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- 1. DESIGNED AND DEVELOPED UNDER THE AEGIS OF NAHEP Component-2 Project Investments In ICAR Leadership In Agricultural Higher Education Division of Computer Applications ICAR-Indian Agricultural Statistics Research Institute
- 2. Course Details Course Name Engineering Properties of Agricultural Produce Lesson 1. Classification of Engineering Properties of Agricultural Produce Disclaimer : Presentations are intended for educational purposes only and do not replace independent professional judgement. Statement of fact and opinions expressed are those of the presenter individually and are not the opinion or position of ICAR-IASRI. ICAR-IASRI does not endorse or approve, and assumes no responsibility for the content, accuracy or completeness of the information presented.
- 3. Name Role University Sangani Velji Premji Content Creator Junagadh Agricultural University, Junagadh Shahzad Faisal Course Reviewer Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar Created by
- 4. Objectives: 則 To classify engineering properties of agricultural produce 則 To give importance of engineering properties of agricultural produce
- 5. Glossary of terms: 則 Physical properties: A physical property is any property that is measurable, whose value describes a state of a physical system. 則 Thermal properties: Property of a solid body related to application of heat energy is defined as a. thermal property 則 Aerodynamic properties: A branch of dynamics that deals with the motion of air and other gaseous fluids and with the forces acting on bodies in motion relative to such fluids 則 Rheological properties: The action of forces results in deformation and flow in the material, the mechanical properties will be referred to as rheological properties.
- 6. 則 Mechanical Properties: Mechanical Properties may be defined as the behavior of the material under applied forces. 則 Frictional properties: Frictional property is the surface property of the solid materials when two solid surfaces slide against each other. 則 Electric properties: Properties of a substance which determine its response to an electric field, such as its dielectric constant or conductivity.
- 7. Introduction: 則 Agricultural produce especially that are consumed as food or feed undergo various unit operations right from the pre-harvest to post harvest 則 Post Harvest processing, i.e., primary, secondary and tertiary processing, formulation, preservation, packaging, storage distribution, retailing, domestic storage and finally consumption. 則 Scientists and engineers need to know and understand the characteristics of the material to be processed, preserved and consumed to solve the problems while designing and selecting the means and modes of preservation, packaging, processing, storage, marketing, and consumption. 則 Each of these unit operations has unique characteristics and need special tools and equipments.
- 8. 則 Designing and selecting such tools and equipments require information regarding various properties. 則 These properties are of great importance in the simulation and design of food processes and in the computer-aided process engineering. 則 Not only the knowledge of properties aids in engineering design and control but also gives information about the product quality, its acceptability by the consumers
- 9. Classification of food properties: 則 There are many classifications of properties of biological materials, which can generally be grouped under physical properties, mechanical properties, rheological properties, textural properties, electrical and dielectric properties, optical properties, acoustic properties, chemical, and nutritional properties etc.
- 10. Physical properties Size Shape Sphericty Roundness Volume Thousand grain weight Bulk density True density Porosity Surface area
- 11. Aerodynamic properties Terminal velocity Drag coefficient Thermal properties Thermal conductivity Specific heat Enthalpy Thermal diffusivity Latent heat Surface heat transfer coefficient Emissivity
- 12. Frictional properties Coefficient of friction Angle of repose Rolling resistance Mechanical properties Hardness Compressive strength Impact and shear resistance Firmness
- 13. Rheological properties Elasticity Viscoelasticity Viscoplasticity Plasticity Viscosity Electrical properties Electrical conductivity Electrical resistivity Dielectric properties Optical properties Colour Appearance Brightness
- 14. Importance of engineering properties of agricultural produce Physical properties: 則 The knowledge of some important physical properties such as shape, size, sphericity, volume, surface area, thousand grain weights, density, and porosity of different grains is necessary for the design of various separating, handling, storing and drying systems. 則 The size and shape are, for instance, important in their electrostatic separation from undesirable materials and in the development of sizing and grading machinery.
- 15. 則 Bulk density, true density, and porosity (the ratio of intergranular space to the total space occupied by the grain) can be useful in sizing grain hoppers and storage facilities. 則 It can also affect the rate of heat and mass transfer of moisture during aeration and drying processes. 則 Density is used to separate materials with different densities or specific gravities. 則 Separation of properly matured peas can be separated from the immature and infected ones by water flotation methods.
- 16. 則 Grain bed with low porosity will have greater resistance to water vapor escape during the drying process, which may lead to higher power to drive the aeration fans. 則 Cereal grain densities have been of interest in breakage susceptibility and hardness studies.
- 17. 則 Bulk density values for raw and parboiled paddy have practical applications in the calculation of thermal properties in heat transfer problems, in determining Reynolds number in the pneumatic handling of the material, and in separating the product from undesirable materials. 則 It plays an important role in other applications that include the design of silos and storage bins and the maturity and quality of paddy, which are essential to grain marketing.
- 18. 則 The resistance of bulk grain to airflow is in part a function of the porosity and the kernel size. 則 Knowledge of surface area of some parts of plant materials, such as leaf area and surface area of fruits is important to plant scientist as well as engineers handling and processing the products. 則 Surface areas of fruits are important in investigation related to spray coverage, removal of spray residues (washing), respiration rate, light reflectance and color evaluation, heat transfer studies in heating and cooling processes and wax coating of fruits and vegetables.
- 19. Aerodynamic properties: 則 The aerodynamic properties like terminal velocity and drag coefficient of agricultural products are important and required for the designing of air conveying systems and the separation equipment. 則 In the handling and processing of agricultural products, air is often used as a carrier for transport or for separating the desirable products from unwanted materials. 則 As the air velocity, greater than terminal velocity, lifts the particles to allow greater fall of a particle, the air velocity could be adjusted to a point just below the terminal velocity. 則 The fluidization velocity for granular material and settling velocity are also calculated for the body immersed in viscous fluid.
- 20. Thermal properties: 則 These properties are involved in almost every food processing operation. 則 Thermal properties are important for modeling processes (microwave heating, extrusion, freezing, etc.), engineering design of processing equipment, calculating energy demand, and development of sterilization and aseptic processing. 則 Thermal properties also affect sensory quality of foods as well as energy saving from processing. 則 It is strictly based on how much energy is needed not the rate at which it takes to raise the temperature.
- 21. 則 Specific heat has an important role in determination of energy cost and for the dimensions of machinery and equipment that are needed in thermal processes. 則 Specific heat (Cp) of food materials changes according to their physical and chemical properties. 則 The importance of thermal conductivity is to predict or control the heat flux in food during processing such as cooking, frying, freezing, sterilization, drying or pasteurization.
- 22. 則 The thermal conductivity (k) of food determines how fast heat can be evenly transferred to the entire food mass, which in turn affects the quality of the final product. 則 Thermal diffusivity determines how fast heat propagates or diffuses through a material. 則 It helps estimate processing time of canning, heating, cooling freezing, cooking or frying. 則 When heating and cooling of materials involves unsteady state or transient heat conduction, the material temperature changes with time and knowledge of the thermal diffusivity (留) is required for predicting temperature in these processes.
- 23. Frictional properties: 則 Frictional properties such as angle of repose and coefficient of friction are important in designing equipment for solid flow and storage structures and the angle of internal friction between seed and wall in the prediction of seed pressure on walls. 則 The coefficient of static friction plays also an important role in transports (load and unload) of goods and storage facilities. 則 It is important in filling flat storage facility when grain is not piled at a uniform bed depth but rather is peaked. 則 Coefficient of friction is important in designing storage bins, hoppers, chutes, screw conveyors, forage harvesters, and threshers.
- 24. 則 The material generally moves or slides in direct contact with trough, casing, and other components of the machine. The various parameters affect the power requirement to drive the machine. 則 The frictional losses are one of the factors, which must be overcome by providing additional power to the machine. Hence, the knowledge of coefficient of friction of the agricultural materials is necessary. 則 In some material handling applications, rolling resistance or maximum angle of stability in rolling of agricultural materials with rounded shapes may serve as useful design information.
- 25. Mechanical properties Hardness of grains has been a subject of interest to millers, livestock feeders, breeders and other agricultural scientists. Biting or cutting the grains has provided a quantitative evaluation of grain hardness. Mechanical properties such as compressive strength, impact and shear resistance are important and in some cases necessary engineering data in studying size reduction of cereal grains as well as seed resistance to cracking under harvesting and handling conditions.
- 26. 則 From energy stand point, this information can be used to determine the best method (shear, impact or static crushing) to breakup or grind grain. 則 Shearing resistance and bending strength of forage crops as they are cut are also important mechanical properties for understanding the nature of the cutting process and energy requirements in mowing machines and chaff cutter.
- 27. Rheological properties: 則 Knowledge of the rheological of various food systems is important in the design of flow processes for quality control, in predicting storage and stability measurements, and in understanding and designing texture. 則 The rheological behavior under limited deformation has been widely used to obtain information on the structure and viscoelasticity of materials.
- 28. 則 An understanding of flow behavior is necessary to determine the size of the pump and pipe and the energy requirements. 則 The rheological models obtained from the experimental measurements can be useful in design of food engineering processes if used together with momentum, energy, and mass balances. 則 Effects of processing on rheological properties must be known for process control.
- 29. Optical properties: 則 Light transmittance and reflectance properties of agricultural commodities are used for sorting, grading, maturity, surface colour and blemish determination. 則 The use of hyperspectral, multispectral, infrared imaging and computer vision system have enabled even determination of moisture and other chemical composition, contamination of agro commodities to greater satisfaction of consumer and trader and reduced the manual inspection. 則 These systems offer the potential to automate manual grading practices and thus to standardize techniques and eliminate tedious inspection tasks. 則 The automated inspection of produce using machine vision not only results in labour savings, but also can improve inspection, objectivity.
- 30. Electrical properties: 則 Some electrical properties which are of importance in agro processing are electrical conductance, resistance, impedance. 則 Electrical conductance or capacitance has been used for determining the moisture content of grain. 則 Electrostatic separation of grains is also used for separating grains, based on the ability of the grain to hold electrostatic charge.
- 31. 則 Electrical conductivity of the grain decides the ability of the material to hold electrostatic charge. 則 Recently ohmic heating has been in use for drying, pasteurization, blanching and other thermal processing of foods, based on resistance heating.
- 32. 則 Ohmic processing, sometimes described as resistive heating, consists of passing mains alternating current directly through a conductive food, which in turn leads to heat generation. 則 Because heating accompanies the current; heat distribution throughout the product is far more rapid and even, which in turn can result in better flavor retention and particulate integrity compared to conventional processes. 則 The efficiency of ohmic heating is dependent on the conductive nature of the food to be processed and hence knowledge of the conductivity of the food as a whole and its components is essential in designing a successful heating process.
- 33. Dielectric properties: 則 Dielectric properties play a major role in determining the interaction between the food material being processed and the electromagnetic energy. 則 The degree of heating of a food material subjected to microwave or radio frequency processing is strongly influenced by the dielectric properties of the food. 則 Dielectric heating or volumetric heating occurs due to polarization and ionization of molecules, which are effectively used in drying, sterilization, pasteurization and other thermal processing operations.
- 34. 則 Dielectric constant is a measure of the ability of a material to store electromagnetic energy whereas dielectric loss factor is a measure of the ability of a material to convert electromagnetic energy to heat. 則 Loss tangent (tan 隆), a parameter used to describe how well a product absorbs microwave energy, is the ratio of 竜 to 竜. 則 A product with a higher loss tangent will heat faster under microwave field as compared to a product with a lower loss tangent.
- 35. THANK YOU