Volume 3 • Issue 8 • 1000175 J Food Process Technol ISSN:2157-7110 JFPT, an open access journal Open Access Research Article Food Processing & Technology Ghadge and Prasad, J Food Process Technol 2012, 3:8 http://dx.doi.org/10.4172/2157-7110.1000175 Keywords: Rice (Oryza sativa L.); Physical properties; Porosity; Bulk density; Static friction Notation: L: Lenth of seed (mm); W: Width of seed (mm); T: hickness of seed (mm); M: Unit mass; V: Volume; D 4 : Geometric mean dimension (mm); S p : Sphericity (%); S α : Surface area (mm 2 ); R α : Aspect ratio (%); ρ b : Bulk density (g/ml); ρ t : True density (g/ml); ε: Porosity (%); ϕ: Angle of repose (degrees); H: Height of the heap (mm); D: Diameter of the heap (mm); µ: Static coeicient of friction Introduction Rice (Oryza sativa L.) is one of the most important cereals cultivated worldwide, constituting the basic food for large number of human beings, sustaining two-thirds of the world population [1]. According to FAOSTAT, 2008, India accounts second in the production of rice ater China with total production of 141 MT and 187 MT respectively. However, the area under cultivation of the rice is about 44,000,000 hectares and 29,495,000 hectares in India and China respectively. he yield of rice is 32,075 hectogram per hectare and 80,538 hectogram per hectare respectively. his shows lower yield of rice in India, which could be increased by using high yielding varieties. Archaeological evidence indicates that rice was a part of the Indian diet by 8000 BC [2]. Agricultural activity during the second millennium BC included rice cultivation in the Kashmir and Harrappan regions [3]. In India, rice consumption is generally accomplished in various forms like whole cooked grain, as dish meal, where rice is served normally in two ways, white rice and parboiled grains. It is the main base for preparation of many indigenous fermented food products (like idli, dosa, uttapam, sake-an alcoholic beverage), sweets (anarasa, khir), khichadi, pulav, pufed and extruded products. he marketing values of rice as an agricultural product depend on its physical qualities ater the harvesting. he percentage of whole grain is the most important parameter for the rice processing industry (Marchezan, 1991)[4]. Broken grain has half the market value of head rice (head rice=75-100% of whole kernel) (Trop Rice International Rice Research Institute, 2004). As enlisted above, the machinery and operations when improperly designed may generate rice kernel cracking and breakage and consequently a low marketing price. he knowledge of the physical properties of the agricultural products is of fundamental importance during the harvesting of grains, transporting, design and dimensioning of correct storage procedure, manufacturing and operating diferent equipments used in post harvesting main processing operations of these products. he information related to porosity and speciic gravity, within other physical characteristics of the agricultural products, are of paramount importance for studies involving heat and mass transfer and air movement through the bulk grain. In addition, together with moisture content, volume, speciic gravity and porosity are the basic parameters for studying the drying and storage of agricultural products and to preview the quality loss of the material until its marketing time. he speciic gravity could be deined as the ratio between the mass of a body and its volume. his concept applied to the individual grain, it determines the real speciic gravity of the individual grain. When this concept is applied to the bulk grain determines the bulk density. According to Mohsenin [5], porosity is deined as the ratio of the inter-granular void space volume and the volume of the bulk grain. he porosity can be determined through the direct method by measuring the added liquid to fulill the void space of bulk grain. Several authors, through the years, pointed out the need for knowledge of other physical properties. For example, the static and dynamic friction coeicients, such as grains on the equipment wall and on the silo wall surfaces are necessaries and fundamentals for a rational and safe design of grain moving equipment, processing and storage [5-9]. his property develops an important role on silo wall pressure and grain lowing behaviors. he friction coeicient is deined as the ratio between the friction forces (force due to the resistance of movement) and the normal force on surface of the material used in the wall. For biological products, according to Mohsenin [5], two types of friction coeicients are considered, the static coeicient determined by the force capable to initiate the movement and the dynamic coeicient determined by the force needed to maintain the movement of the *Corresponding author: Prashant N. Ghadge, Department of Food Engineering, MGM College of Food Technology, Aurangabad – 431003 (M.S.) India, E-mail: pnghadge20@rediffmail.com Received December 19, 2011; Accepted July 05, 2012; Published July 11, 2012 Citation: Ghadge PN, Prasad K (2012) Some Physical Properties of Rice Kernels: Variety PR-106. J Food Process Technol 3:175. doi:10.4172/2157-7110.1000175 Copyright: © 2012 Ghadge PN, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract The objective of this work was to determine some of the physical properties of PR-106 type of rice variety which may inluence the rice processing operations. The physical properties Length or Longitudinal (L), Width (W), Thickness (T), Mass (M) and Volume (V) were measured at a moisture content of 13.34 ± 0.53% (dry basis) and the following results were obtained: the average split length, width, thickness, unit mass and volume were 6.61 mm, 1.75 mm, 1.40 mm, 0.017 g, and 0.051 cm 3 respectively. The calculated physical properties like the geometric mean diameter, surface area, porosity, sphericity, true density and aspect ratio were 2.52 mm, 20.10 mm 2 , 47.07%, 38.28%, 1.521 g/ml and 26.58% respectively. The static coeficient of friction varied on three different surfaces from 0.217 on galvanized steel sheet, 0.239 on Plywood to 0.249 on glass with splits perpendicular to direction of motion, while the angle of repose was 34.86°. Some Physical Properties of Rice Kernels: Variety PR-106 Prashant N. Ghadge 1 * and K. Prasad 2 1 Department of Food Engineering, MGM College of Food Technology, Aurangabad – 431003 (M.S.) India 2 Sant Longowal Institute of Engineering & Technology, Longowal – 148106 (Punjab) India