Unit Operations in Food Engineering MCQs 50 Score: 0 Attempted: 0/50 Subscribe 1. : Which of the following is a unit operation? (A) Fermentation (B) Filtration (C) Enzymatic reaction (D) Oxidation 2. : Heat transfer in conduction occurs due to: (A) Movement of fluids (B) Molecular interaction (C) Radiation (D) None of these 3. : The drying of food is primarily aimed at: (A) Improving taste (B) Increasing weight (C) Removing moisture (D) Adding flavor 4. : The process of separating suspended solids from liquids by gravity is called: (A) Filtration (B) Sedimentation (C) Evaporation (D) Centrifugation 5. : Which device is used to measure fluid flow rate? (A) Manometer (B) Thermometer (C) Orifice meter (D) Barometer 6. : In heat exchangers, the flow of fluids may be: (A) Co-current (B) Counter-current (C) Cross flow (D) All of the above 7. : The SI unit of thermal conductivity is: (A) W/mĀ·K (B) J/kgĀ·K (C) cal/gĀ·K (D) kJ/kg 8. : Evaporation is used in food processing mainly to: (A) Concentrate liquids (B) Remove gases (C) Increase viscosity (D) Add flavor 9. : The Reynolds number helps to determine: (A) Heat capacity (B) Flow regime (C) Thermal conductivity (D) Density 10. : The law governing steady-state heat conduction is: (A) Newtonās Law (B) Fourierās Law (C) Fickās Law (D) Daltonās Law 11. : Centrifugation separates particles based on differences in: (A) Color (B) Density (C) Texture (D) Shape 12. : The function of a cyclone separator is to: (A) Filter gases (B) Separate solids from air (C) Mix liquids (D) Cool gases 13. : The process of converting liquid into vapor at constant temperature is called: (A) Condensation (B) Evaporation (C) Sublimation (D) Adsorption 14. : Pasteurization is an example of: (A) Mechanical operation (B) Thermal operation (C) Chemical operation (D) Biological operation 15. : Which of the following is a non-mechanical separation process? (A) Sedimentation (B) Centrifugation (C) Filtration (D) Osmosis 16. : Spray drying is mainly used for producing: (A) Juices (B) Powders (C) Syrups (D) Gels 17. : The efficiency of a heat exchanger depends on: (A) Material color (B) Temperature difference (C) Humidity (D) Pressure only 18. : The process of converting liquid fat into solid is called: (A) Hydrogenation (B) Crystallization (C) Condensation (D) Solidification 19. : The main objective of blanching is to: (A) Inactivate enzymes (B) Cook the food (C) Sterilize completely (D) Remove fats 20. : The equipment used for size reduction of solids is: (A) Dryer (B) Grinder (C) Mixer (D) Heat exchanger 21. : Thermal diffusivity is the ratio of: (A) Conductivity to specific heat (B) Conductivity to density and specific heat (C) Temperature to mass (D) Energy to time 22. : Which drying method uses microwaves? (A) Freeze drying (B) Spray drying (C) Vacuum drying (D) Microwave drying 23. : In distillation, separation is based on differences in: (A) Density (B) Boiling point (C) Particle size (D) Color 24. : The process used to remove dissolved gases from liquids is called: (A) Evaporation (B) Deaeration (C) Filtration (D) Clarification 25. : The overall heat transfer coefficient is affected by: (A) Flow rate (B) Surface area (C) Type of material (D) All of the above 26. : In food engineering, āunit operationā refers to: (A) A complete process (B) A single physical step (C) A chemical reaction (D) Packaging process 27. : The specific heat of water is approximately: (A) 1.0 kcal/kg°C (B) 2.0 kcal/kg°C (C) 4.0 kcal/kg°C (D) 0.5 kcal/kg°C 28. : The process of removing water from vapor is called: (A) Condensation (B) Evaporation (C) Filtration (D) Distillation 29. : Homogenization is mainly used to: (A) Increase flavor (B) Reduce particle size (C) Increase color (D) Remove gases 30. : Which of the following is used for concentration of fruit juice? (A) Centrifuge (B) Evaporator (C) Homogenizer (D) Filter press 31. : Freezing point depression depends on: (A) Solute concentration (B) Pressure (C) Volume (D) Color 32. : Fickās law is related to: (A) Heat conduction (B) Diffusion (C) Pressure (D) Flow 33. : Which type of dryer uses direct contact with hot air? (A) Freeze dryer (B) Tray dryer (C) Vacuum dryer (D) Tunnel dryer 34. : The process of converting a solid directly into vapor is: (A) Melting (B) Evaporation (C) Sublimation (D) Condensation 35. : The thermal conductivity of metals is generally: (A) Low (B) High (C) Moderate (D) Constant 36. : Which equipment is used for mixing viscous food materials? (A) Ribbon blender (B) Hammer mill (C) Tray dryer (D) Filter press 37. : The viscosity of liquids generally: (A) Increases with temperature (B) Decreases with temperature (C) Remains constant (D) Depends on pressure only 38. : The principle of a plate heat exchanger is: (A) Direct heating (B) Indirect heat transfer (C) Mixing of fluids (D) Radiation 39. : The main purpose of filtration in food processing is to: (A) Add flavor (B) Remove suspended particles (C) Reduce viscosity (D) Pasteurize 40. : The major factor affecting drying rate is: (A) Temperature and humidity (B) Food color (C) Packaging (D) Solubility 41. : The process used to separate cream from milk is: (A) Filtration (B) Sedimentation (C) Centrifugation (D) Evaporation 42. : The heat required to convert liquid into vapor is called: (A) Latent heat (B) Sensible heat (C) Specific heat (D) Thermal conductivity 43. : In filtration, the resistance to flow increases with: (A) Pressure (B) Temperature (C) Cake thickness (D) Filtrate clarity 44. : Thermal death time refers to: (A) Time to freeze food (B) Time to sterilize microorganisms (C) Cooling period (D) Mixing time 45. : A pump is used in food processing to: (A) Move fluids (B) Filter solids (C) Reduce viscosity (D) Mix powders 46. : The main mode of heat transfer in a vacuum dryer is: (A) Conduction (B) Convection (C) Radiation (D) Both conduction and radiation 47. : Moisture content on a wet basis is calculated as: (A) (Moisture / Dry solids) Ć 100 (B) (Moisture / Total weight) Ć 100 (C) (Dry solids / Moisture) Ć 100 (D) (Total weight / Moisture) Ć 100 48. : The removal of volatile components by heating is called: (A) Distillation (B) Absorption (C) Filtration (D) Freezing 49. : Which factor influences viscosity the most? (A) Temperature (B) Color (C) Surface tension (D) Density 50. : Which operation involves both heat and mass transfer simultaneously? (A) Drying (B) Filtration (C) Mixing (D) Grinding