Blanching Flashcards
What is the importance of blanching in seafood processing?
- Preservation
- Texture Retention
- Food Safety
Benefits of blanching seafood products?
• Color Retention
• Microbial Growth
• FlavorLock
• Improved Texture
Blanching Methods Used In Seafood Industry
- Water Blanching
- Steam Blanching
- Microwave Blanching
Factors to consider when blanching seafood products
• Blanching Duration
• Water Quality
• Tenperature Control
Common Challenges & Solutions in Blanching Seafood
a) Overcooking
• C: Risk of texture & flavor degradation
• S: Proper timing & temperature control
b) Uneven Blanching
• C: Inconsistent texture & color
• S: Use of appropriate blanching equipment
c) Microbial Contamination
• C: Threat to food safety
• S: Strict adherence to hygiene & sanitation protocols
What are the types of pasteurization of unpackaged food?
- Low - Temperature - Long - Time (LTLT)
- High - Temperature - Short - Time (HTST)
What is LTLT?
• Typical batch method
How does LTLT work?
- A quantity of milk is placed in an open vessel
- Then, they are heated to 63°C and held for 30 min
How does HTST work?
• Involves heating to 72 - 75°C and being held for 15 - 20 s before it is cooled
• The shelf life depends on the quality of the raw milk and the degree of refrigeration
Batch Pasteurization
• In the vessel, the food is heated and held throughout the holding period while being agitated
• The milk may be cooled in the vessel OR removed hot after the holding time is completed for every particle
Continuous Pasteurization
• Time & energy saving compared to batch
• HTST pasteurizer is used (use a plate heat exchanger)
What is UHT (Ultra High Temperature)
• Product is rapidly heated to temperatures ranging from 130°C - 150°C for a few seconds
Define aseptic processing
• Product and the Package is STERILISED SEPARATELY, then the package is filled with the sterile product & sealed under sterile conditions
Define retort processing
• Product is packed into a container
• The container is then sterilized
• A common retort temperature for sterilizing canned foods is 121 °C
Factors affecting sterilization
- Microorganism present
- Properties of the food product
- pH of the product
- The products initial temperature
Decimal Reduction Time (DT
: the time it takes to reduce a microbial population by 1 logarithm, or 90% of its initial value
Thermal death time constant (thermal resistance constant), z
temperature required to make 90% reduction of DT
Thermal death time, TDT (Fo) or process lethality
amount of time that is necessary to kill a specific number of microbes at a specific temperature.
Heat processing using steam or water
Blanching
Pasteurisation
Heat sterilization
Heat processing using hot air/oil
Dehydration
Baking and roasting
Frying
Processing by the removal of heat
Chilling
Freezing
Freeze drying
Mild Heat Treatment
• Aims:
Reduces bacterial load (Food is NOT sterile)
Inactivate enzymes
• Advantages:
Minimal damage to flavor, texture, and nutritional quality.
• Disadvantages:
Short shelf life
Another preservation method must be used, such as
refrigeration or freezing
• Examples:
Pasteurization
Blanching
Severe Heat Treatment
• Aims:
Kills all bacteria
Food will be commercially sterile
• Advantages:
Long shelf life
No other preservation method is necessary
Disadvantages
Food is over-cooked
Major changes in texture, flavor, and quality
• Examples:
Sterilization/Canning
Thermal processing
Heating packed/unpacked food for a specific time at a specific temperature to eliminate the microbial pathogens that endanger public health and microorganisms and enzymes that deteriorate food during storage.
