Milk: Composition and Processing Flashcards
Fluid products
Table milk, cream (26.7hL)
Derived (industrial products)
Cheese, yogurt, butter, ice cream, etc. (67.95hL)
Dairy industry is _________________
Supply managed
Consumption of dairy products
16.2 billion CAN$ in 2021 (11.6% of Canadian food/beverage sector)
3 largest dairy processors in Canada
Saputo, Agropur, Parmalat
By how much has milk production increased?
73.0M - 92.3M hL
Where are most dairy farms and processors found in Canada?
Ontario and Quebec
Main exporters of dairy
European Union, New Zealand, and US
Main Importers
European Union, Asian countries, and US
When the product is labelled milk ( or whole milk), it must fit into these categories
- must be obtained from the mammary gland of the cow
- shall contain added vitamin D that is not less than 300 international units and not more than 400 international units
5 major nutrition groups (milk must must contain all of these)
Carbohydrates, proteins, fatty acids, minerals, vitamins
Most common dairy cow breed in Canada
Holstein
Milk composition
Water, 87%; lactose, 4,9%; fat, 3.5-3.7%; proteins, 3.6%; ash, 0,7%
What is the most variable component in milk?
fat
Lactose (milk sugar)
the major carbohydrate and is a energy source for young animals (also affects physical and chemical properties in milk)
Fat (in milk)
present in milk in form of membrane enveloped globules
_________ is an important component of the globular membrane
cholesterol
Fat-soluble vitamins found in milk
A, D, E, K
What factors affect fat content of milk?
breed, individual animal, stage of lactation, milking frequency, season, feed, health of cow
Fat content function in foods
Lubrication (mouth feel), flavour, a reservoir of other flavour compounds, shortening effect, energy provider, nutrients
What kind of emulsion is milk?
Oil-in-water emulsion
2 types of protein
Particulate (casein) and soluble (serum, whey)
Casein protein
Heat stable and in the form of micelles
Whey/serum proteins
Easily denatured by heat and are the enzymes, antibodies, etc of milk
Ash
Minerals such as K, Na, Ca, Mg, P
Fat soluble vitamins
A, D, E, and K
Water soluble vitamins
B and C
How are vitamins lost?
Through fat seperation
Fluid milk
40% of production in Canada
Industrial Milk
60% of production
Table milk
Milk commonly found in households (skim or homo)
Creams
Elevated fat content relative to whole milk
UHT Products
Shelf-stable without refrigeration (sterilized)
Steps to processing milk
Clarified, standardized, vitaminized, homogenized, pasteurized, packaged, and stored
Clarification
Milk is centrifuged to remove particulate matter (dirt)
Standardization
Adjustment of fat content by removing some or all of butterfat by centrifugation
Vitaminization
Addition of vitamin A and D
Homogenization
Relatively large butterfat globules are disintegrated by shearing and impact
Pasteurization (most important process)
Heat treatment to destory pathogens and extend shelf life
3 types of pasturization
LT, HTST, UHT
LT pasteurization
63 degrees celsius, 30min
HTST pasteurization
72 degrees celsius, 16sec
UHT pasteurization
140 degrees celsius, 5 sec
Target microorganism in pasteurization
Coxiella burnetii
Cooling
to storage temperatures
Packaging
Poured into cartoons, polyethylene film, or bottles
Storage
Kept at less than 4.5 degrees celsius
Cultured products
Products like yogurt, sour cream, buttermilk, cottage cheese, etc created by bacteria converting lactose to lactic acid
Important enzyme to make cheese
Rennin (chymosin) enzyme that causes precipitation of casein (curds)
What part is drained away in cheese making?
the whey
Evaporated and condensed milk
Around 50% of water is removed by vacuum evaporation
Butter
Produced by churning to transform oil-in-water emulsion into water-in-oil emulsion
Process for clustering and clumping when making butter
- Flocculation
- Partial coalescence
- Coalescence
