FDSC 241 Lecture 7 PDF

FDSC 241 Lecture 7 1. What is the transfer of heat via electromagnetic waves? - Radiation 2. What is the transfer of heat via direct contact between two different bodies? - Conduction 3. What is the transfer of heat via movement of molecules? - Convection 4...

FDSC 241 Lecture 7 1. What is the transfer of heat via electromagnetic waves? - Radiation 2. What is the transfer of heat via direct contact between two different bodies? - Conduction 3. What is the transfer of heat via movement of molecules? - Convection 4. Time to freeze is based on ______ and shape. - Dimension 5. Time to freeze is based on ______ change. - Enthalpy 6. Time to freeze is based on heat _______ of food material - Conductivit 7. Time to freeze is based on _____ and -_____ temperature of a product - Start, end 8. Time to freeze is based on heat transfer _________ - Coefficient 9. Time to freeze is based on temperature of _____ or cooling body - Coolant 10. Heat transfer coefficient is influenced by food _______ structure, food ___________, moisture content, and temperature and ________ of surroundings. - Matrix, composition, pressure 11. Diamond, silver, copper, brass, lead, and steel are good examples of ____________. - Conductor 12. Glass, body fat, wood, air, and styrofom are good examples of _____________ - Insulator 13. Freesers are categorized into _______ refiegeratiors and _______ freezers - mechanical , cryogenic 14. Evaporation and compression of a refigeratn and heat transfer through heat exchager is what? - Mechanical 15. What is it called when liquid nitrogen and carbon dioxide come in direct contact with food? - Cryogenic 16. Selection of freeing equipment are ______ of freezing, size, shape and ______ requirement, and batch or _______ operation - Rate, packaging, continuous 17. Types of freezers: _____ air, cooled ______ or immersion, cooled surface or ______ contact, and _______. - Cooled, liquid, direct, cryogenic 18. Chest freezers are ____ air. - Still 19. Ches freezers are _____ (natural circulation) at -___C to ___C. - Stationary, -20 to -30 a. Freezing rates are very ____ and used for ______ only - Low, storage 20. Blast freezers are ____ air. - Forced a. Air ______ over food from -___ C to - ____C with a velocity of 1.5 to ___ m/s - Circulated, -20 to -40, 6 21. What freezers are trolleys stacked with trays or a conveyor belt which carries the food through an insulated tunnel at a given rate? - Continuous 22. What freezers have many belts and the products falls from one belt onto another which break up clumps? - Multipass 23. Air flow is ________ or ______ to the food. - Perpendicular, parallel 24. Blast freezing is relatively ______ and very ________ - Cheap, flexible 25. Large air flow results in ________ burn and _______ degradation due to mositre loss in the unpackaged food. - Freezer, oxidative 26. “_____ over” of coils/plates requiring frequent ______ of system - Frosting, defrosting 27. You can prevent freezer burn by ____-____ with high humidity ai then quickly freeze to provide ____ exposure to moisture loss - Pre-chll, minimum 28. You can prevent freezer burn by _____ the product to give a _______ glaze or coating of ice then quickly freeze to prevent moisture from leaving the product - Wetting, sufrace 29. Simple blast freezer 30. Spiral freezers are ______ freezers - Belt a. Very _______ - Common b. _________ air-blast freezers are ______ mesh belt formed into spiral tiers - Modified, flexible c. Food is ______ through the freezer to chamber on belt - Carried d. What is it when cold air or sprays of liquid nitrogen directed down through the stack? - Small space requirements e. Low ______ costs, automatic __________ and unloading, and ________. - Maintenance, loading, flexible 31. Fluid bed freezers are ________ blast freezers where -____ to -___ C air passed at high _____ through _____ that carries food - Modified, -25 to -35, velocity, mesh 32. Required ___________ mist be high enough to cause ___________ - Velocity, fluidization 33. Very ______ freezing due to good mixing and very short freezing times and less _________ - Even, dehydration 34. What does IQF stand for? - Individually quick frozen 35. What are two examples of IQF? - Peas, corn 36. Cooled liquid or immersion freezers are when food i bt though a bath of refriegertate _______ glycol, brine gycol or _____ chloride solution on a submerged ______ belt. - Propylene, calcium, conveyor a. Liquid in not ____________ - Evaporated b. Low ______ costs and high rates of heat __________ - Capital, transfer c. Examples of this are ________ in molds or sausage in _______ - Popsicle, casings 37. For immersion freezer you have to consider: a. ________-shaped pieces freeze evenly due to direct ______ between food or package - Irregularly, contact b. _________ must be non-toxic ith no flavors or colors - Refrigerants c. Contact with air is _______ - Minimum d. Refrigerants must be non-_____to food packages - Toxic 38. ______ freezers are also cooled surfaces or direct contact fezers - Plate a. A _______ of vertical or horizontal hollow ______ through refrigerant is pmped at -____C - Series, plates -40 b. Slight _____ between food and surface may be applied to improve heat transfer - Pressure c. Good ______, low _______costs, little _____, and high rates of heat transfer - Economy, operating, dehydration d. Example: _______ vegetables - Boxed 39. Scraped surface freezers are _____ or semi-_____ foods similar to equipment used for _____ or crystallization  - Liquid, solid, evaporation a. _________ refrigeration system with ______ brine or _________ - Mechanical, ammonia, flurocarbon b. _____ ______ manufacturing incorporates air into product - Ice cream c. Keeps cold wall free of an insulated food _________ - Layer d. _____ ice crystals off the wall - Shaves e. Food remains in ______ - Motion 40. Cryogenic freezers change the state of the refiergatn as heat is ________ from the food - Absorbed a. Heat is removed via ______ heat of __________ or sublimation - Latent, vaporization b. Typical refrigerant are _______ or solid/liquid ______ ______ - Nitrogen, carbon dioxide c. High ______ rates, extremely high heat transfer rates, quialtiy ____________ due to quickness - Production, maintained d. Could cause heat _______ and potential _____ of freiegernat in foods - Shock, residues 41. Slow freezers are ___ air and ____ storage freezers - Still, cold 42. Quick freezers are air _____ and ____ freezers - Blast, plate 43. Rapid freezers are ______ bed freezers - Fluidized 44. Ultrarapid freezers are _______ freezers - Cryogenic