Chpter 6 FREEZING AND FROZEN-FOOD STORAGE Principles of freezing DESCRIPTION OF FOOD FREEZING SYSTEMS INDRECT-CONTACT FREEZING SYSTEMS DIRECT-CONTACT FREEZING SYSTEMS INDIVIDUAL QUICK FREEZING (IQF) ESTIMATION OF FREEZING TIME FOOD FREEZING AND PRODUCT QUALITY SUMMARY
Chpter 6 FREEZING AND FROZEN-FOOD STORAGE Principles of freezing DESCRIPTION OF FOOD FREEZING SYSTEMS INDRECT-CONTACT FREEZING SYSTEMS DIRECT-CONTACT FREEZING SYSTEMS INDIVIDUAL QUICK FREEZING (IQF) ESTIMATION OF FREEZING TIME FOOD FREEZING AND PRODUCT QUALITY SUMMARY
Problem ◼ Explain the cause of freezing temperature depression. ◼ Why should we use rapid freezing process? ◼ How many factors influence the freezing time? What are they? ◼ What changes occur to the product during freezing? ◼ Why the storage temp. should be kept in constant?
Problem ◼ Explain the cause of freezing temperature depression. ◼ Why should we use rapid freezing process? ◼ How many factors influence the freezing time? What are they? ◼ What changes occur to the product during freezing? ◼ Why the storage temp. should be kept in constant?
vocabulary ◼ freeze, ice crystals , irreversible, negative changes, latent heat of fusion , depression of the freezing temperature , supercooling region , freezing plateau , solutes , depression of the freezing temperature, freezing-point depression , freezing- temperature depression, eutectic temperature
vocabulary ◼ freeze, ice crystals , irreversible, negative changes, latent heat of fusion , depression of the freezing temperature , supercooling region , freezing plateau , solutes , depression of the freezing temperature, freezing-point depression , freezing- temperature depression, eutectic temperature
vocabulary ◼ barrier, air blat system, spiral conveyor, fluidized bed, immersion, cryogenic, tunnel, spray of liquid refrigerant, intimate contact , fundamental, estimation, critical, individual, freezing medium, Plank's equation, temperature gradient, thermal conductivity, cylinder, cylindrical, sphere, spherical, infinite plate, convective heat transfer coefficients
vocabulary ◼ barrier, air blat system, spiral conveyor, fluidized bed, immersion, cryogenic, tunnel, spray of liquid refrigerant, intimate contact , fundamental, estimation, critical, individual, freezing medium, Plank's equation, temperature gradient, thermal conductivity, cylinder, cylindrical, sphere, spherical, infinite plate, convective heat transfer coefficients
Freezing Process ◼ The freezing process is the removal of thermal energy from the food product to the extent required to reduce the temperature below the freezing temperature of water. The thermal energy removed as a part of freezing is primarily latent heat of fusion required to convert water to ice within the product
Freezing Process ◼ The freezing process is the removal of thermal energy from the food product to the extent required to reduce the temperature below the freezing temperature of water. The thermal energy removed as a part of freezing is primarily latent heat of fusion required to convert water to ice within the product