7. Food Processing and Engineering Flashcards
Full name of WVTR?
Water vapor transmission rate
Isotherm water activity chart, x and y axis?
x: water activity y: moisture content
Define triple point?
Pressure-Temperature at which substance is at solid liquid and vapour phase at same time. For water is 611.73 Pa and 273.16 K.
In thermoprocessing what is the difference between sterility and commercial sterility?
Commerical sterility means the probability of spores and cells surviving is low but not absolute
Name 3 methods of food preservation
Drying/salt addition/heat/freezing
The most commonly used surfactants in the food industry are?
Monoglycerides and Diglycerides
What is IQF?
Individually Quick Frozen
Which test would you use to determine whether Coke is sweeter?
Increasing foam stability but decreasing foam value
Of the 4 components of a refrigeration system, which one involves constant entropy?
Compressor
Basic Principles of Food Processing
1) Moisture removal
2) Heat treatment
3) Low-heat treatment
4) Thermal processing
5) Nonthermal processing (traditional & nontraditional)
6) acidity control
What is the purpose of processing Food?
To preserve food and create a specific desirable food product
What is Food Spoilage?
Perishability of raw foods through microbial growth/enzymatic reactions/chemical changes (mainly through factors of water/temp/pH)
What is Unit Operations?
The processing step of a product like in a factory (i.e. heat exchange - evaporation - drying - material handling)
What is Heat Treatment?
Process of inactivating pathogens and spoilage microorganisms and enzymes
What is D-value?
The specific time at a specific temperature for a specific food to destroy 90% of the population (one log) of a specific MO
What is the 12D Concept?
The D-value to destroy 90% of C. Botulinum at a 12 log reduction: ensures safety of low acid foods
What is the purpose of thermal death time studies?
to determine an organism’s heat resistance (D-value) in a specific product to develop a process for that product
Define Acidity Control
The more acid present in a food the lower the pH becomes lowering the potential of microbial spoilage and requires less heat treatments
What is Traditional Nonthermal Processing?
Chemicals added to food for preservation to control aW and extend shelf-life through packaing
Name the Types of Traditional Nonthermal Processing
1) modified atmosphere packaging (MAP) 2) controlled atmosphere storage (CAS) 3) nitrogen flush packaging 4) vacuum packaging
What is Innovative Nonthermal Processing?
Refers to new technologies that preserve the food supply without raising the temperature; to eliminate thermal degradation of food quality
What is blanching?
Process used to inactivate enzymes and set color
What is Pasteurization?
Process used to inactivate pathogens (e. coli) and vegetative (alive) pathogens
What makes a product commercially sterile?
Free of all pathogens and other microorganisms that could potentially grow in the product
Why is commercial sterilization important?
To achieve long-term shelf stability for canned foods and other products: majority after being placed in container
What is conduction heating?
Uniform heating of the product from all directions with the slowest or coldest location at or near the center of the container
What is Convection heating?
(canned liquid) the first heated portion of the liquid becomes lighter in density and rises thereby setting up circulation within the can. coldest location at bottom of container
What is the purpose of refrigeration storage?
To extend shelf-life by slowing down derogatory reactions and limiting microbial growth
What is the refridgeration temperature range?
Temperature range - approximately -1 to 8 C
What are some ways of deterioration of product quality?
Chemical/Biochemical/Physio-chemical/Nutritinal
Name the 4 Biochemical reactions of product quality
Enzymic browning/Glycolysis/Proteolysis/Lipolysis
What is the Freezing/Frozen temperature range?
Freezing below the temp. at which ice crystals begin to form within the food -10 to -20C
Name 2 food freezing systems
Indirect contact and direct contact