Summary Class notes - Milk in the Dairy Chain

- Milk in the Dairy Chain
- Kasper Hettinga
- 2020 - 2021
- Wageningen University (Wageningen University, Wageningen)
- Voeding en Gezondheid
436 Flashcards & Notes
2 Students
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Summary - Class notes - Milk in the Dairy Chain

  • 1603666800 Introduction & Milk composition

  • Which animals species produce milk?
    Mammals (zoogdieren)
  • Milk is produced by mammals. Is milk production unique to mammals?
    No, pigeons also produce milk....

    Ze weken het voedsel, waardoor het een soort van melk wordt, maar het is te debatteren...

    When is it called milk..?
  • Can mammals lay eggs?
    No, only the platypus (vogelbekdier) and the echidna (mierenegel)
  • Is perspiration (sweating) unique to mammals?
    Yes, only mammals produce sweat
  • Give examples of dairy products and diary ingredients
    Dairy products

    • Yoghurt
    • cheese
    • butter
    • ice cream
    • condensed milk
    • chocolate milk
    • butter milk
    • whipped cream
    • vla
    • quark/kwark

    Dairy ingredients
    • Taxi
    • Rivella
    • Medicine
    • Animal feed
    • Infant formula
    • pancakes
    • meat replacers
    • plastics
    • protein powder
    • tortellini
  • Important to realise about what milk is used for 

    • Fresh dairy products are most visible, but a small volume
    • Most dairy processes result in multiple product streams 
    • Many products streams are used to produce a wide range of ingredients 
    • A lot of dairy R&D is specifically on these ingredients: improvements for, amongst others, nutritional reasons 
  • Two examples of the importance of taking into account the whole dairy chain
    1. Nutrition & sustainability
      1. Is milk health
      2. nutrition -- consumer
      3. sustainability -- people that study cows
      4. there need to be a balance between the two
    2. Natural milk lipase
      1. NML
      2. NML cleaves free fatty acids (FFA) from triglycerides
      3. FFA cause serious off-flavours
      4. FFA cannot be removed from the milk 
      5. Fat globule membrane protects against NML
      6. Membranes become damaged after agitation of milk, especially if air is present 
      7. pasteurization inactivates NML
    2. Microbial lipase 
      1. ML
      2. same chemical reaction as NML
      3. ML are mainly produced by psychrotrophic bacteria 
      4. psychtlphic bacteria grow at low temperatures 
      5. Lipolytic enzymes not sensitive to heat (zodra het erin zit krijg je het er niet meer uit)
  • Milk fat rancidity 

    1. hygienic milking (to prevent entrance of psychrotrophic bacteria), 
    2. gentle treatment of milk (at farm and factory 
    3. and cold storage (at farm and factory) 

    are all needed at the same time 
  • The chemical structure of a triacylglyceride (triglyceride)
  • The main milk lipids are
    Triacylglycerides (TAG)
  • How is the dairy production chain looks like?
    This figure shows the direction of the product going from farm to consumer. 

    However, it is not a one-way process, because the consukmers demand products, which have consequences for the whole dairy chain. 
  • What is the definition of farmers milk
    Farmers milk is the product that has been secreted from the lacteal gland of one or more cows and which has not been heated above 40 degrees Celsius or did not have had a treatment comparable with that.
  • What is the composition of milk?

    Average content in milk (% w/w)Water  --  86.6
    Solids-not-fat  --  9.0
    Lactose  --  4.6 
    Fat  --  4.4 
    Protein  --  3.4 
    Casein  --  2.7 
    Minerals  --  0.7 
    Organic acids  --  0.17 
  • There are many factors that can affect milk composition (4)
    Cow breed
    Feed composition
    Seasonal and geographic variation 
  • Hoe ziet melk eruit onder een microscope?
    Milk fat globules in cows' milk range is size from 0.1 to 10 micrometers. Casein micelles range in size from about 10 to 300 nanometers 

    This picture illustrated that milk is a partially stable emulsion of milk fat globules (middle) in the plasma phase. In the bottom picture, the casein micelles are in a colloidal suspension in the serum phase of milk. 
  • Put the relative size of the following components in order from small to big

    Casein micelle; fat globule; whey protein 
    Whey protein; casein micelle; fat globule 
  • What are the major fatty acids found in milk fat?

    (fatty acids are composed of a hydrocarbon chain and a carboxyl group)
    Saturated & Unsaturated

    Myristic 11.1
    Palmitic 27.9
    Stearic 12.2
    • samen 2/3 of milk fatty acids 

    Oleic 17.2 (unsaturated)
  • While the cis form of unsaturated fatty acids is most common found in nature, approximately 5% of all unsaturated bonds of milk fatty acids are in the trans form as a result of hydrogenation by rumen bacteria of the cow
  • Fatty acids have widely varying melting points. The shorter the chain length and the greater the number of double bonds, the lower the melting points.

    But other variables also affect the melting point:
    • position of double bonds
    • configuration of double bonds
      • cis-unsaturation deceases and trans-unsaturation increases melting point
    • odd-numbered and branched chains have lower melting points
  • MFGM = milk fat globule membrane
  • What is the protein composition?
    • Depending on species 2-4 different caseins 

    Serum (whey) proteins
    • Always alfa-lactalbumin 
    • 100's of other proteins depending on specie 
  • What is the concentration of proteins in milk in % of total protein
    Total Protein -- 100

    Total Caseins -- 79.5
    • alfa s1 -- 30.6
    • alfa s2 -- 8.0 
    • beta -- 28.4 
    • kapla -- 10.1

    Total Whey Proteins -- 19.3
    • alfa-lactalbumin -- 3.7
    • beta-lactoglobulin --9.8
    • BSA -- 1.2
    • Immunoglobulins -- 2.4 
    • NPN and prothese peptone -- 2.4 
  • The casein content of milk is about 78% of total milk protein. We can distinguish as1 , as2 , B , k casein, representing approximately 38%, 10%, 36%, 12% of the total casein, respectively
  • What are the proteins present in Serum?
    • Alfa-lactalbumin
    • Beta-lactoglobulin
    • Blood serum albumin (BSA)
    • Immunoglobulin (A, G, M)
    • Many other proteins in low concentrations

    - serum proteins are globular proteins, like most other proteins in nature
    - Denatured during heating, precipitation on casein micelles
  • Casein micelles are stabilised against aggregation by the protruding hairs of kappa-casein.

    Deze kappa haren zijn van belang bij het maken van kaas. Door het verwijderen van deze haren zullen de micelle aan elkaar klonteren waardoor er kaas wordt gevormd 
  • Lactose is a disaccharide made up of the monosaccharides ... ...
     glucose and galactose
  • Lactose content is about 4.6% of milk, 50% of milk solids-not-fat, and 70% of whey solids. 

    Lactose is not as sweet as sucrose
  • What is the most important function of lactose in dairy processing?
    Its utilisation as a fermentation substrate in the production of many fermented dairy products.

    (Het wordt gebruikt als fermentatiesubstraat bij de productie van veel gefermenteerde zuivelproducten.)
  • Lactose is relatively insoluble
  • What kind of fat and water soluble vitamins includes milk?
    Fat soluble 
    • A
      • derived from retinal and beta-carotene
    • D
    • E
    • K

    Water soluble 
    • B1 - thiamine 
    • B2 - riboflavin 
    • B3 - niacin 
    • B5 - pantothenic acid
    • B6 - pyridoxine 
    • B12 - cyanocobalamin 

    There is also a small amount of vitamine C (ascorbic acid) present in raw milk, but that is very heat-labile and is therefore easily destroyed during pasteurisation.
  • Overzicht van de melk composition and structure
  • Fatty acids composition of milk. Is there a specific melting point?
    No there is not a specific melting point, because every fatty acid has a different melting point. It has a melting range.
  • What are the characteristics of fatty acid patterns of bovine (runder) milk fat?
    • Fatty acid composition very wide
    • high proportion (15-20%) of short-chain fatty acids, with 4-10 -carbon atoms (typical for ruminants)
    • high proportion of saturated acids (60+ mol%)
    • Oleic acid (is the most important) (unsaturated)
    • Wide variety of unsaturated acids
  • What are the causes of variability in yield and composition?
    • Lactation stage (colostrum)
    • Animal health (mastitis)
    • species
      • breed
      • genetic variation
    • farm management
      • feed
      • breeding
      • maling frequency
      • milking and storage of milk
  • There is variation in composition between breeds
    • Friesian (in the Netherlands)
    • "Friesian" (other sources)
    • Brown Swiss
    • Jersey 
  • Immune proteins - immunologically-active milk proteins
  • Dit is in alles zo
  • The are 3 main variations in different components
    1. Protein/fat/lactose
    2. Casein
      1. whah ratio rather constant, composition whey proteins much more variable 
    3. milk isotonic with blood 
      1. osmotic pressure through lactose and dissolved salts 
  • Effect of lactation stage
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Which one has the most energy consumption (heat treatment, evaporation, drying)per ton powderper ton waterthe highest costs
  • Total energy consumption per ton powder
    • mainly evaporation and drying
  • Largest energy consumption per ton water 
    • evaporation by far
    • drying
  • Capex and Opex costs
    • drying is the most costly by far
What percentage of dairy farms worldwide has < 10 cows?
Milk is produced by mammals. Is milk production unique to mammals?
No, pigeons also produce milk....

Ze weken het voedsel, waardoor het een soort van melk wordt, maar het is te debatteren...

When is it called milk..?
What are the 3 nutrients to limit
  • Saturated fat 
  • Added sugars
  • Sodium 
What are the 9 nutrients to encourage
  • Protein 
  • Fiber
  • Iron 
  • Calcium 
  • Potassium 
  • Magnesium 
  • Vitamin A
  • Vitamin C
  • Vitamin E
What happens with the milk fat content ifincrease forageincrease dietary unsaturated fatty acidsEnergy shortage
Increase forage: concentrate higher milk fat content
  • rise in milk fatty acids precursors
  • reduction in trans fatty acids
  • not if forage is high in unsaturated fatty acids (fresh grass)

increase dietary unsaturated fatty acid: lower milk fat content
  • formation of trans fatty acids
  • example: grass more C18:3 than grass silage

Energy shortage (body fat mobilisation): higher milk fat

higher milk fat content usually (not always) coincides with more short chain and less unsaturated fatty acids 
When can there be a shift in isomerization pattern
Low rumen pH
high level unsaturated FA in diet 
How to reduce the rate of biohydrogenation?
  • Prevent formation of free fatty acids (protection)
    • Ca-soaps
    • Encapsulation using formaldehyde treated proteins 
  • Reduce proportion of dietary fibre
    • pH reduction 
    • Shift in microbial metabolism 
  • Increase dietary unsaturated fatty acids level 
    • All fatty acids, particularly EPA and DHA
    • Shift in microbial metabolism 
  • Shift in isomerization pattern: trans-10 formation 
The role of SCD
  • Synthesis of significant amount of cis-9 C18:1 
    • ±40% of C18:0 converted into cis-9 C18:1
  • Synthesis of almost all CLA (cis-9, trans-11 C18:2)
    • amount depends on supply of trans-11 C18:1
    • 70-90% of all CLA from desaturase activity 
Which factors are key in getting a succes
Alle rode dingen samen geven 59% succes