Chap 4: Food Processing

Transformation of ingredients, by physical or chemical means into food or of food into other forms

• Refrigeration • Freezing • Evaporation • Dehydration • Homogenization

• Removal of heat • At or below 40 degrees F (4 degree C)

At or below 0 degrees F (-18 degrees C)

Individually Quick Frozen Clarence Birdseye (1920s)

• the process that changes liquid water to gaseous water (water vapor) • the partial removal of water from liquid food by boiling

• removal of water • water freezes and transitions directly from solid phase to gas phase (Sublimation)

• mixture of non-soluble liquids • same particle size throughout

Thermal: Heat used to enhance shelf life and palatability Non-Thermal: No or minimal heat used to eliminate or inactivate microbial contamination in food

the submerging of fruits or vegetables in boiling water or steam - mild heat treatment used to inactivate oxidative enzymes in fruits and vegetables (Time: 1 - 15min Temp: 70 to 100 degrees C)

a process that applies heat to destroy pathogens in foods (Louis Pasteur) - Inactivation of enzymes - Requires lowering the product temperature to below 4 degrees C (39 degree F) within 2 hours after pasteurization

UHT - Ultra High Temp HTST - High Temp Short Time LTLT - Low Temp Long Time LTST - Low Temp Short Time

• (usually) requires 250 degrees F (121 degrees C) • Achieve commercial sterilization • Destruction of all Sterile food is food free from all bacteria

Conduction Convection Radiation

Heat transferred from one particle of matter to another in an object without the movement of the object

The movement that transfers heat within fluids and gas. Currents occur within the fluid

Heat/Energy transferred by electromagnetic waves, does not require matter to transfer energy (fire/sun)

• Conventional (oven) is stationary and rises up from a heating element at the bottom • Convection (oven) heat is blown by fans, so the air circulates all over the inside of the oven. Heat is consistent (even heat)

utilizes short, high-frequency waves that penetrate food, which agitates its water molecules to create friction and transfer heat

• PUV • Irradiation • Chemicals CO2 Nitrogen

Decontamination - Herbs and spices Electromagnetic Waves - Detach electrons from atoms

Pulsed Ultra-Violet Light - High energy short pulse of a broad spectrum Photo-chemical Photo-thermal

• DNA altered • Small amounts of heat absorbed

Preservation - Package and shelf-stable foods