Geometric and Mechanical Properties of Mung Bean (Vigna RadiataL.) Grain: Effect of Moisture

Abstract

In this research, selected geometric and mechanical properties of mung bean grain were evaluated as a function of moisture content. Five levels of moisture content ranging from 7.28 to 17.77% d.b. (dry basis) were used. The average length, width, thickness, arithmetic and geometric mean diameters, sphericity, thousand grain mass and angle of repose ranged from 5.145 to 6.199 mm, 3.760 to 4.474 mm, 3.537 to 4.223 mm, 4.147 to 4.965 mm, 4.090 to 4.893 mm, 0.795 to 0.789, 52.3 to 64.6 g, and 25.87 to 29.38° as the moisture content increased from 7.28 to 17.77% d.b., respectively. The bulk density was found to be decreased from 821.3 to 745.2 kg/m 3 , whereas the grain volume, true density, porosity, terminal velocity, and projected area were found to be increased from 27.88 to 47.33 mm 3 , 1230.0 to 1456.7 kg/m 3 , 30.43 to 46.57%, 4.86 to 5.29 m/s, and 17.48 to 19.26 mm 2 , respectively. There is a 43% increase in surface area from grain moisture content of 7.28 to 17.77% d.b. The static coefficient of friction on various surfaces increased linearly with the increase in moisture content. The rubber as a surface for sliding offered the maximum friction followed by galvanised iron, medium density fibreboard, stainless steel, aluminium and glass sheet. As moisture content increased from 7.28 to 17.77%, the rupture forces values ranged from 67.39 to 39.44 N; 63.86 to 42.18 N, and 53.96 to 41.79 N for thickness (Z axis), length (Y-axis) and width (X-axis), respectively.

Comparison of some physical and chemical characteristics of buckwheat (Fagopyrum esculentum Moench) grains

“…The arithmetic and geometric diameters were smaller than the length and greater than the width and thickness. Baümler, Cuniberti, Nolasco, and Riccobene (2006), Unal et al (2008), Ashtiani Araghi, Sadeghi, and Hemmat (2010), Gharibzahedi et al (2011), Ilori et al (2011 and Kaliniewicz et al (2015) found similar results for safflower, mung bean, rough rice, red lentil, Mexican sunflower and buckwheat seeds, respectively. The importance of these and other characteristic axial dimensions for determining aperture size and other parameters in machine design have been discussed by Mohsenin (1986).…”

“…This confirms the fact that the seeds are spherical or oval in shape, enabling the grains to roll. The measured angle of repose was considerably lower than that reported for rough rice (Ashtiani Araghi et al, 2010), mung bean (Unal et al, 2008) and lentil (Amin et al, 2004) and similar to that reported for buckwheat grain (Parde et al, 2003) and sorghum seed (Mwithiga & Sifuna, 2006). This may be due to the smoother surface or shape factor of buckwheat that imposes resistance to the seeds in sliding on one another.…”

“…The average true density was determined using the toluene displacement method. The volume of toluene displaced was found by immersing a weighed quantity of buckwheat seed in toluene (Mohsenin, 1986;Unal et al, 2008).…”

“…The reported value is the mean of 20 replications. The angle of repose was calculated from the following relationship (Amin et al, 2004;Unal et al, 2008):…”

“…Knowledge of the physical, chemical and nutritional properties of buckwheat grain are essential for the design of equipment for drying, cleaning, grading, storage and for the creation of value-added products. The importance of physical properties for designing post-harvest processing equipment has been emphasized earlier (Pradhan, Naik, Bhatnagar, & Vijay, 2009;Unal, Isık, Izli, & Tekin, 2008). In recent years, the physical, chemical and nutritional characteristics of various seeds such as buckwheat (Inglett, Rose, Chen, Stevenson, & Biswas, 2010;Kaliniewicz, Markowski, Anders, & Jadwisienczak, 2015;Kan, 2011;Parde, Johal, Jayas, & White, 2003;Steadman, Burgoon, Lewis, Edwardson, & Obendorf, 2001), flaxseed Coskuner & Karababa, 2007), vetch (Yalçın & Özarslan, 2004), lentil (Amin, Hossain, & Roy, 2004;Gharibzahedi, Ghasemlou, Razavi, Jafarii, & Faraji, 2011), sainfoin (Altuntas & Karadag, 2006), cowpea (Kabas, Yilmaz, Ozmerzi, & Akinci, 2007), wheat (Al-Mahasneh, Taha, & Rababah, 2007;Kalkan & Kara, 2011), chia (Ixtaina, Nolasco, & Tomás, 2008), mung bean (Unal et al, 2008), sorghum (Mwithiga & Sifuna, 2006), rapeseed (Unal, Sincik, & Izli, 2009) and sunflower (Ilori, Oradugba, & Raji, 2011) have been studied.…”