Processing vs food components - talg.ca · 2020. 2. 16. · Direct vs Indirect UHT. Department of...
Transcript of Processing vs food components - talg.ca · 2020. 2. 16. · Direct vs Indirect UHT. Department of...
Processing vs food components
Art Hill
Department of Food Science
University of Guelph
www.foodscience.ca
Department of Food Science | University of Guelph | Guelph, Ontario
Review: what is Food Science?
Food Science means to know (discover) the
chemical, biological, and physical properties
of food and how those properties change
during food processing.
The application of that knowledge is food
technology, which is about food process and
food product development. A key word in
food product development is differentiation.
Department of Food Science | University of Guelph | Guelph, Ontario
Why not just eat unprocessed foods?
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Department of Food Science | University of Guelph | Guelph, Ontario
Why not just eat raw foods?
• Preservation
• Flavour
• Texture
• Health
• Nutrition
• Safety
• Sustainability
• Convenience
• Differentiation www.primaverakitchen.com
Dairy Family Tree
Dairy E-book, University of
Guelph
Department of Food Science | University of Guelph | Guelph, Ontario
Preservation Processes (unit operations)
• Heating
• Modified atmosphere
• Ultraviolet radiation
• Electric pulse
• Microfiltration
• Packaging
• High pressure
• Ozone
• Hydrogen peroxide
• Cold plasma
• Finely dispersed w/o
emulsion.
• Cooling and freezing
• Drying
• Osmotic pressure
• Acidification
• Antioxidants
• Antibiotics
• Antifungal agents
• Biocontrol
• Fermentation
• Ionizing irradiation, γ-rays,
and x-rays
Department of Food Science | University of Guelph | Guelph, Ontario
Pasteurization: HTST
Department of Food Science | University of Guelph | Guelph, Ontario
Thermal Processing (milk)
Process(s) Temp Duration WPC Purpose
Raw or sub-
pasteurized milk <65ºC < 1 min <5%Full flavoured ripened
cheese
Vat
pasteurization63ºC 30 min 10%
Destroy all pathogens.
Reduce spoilage
HTST
pasteurization73ºC 16 s <5%
Destroy all pathogens
Reduce spoilage
Ultra-high
temperature140ºC <4 s 10%
Destroy all
microorganisms
Yogurt milk85-
90ºC4 – 6 min 80%
Denature whey proteins;
thicken yogurt
Department of Food Science | University of Guelph | Guelph, Ontario
Direct vs Indirect UHT
Department of Food Science | University of Guelph | Guelph, Ontario
Retort Sterilization
• Normally 121ºC
• Target 12 log reduction of
microbes (quadrillion to
one)
• Pouches and cans
• Denatures proteins,
deactivates vitamins and
enzymes.
• Alters pigments
• Softens many food
matrices
Department of Food Science | University of Guelph | Guelph, Ontario
Raw Milk
Separator
Cream Skim
Microfilter
Recombine Retentate
UHT Standardize Permeate
Pasteurize
Microfilter
Microfiltration Flow Chart
• Physical process
• Few chemical
changes
• Minimal effects on
enzymes and
vitamins
Department of Food Science | University of Guelph | Guelph, Ontario
High Pressure Processing
• High pressure transmitted
by water
• 3000– 6000 Bar
• Destroys vegetative cells
but not all spores and may
induce germination of
spores
• Denatures some proteins
including some enzymes.
• Accelerates cheese
ripening
Department of Food Science | University of Guelph | Guelph, Ontario
Spray Drying
• Spray drying
• Air inlet ≈ 125 -160ºC
• Air outlet ≈ 70 - 80ºC
• Product protected from
heat damage by heat of
vaporization.
Department of Food Science | University of Guelph | Guelph, Ontario
Vacuum/Microwave Drier
• Low temperature
drying achieved by
drying under vacuum to
lower boiling point.
• Energy for vaporisation
provided by
microwaves.
Department of Food Science | University of Guelph | Guelph, Ontario
Fermentation: bacteria, yeast, moulds
Department of Food Science | University of Guelph | Guelph, Ontario
Fermentation
• Enhance Food Safety and Extend
Shelf Life• Compete for nutrients
• Acidify
• Create anaerobic conditions
• Release antimicrobials
• Reduce water activity
• Promote Health• Probiotics
• Vitamins, bioactive peptides,
• Modify texture
• Create an endless diversification
of flavours.
Department of Food Science | University of Guelph | Guelph, Ontario