Pasteurization Pt 2 Flashcards
What is UHT processing?
- Ultra High Temp pasteurization -> sterilizes milk to make it shelf stable
Must be aseptically processed
What conditions are needed to achieve UHT?
- Temp > 135C for 2-3 sec
But in general must be >100 (time/temp depends)
What products are able to be UHT processed?
- Milk
- -Juice
- Cream
- Yogurt mix
UHT ADVANTAGES
List the advantages of UHT
- Quality of products
- Long shelf life
- Packaging size
UHT ADVANTAGES
Describe of UHT benifits quality:
- D & z values are larger for quality factors than MO’s (MO’s killed off faster than quality can be affected)
- Short time process kills MO’s with minimum quality decrease
- minimum come up and cool down time
UHT ADVANTAGES
What is the minimum shelf life for UHT products?
6 montsh (no refrigeration)
UHT ADVANTAGES
How does packaging size get benifited by UHT?
- b/c it is processed BEFORE packaging; container size is flexable
If packaged first, larger containers required + longer processing time
List the difficulties related to UHT processing
- Keeping sterility
- Particle size
- Maintaining quality
UHT Difficulties
Describe how sterility can be a difficulty:
- high sterile system is required, which needs a complex equipment setup (aseptic system)
Can be costly
UHT Difficulties
Describe the difficulties relating to particle size
- overcooking and transportation problems with large particle size - needs separate cooking process
UHT Difficulties
Discribe difficulties related to sustaining the quality of products
- Some enzymes may survive the process = flavor and texture changes
- Profound cooked flavour with UHT process
- Some vitamins are less in UHT than HTST
Examples:
Enzymes = lipases, proteases
Vitamins = Folatesetupa
What are two forms of direct heating?
1- Steam injection
2 - Steam infusion
Describe the setup of direct heating equipment:
Holding tube/tank and vacuum cooling
List the advantages and disadvantages of direct heating
Advantages = Fast heating
Disadvantages:
1 - diluted product due to the addition of steam
2 - volatile loss
3 - flavour change
1) What is indirect heating?
2) What equipment is required?
1 - Heating where the heating medium and product are not in contact
2 - heat exchangers
