NUFS 100

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KK37
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200461
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NUFS 100
Updated:
2013-02-14 03:02:54
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Nutrition Food Science
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Nutrition and Food Science 100. U of A. Wismer, Wendy
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  1. food science vs agri-food industry
    • Food science: system taking food from farm gat to consumer plate
    • Agri-food industry: primary agriculture and subsequent food products
  2. Food industry major segments
    • Production
    • manufacturing
    • distribution
    • marketing
  3. Major food industry commodities
    • Cereal and bakery products
    • meats, fish and poultry
    • dairy
    • fruits and veggies
    • sugars and confectionery
    • fats and oils
    • beverages
  4. allied industries
    do not sell food directly but are involved in the industry. Ex. packaging, colouring and flavoring, chemicals, machinery, regulating agencies.
  5. 2 overall perspectives of the food industry
    • 1) Customers have 2 things: time and money. try and take as much money!
    • 2) Food is a necessity: it should not be a merchandise.
  6. History of Food Industry/major processes
    • Thermal processing (Nicholas Appert)
    • Pasteurisation (Louis Pasteur)
    • Canning
    • Refrigeration
    • Frozen foods
    • Nutrient Identification
    • Freeze drying
    • Computer controled processing
    • Plastic containers
    • Re-engineering of proteins
    • Plant sanitation/automation
    • Energy efficiency
    • RTE Frozen Entrees
    • aseptic packaging
    • microwave ovens
    • Increased nutrition health, convenience  and food safety concerns
  7. Why do we eat?
    • Nutrients
    • social aspect of food
    • consumer trends
  8. Food Habits
    • The way in which we use food:
    • Belonging
    • status
    • security
    • self-actualization
    • self-definition
    • celebrations
    • symbols
  9. Why do societal demands of food industry change?
    • Affluence allows for questioning and consumer control
    • Greater awareness of self health
  10. Chemical constitution of food
    • Charbohydrates (& sugar free sweetners)
    • Protein
    • Fat
    • Water
  11. Proximate composition of food (5 major categories)
    • Provides info to help processing, storage/shelf-life, energy values, and confoms to legal definitions/identities of foods
    • Fat
    • Carbs
    • Protein
    • Water
    • Minerals/Ash
  12. Methods of Proximate analysis
    • Kjeldahl (sulphuric acid digestion, protein)
    • Soxhlet (solvent extraction, lipids)
    • vacuum oven (drying, water)
    • Muffle furnace (wight of ash, minerals) 
    • Leftovers = Carbs
  13. Kcal/g for macronutrients
    • carbs=4
    • protein=4
    • fat=9
    • alcohol=7
  14. Carbohydrates
    • form a ring, then chains
    • mono and disaccharides=simple sugars (glucose, fructose, ect)
    • oligosaccharides
    • polysaccharides=complex carbs
  15. Sugars pourpose
    Sweetness

    Humectant/hygroscopic: ability to hold water & therefore preserve.

    food for yeast

    • Give structure
    •  
    • Chemical reactions (carmelisation & Maillard reaction)
  16. Complex Carbs & pourpose
    • Starch (modified starch= stable to heat)
    • cellulose (hemi-cellulose, lignin)
    • pectin (thickens)
    • Pourpose: 
    • Thicken
    • Form gels
    • Bind water
    • Stabilise proteins
    • Prebiotics & probiotics
  17. Sugar free sweetners
    • Aspartame (180x sweeter than sucrose, protein=4Kcal/g)
    • Sucralose (Splenda, 600x sweeter, indigestible)
    • Stevia (Low cal plant derivative)
  18. purpose of protein
    • colour (maillard reaction)
    • Foams
    • Thickening
    • Texture
    • Fat reduction
  19. Purpose of fats
    • add calories
    • flavour
    • fat soluble vitamins
    • texture
    • heat transfer
    • oxidation (chemical reactions)
    • rancidity
  20. aw
    Water activity: dimensionless ratio that describes "free water".

    Reduced by addition of salt and sugars (small compounds tie up more moisture)

    • aw < 0.60 no microb growth
    • aw < 0.90 no microb spoilage
    • aw < 0.80 no yeast
    • aw < 0.70 no molds

    water also effects freezing and heat transfer
  21. Food acids
    • Generally COOH
    • adds flavour
    • antimicrobial
    • low hygroscopicity
  22. Food composition change during processing?
    Only Vitamins and minerals are generally affected by processing
  23. Food forification
    supplementation to provide additions or to restore lost nutrients
  24. microbes in food
    Bacteria, yeast, and mold

    • food fermentation
    • food spoilage
    • food borne illness
  25. factors affecting microb growth
    • nutrients
    • water acctivity
    • acidity
    • oxygen
    • temperature
  26. durable life
    the period (starting on the day of packaging) that the food will retain its normal wholesomeness
  27. Foodborne illness
    • Food intoxications: bacterial toxin in food
    • Food infections: high number of pathogens ingested
    • Toxin-mediated infection: pathogen from food produces toxin once ingested
  28. danger zone!
    anything lower than 60 degrees and higher than 4 degrees should only be allowed for 2 hours.
  29. GMP
    Good Manufacturing Practices
  30. SOP 
    Standard Operating Procedures
  31. Three major preservation processes
    • Drying
    • Freezing
    • Thermal processing (canning)
  32. Processing
    converting/handling commodities into edible food products
  33. preservation
    • ensuring safety and extending shelf life through prevention of decay, spoilage and contamination
    • goals: min spoilage, max safety, maintain nutrition
  34. Unit operation in food processing
    • Materials handling
    • separating
    • cleaning
    • disintegrating
    • pumping 
    • mixing
    • heat exhange
    • evaporation
    • drying
    • forming
    • packaging
    • non-thermal methods
  35. value-added
    food which value has been added through special growing, processing or packaging
  36. categories of manufactured foods
    • Primary: basic modification
    • Secondary: combination of ingredients to form new foods
    • Tertiary: complete food items
  37. types of spoilage
    • microbial
    • chemical
    • physical
  38. types of drying
    • sun drying (radiant heat)
    • hot air drying (enclosed environment)
    • spray drying (fluids sprayed into hot air)
    • fluidised bed drying (conveyor belt hot air)
    • Vacuum drying (decreased pressure = lower temp needed)
    • freeze drying (frozen food in a vacuum sublimes water out of food)
    • roller drum drying (past type food applied to heated drum)
  39. slow freezing
    creates large ice crystals-> damages cells-> "juices" released at thawing->loss of....-> poor quality.

    freezer burn is a result of dehydration
  40. freezing point of foods
    • freezing points are depressed by dissolved substances
    • meat=-1.5
    • vegies=-1.0
    • milk=-0.5
    • ice cream=-6.0
  41. freezing techniques
    • increase surface area and speed of freezing
    • Sharp freezing- air blasting
    • contact plate- scraped surface
    • liquid immersion- cryogenic feezing
  42. factors in thermal processing
    • microbial heat resistance
    • heat transfer ability of food
    • type and size of container
  43. D values
    Decimal reduction time: used to describe heat resistance of microbs and represents the time to destroy 1 log cycle (90%) of bacteria. 
  44. how much heat?
    depends on type and number of organisms
  45. 12D
    defines a commercially sterile product (probability that one in 10^12 can would have a botulinum spore).

    12 log cycle reductions
  46. Acid foods
    pH of 4.6 or less

    bacteria are easier to destroy with heat when in acid conditions (lower temp and time neded)
  47. Types of preservatives
    • acid
    • sugar and salt
    • smoke
    • chemicals
  48. acidulants
    food acids which control pH, combined with other techniques for preservation

    • acetic: flavour, decreases pH
    • benzoic: antimicrobial
    • phosphoric: flavour/tartness in beverages
    • propionic: antimicrobial
  49. Radiant heat
    • Microwave heating: exciting of h2o
    • Irradiation: limited for specific uses
    • Ohmic heating (OH): electric current heats at rapid rate, food needs water and electrolytes
  50. Hurdle Technology
    innovative non-thermal meathod combination of low level preservation. ex. aw, pH, temp, and antimicrobial all done together.

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