 kJKg-1 in the case of cultivar Mandaryna, and from 64.4 kJKg-1 to 134.0 kJKg-1 in the case of cultivar Struna. The changes in the values of specific energy in relation to kernel moisture are presented in Fig. 2.
311
160
160
140
140
Specific energy Ej [kJ kg-1 ]
Specific energy Ej [kJ kg-1 ]
Zeyad Arif Ahmed et al. / Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
120 100 80 60 40 Arabella
20 0
120 100 80 60 40 Kandela
20 0
10
11
12
13
14
15
16
17
18
10
11
160
160
140
140
120 100 80 60 40 Mandaryna
20
13
14
15
16
17
18
17
18
Moisture content w [%]
Specific energy Ej [kJ kg-1 ]
Specific energy Ej [kJ kg-1 ]
Moisture cotent w [%]
12
0
120 100 80 60 40 Struna
20 0
10
11
12
13
14
15
16
17
18
10
Moisture content w [%]
11
12
13
14
15
16
Moisture content w [%]
Fig. 1. Effect of kernel moisture content w on specific energy Ej in the case of the wheat cultivars under study
Analysis of the graph shows that in all the cases an increase of kernel moisture causes an increase of the specific energy. The lowest specific energy during grinding, throughout the entire range of kernel moisture, was characteristic of cultivar Arabella, while the highest values of specific energy were obtained in the case of cultivar Mandaryna. Within the kernel moisture range under study the highest increase of specific energy was noted in the case of cultivars Struna - by 108.1% and Arabella - by 90.1%, while the smallest increase was obtained in the case of cultivars Kandela - by 52.8% and Mandaryna – by 78.7%. The relationship of the specific energy to the kernel moisture content was described by means of linear equations (Table 1). Table 1. Equations describing the relation between specific energy Ej and kernel moisture w Cultivar
Equation
R2
Arabell
Ej = 5.69w + 0.81
0.93
Kandela
Ej = 4.36w + 45.82
0.82
Mandaryna
Ej = 7.79w + 5.94
0.92
Struna
Ej = 7.9w + 19,93
0.89
The study indicates that, taking into account only the aspect of energy consumption, it is possible to select cultivars with low specific energy during grinding for cultivation and processing, which in effect will cause a reduction of production costs. The next stage of the study will be focused on research concerning the relations between selected strength properties of kernels and their susceptibility to grinding.
312
Zeyad Arif Ahmed et al. / Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
References Andrejko, D., Grochowicz, J., Goździewska, M., Kobus Z. 2011. Influence of infrared treatment on mechanical strength and structure of wheat grains. Food Bioproc. Tech. 4(8), pp. 1367-1375 Dziki, D. 2008. The crushing of wheat kernels and its consequence on the grinding process. Powder Technol. 185(2), pp. 181-186 Dziki, D., Cacak-Pietrzak, G., Miś, A., Jończyk, K., Gawlik-Dziki, U. 2014. Influence of wheat kernel physical properties on the pulverizing process. J. Food Sci. Technol. 51(10), pp. 2648-2655 Dziki, D., Laskowski, J. 2010. Study to analyze the influence of sprouting of the wheat grain on the grinding process. J. Food. Eng. 96(4), pp. 562-567 Dziki, D., Laskowski, J., Biernacka, B., Siastała, M. 2011. Wpływ wilgotności na proces rozdrabniania ziarna pszenicy zróżnicowanego pod względem twardości. Inżynieria Rolnicza, 1(126), pp. 47-53, (in polish) Dziki, D., Przypek-Ochab, D. (2009). Ocena energochłonności rozdrabniania ziarna pszenicy zróżnicowanego pod względem twardości. Inżynieria Rolnicza, 5(114),pp. 61-67 (in polish) Jasim, A. R. A.,, Ahmed, Z. A. 2012. The Effect of Some Mechanical Parameters on the Performance of MILL BUHLER AG 200 TON, The Iraqi Journal of Agricultural Science. 43(6), pp. 97-103 Kilborn, R.H., Black, H. C., Dexter, J. E., Martin D. G. 1982. Energy consumption during flour milling. Description of two measuring systems and influence of wheat hardness on energy requirements. Cereal Chem. 59, pp. 284-288. Laskowski, J., Łysiak, G., Skonecki, S. 2005. Mechanical properties of granular agro-materials and food powders for industrial practice. Part II. Material properties for grinding and agglomeration. Institute of Agrophysics PAS, Lublin, pp. 29-30
ScienceDirect Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
Farm Machinery and Processes Management in Sustainable Agriculture, 7th International Scientific Symposium
The influence of grain moisture content on specific energy during spring wheat grinding Zeyad Arif Ahmeda, Rafał Nadulskia *, Zbigniew Kobusa, Kazimierz Zawiślaka 0F
a
University of Life Sciences in Lublin, Department of Food Engineering and Machinery Doświadczalna 44, 20-236 Lublin, Poland
Abstract Grinding is the fundamental operation in the processing of cereal grain. From the viewpoint of the processing technology, the significant aspect is the energy intensity of the process. Apart from the equipment used, the process of grinding is affected by grain moisture and its mechanical properties that are determined primarily by the cultivar factor. The principal objective of the study was the determination of the effect of moisture content of kernels of new spring wheat cultivars on specific energy needed to crash them by a laboratory hammer mill. In all the cases an increase of kernel moisture causes an increase of the specific energy. The lowest specific energy during grinding, throughout the entire range of kernel moisture, was characteristic of cultivar Arabella, while the highest values of specific energy were obtained in the case of cultivar Mandaryna. The relationship of the specific energy to the kernel moisture content was described by means of linear equations.
© by Elsevier B.V. is anB.V. open access article under the CC BY-NC-ND license © 2015 2015 Published The Authors. Published by This Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Centre wallon de Recherches agronomiques (CRA-W). Peer-review under responsibility of the Centre wallon de Recherches agronomiques (CRA-W) Keywords: spring wheat; grindig; specific energy.
1. Introduction Knowledge of the mechanical properties of cereal grain is indispensable in the design of machines and technologies for the harvest, transport, storage, husking, grinding and flaking (Dziki et al. 2014, Andrejko et al. 2011, Laskowski et al. 2005). Grinding is the fundamental operation in the processing of cereal grain (Dziki 2008).
* Corresponding author. Tel.: +48 814610061 E-mail address: [email protected]
2210-7843 © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the Centre wallon de Recherches agronomiques (CRA-W) doi:10.1016/j.aaspro.2015.12.052
310
Zeyad Arif Ahmed et al. / Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
Mechanical grinders or mills for cereal grain are used both on individual farms and at large processing plants (Jasim and Ahmed 2012). Cereal grain grinding is performed primarily with the use of hammer mills and roller mills. From the viewpoint of the processing technology, the significant aspect is the energy intensity of the process. Apart from the equipment used, the process of grinding is affected by grain moisture and its mechanical properties that are determined primarily by the cultivar factor. An increase of grain moisture leads, as a rule, to increased energy requirements of the process, especially when decohesion of grain material is effected with the use of hammer mills (Dziki et al. 2011). Research by Dziki and Laskowski (2010) demonstrates that grain sprouting causes a significant increase of energy consumption for grinding. The process of grain grinding is also affected by its hardness. According to Dziki and Przypek-Ochab (2009) an increase of wheat grain hardness causes increased grinding energy consumption, the relation obtained being of a linear character. Kilborn et al. (1982) demonstrated that specific energy in the process of grinding of wheat grain amounts to from 46 kJ·kg-1 for common wheat cultivars to 124 kJ·kg-1 for durum wheat cultivars. Energy consumption depends significantly on the degree of comminution of the material. An increase of the degree of comminution causes an increase in the energy requirements of the grinding process, the relationship being most frequently described by an exponential equation (Laskowski et al. 2005). The principal objective of the study was the determination of the effect of moisture content of kernels of new spring wheat cultivars on specific energy needed to crash them by a laboratory hammer mill. 2. Material and Methods The investigations were conducted on four Polish wheat cultivars: Arabella, Kandella, Mandaryna and Struna, harvested in 2014, acquired from the plant breeding station DANKO Hodowla Roślin Sp. z o.o. in Chorynia. Those are new cultivars, registered in the Polish Register of Cultivars in the years 2011-2014. Arabella has very good quality parameters (group E/A). Cultivars from groups E (elite), A (very good) and B (good) are suitable for baking bread. It is a very early cultivar, characterised by very high yield levels over the entire territory of Poland. It is suitable for cultivation on poorer soils. It is characterised by high protein and gluten content. Kandela is characterised by very good quality grain (group A). Its yields are stable all over Poland. It tolerates slight acidification of soil, which permits its cultivation on soils with non-regulated pH. It is characterised by high protein and gluten content. Mandaryna has very good quality parameters (group A). It is characterised by very good productivity over the whole territory of Poland. It is an early cultivar with very good resistance to lodging. Struna has very good grain quality parameters. It is characterised by very high yields. It displays excellent adaptability to various soil and climate conditions. It is characterised by high content of protein and gluten. All of the cultivars included in the study are characterised by good or high resistance to diseases. The material was divided into kernel size classes using a Retsch As 200 sifter (VERDER Group, Holland), and then material of uniform size (>2mm) was taken for the analyses. In this study, five levels of moisture content of wheat kernels were determined: 10%, 12%, 14%, 16%, 18%. In order to reach these levels, the grain was conditioned by adding specific amounts of distilled water and mixed several times to ensure good distribution of added water for all kernels. The damped grains were isolated in separated containers for 3 days under normal laboratory temperature of 24±2oC. The grain was ground using a hammer mill of the type POLYMIX-Micro-Hammermill MFC (Glen Mills Inc., USA). The mill worked in conjunction with a computer system recording the power consumption. The mill was equipped with a replaceable screen with mesh size of 2.0 mm. The parameters determined in the tests were the specific energy of grinding and the ratio of the specific energy to the mass of grain ground. The test results were subjected to statistical analysis using one-factor analysis of variance ANOVA. The significance of differences was verified using the Fisher LSD test. 3. Results and Conclusion The tests demonstrated that the specific energy during the grinding of grain of the wheat cultivars under study varied from 52.9 kJKg-1 to 100.8 kJKg-1 in the case of cultivar Arabella, from 81.2 kJKg-1 to 124.1 kJKg-1 in the case of cultivar Kandela, from 77.8 kJKg-1 to 138.9 kJKg-1 in the case of cultivar Mandaryna, and from 64.4 kJKg-1 to 134.0 kJKg-1 in the case of cultivar Struna. The changes in the values of specific energy in relation to kernel moisture are presented in Fig. 2.
311
160
160
140
140
Specific energy Ej [kJ kg-1 ]
Specific energy Ej [kJ kg-1 ]
Zeyad Arif Ahmed et al. / Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
120 100 80 60 40 Arabella
20 0
120 100 80 60 40 Kandela
20 0
10
11
12
13
14
15
16
17
18
10
11
160
160
140
140
120 100 80 60 40 Mandaryna
20
13
14
15
16
17
18
17
18
Moisture content w [%]
Specific energy Ej [kJ kg-1 ]
Specific energy Ej [kJ kg-1 ]
Moisture cotent w [%]
12
0
120 100 80 60 40 Struna
20 0
10
11
12
13
14
15
16
17
18
10
Moisture content w [%]
11
12
13
14
15
16
Moisture content w [%]
Fig. 1. Effect of kernel moisture content w on specific energy Ej in the case of the wheat cultivars under study
Analysis of the graph shows that in all the cases an increase of kernel moisture causes an increase of the specific energy. The lowest specific energy during grinding, throughout the entire range of kernel moisture, was characteristic of cultivar Arabella, while the highest values of specific energy were obtained in the case of cultivar Mandaryna. Within the kernel moisture range under study the highest increase of specific energy was noted in the case of cultivars Struna - by 108.1% and Arabella - by 90.1%, while the smallest increase was obtained in the case of cultivars Kandela - by 52.8% and Mandaryna – by 78.7%. The relationship of the specific energy to the kernel moisture content was described by means of linear equations (Table 1). Table 1. Equations describing the relation between specific energy Ej and kernel moisture w Cultivar
Equation
R2
Arabell
Ej = 5.69w + 0.81
0.93
Kandela
Ej = 4.36w + 45.82
0.82
Mandaryna
Ej = 7.79w + 5.94
0.92
Struna
Ej = 7.9w + 19,93
0.89
The study indicates that, taking into account only the aspect of energy consumption, it is possible to select cultivars with low specific energy during grinding for cultivation and processing, which in effect will cause a reduction of production costs. The next stage of the study will be focused on research concerning the relations between selected strength properties of kernels and their susceptibility to grinding.
312
Zeyad Arif Ahmed et al. / Agriculture and Agricultural Science Procedia 7 (2015) 309 – 312
References Andrejko, D., Grochowicz, J., Goździewska, M., Kobus Z. 2011. Influence of infrared treatment on mechanical strength and structure of wheat grains. Food Bioproc. Tech. 4(8), pp. 1367-1375 Dziki, D. 2008. The crushing of wheat kernels and its consequence on the grinding process. Powder Technol. 185(2), pp. 181-186 Dziki, D., Cacak-Pietrzak, G., Miś, A., Jończyk, K., Gawlik-Dziki, U. 2014. Influence of wheat kernel physical properties on the pulverizing process. J. Food Sci. Technol. 51(10), pp. 2648-2655 Dziki, D., Laskowski, J. 2010. Study to analyze the influence of sprouting of the wheat grain on the grinding process. J. Food. Eng. 96(4), pp. 562-567 Dziki, D., Laskowski, J., Biernacka, B., Siastała, M. 2011. Wpływ wilgotności na proces rozdrabniania ziarna pszenicy zróżnicowanego pod względem twardości. Inżynieria Rolnicza, 1(126), pp. 47-53, (in polish) Dziki, D., Przypek-Ochab, D. (2009). Ocena energochłonności rozdrabniania ziarna pszenicy zróżnicowanego pod względem twardości. Inżynieria Rolnicza, 5(114),pp. 61-67 (in polish) Jasim, A. R. A.,, Ahmed, Z. A. 2012. The Effect of Some Mechanical Parameters on the Performance of MILL BUHLER AG 200 TON, The Iraqi Journal of Agricultural Science. 43(6), pp. 97-103 Kilborn, R.H., Black, H. C., Dexter, J. E., Martin D. G. 1982. Energy consumption during flour milling. Description of two measuring systems and influence of wheat hardness on energy requirements. Cereal Chem. 59, pp. 284-288. Laskowski, J., Łysiak, G., Skonecki, S. 2005. Mechanical properties of granular agro-materials and food powders for industrial practice. Part II. Material properties for grinding and agglomeration. Institute of Agrophysics PAS, Lublin, pp. 29-30