Milk Flashcards by Sophie Lamontagne

Define the chemical composition of milk. What is the emulsion, the suspension? What is it suspended in?

Milk is an emulsion of fat globules and a
suspension of casein micelles suspended
in an aqueous milk serum phase

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Where is milk secreted from? What is it used for?

White yellowish secreted from the
mammary gland to serve as nutrition for
the newborn

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Where and when does milk originate from?

People have been using milk for thousands of years

Dates to ancient Babylon, Egypt and India

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What is milk a source of?

o Complete protein
o B vitamins
o Vitamin A
o Vitamin D
o Calcium

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What is the % of calcium consumed from dairy?

80%

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What do the proteins in milk do during during food processing?

Proteins used in processed foods to improve nutritive value

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What do the caseinates in milk do during food processing?

Caseinates used as emulsifying and stabilizing agents

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How does lactose help for baked goods?

Lactose helps with browning of baked goods

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What does dairy alter during food processing?

Used to alter texture, flavor, moisture, protein content

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What is the composition of milk?

H2O: 87%
CHO: 5%
Fat: 3.7%
Protein: 3.4%
Minerals: 0.8%

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Name the 2 components of milk solids.

Milk solids non-fat

- Milk solid fat

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Name the 3 components of milk solids non-fat

Lactose, Protein, Minerals

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What are the 2 types of proteins that can derive from milk?

Casein protein

- Whey protein

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What nutrients does milk lack?

Vitamin C & E
Iron
Complex CHO
Fiber

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Which amino acid is in milk? Which B vitamin is specifically in milk?

Tryptophan and vitamin B2 (riboflavin)

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What % of calcium RDI is in a glass of milk? Protein? Calories?

30% calcium
16% protein
85 kcalories

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Which protein is the primary protein found in milk?

Casein

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Which milk protein can be added to foods as an emulsifier?

Whey

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How is casein extracted?

Extracted by acid or enzymes (rennet)

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Which milk protein is the liquid portion of milk?

Whey

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What is whey composed of?

Lactalbumin and lactoglobulin

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Which milk protein can be added to improve nutritional value?

Casein AND Whey

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Which milk protein separates from curd during cheese production?

Whey

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What else can whey do?

Improves mouthfeel, moisture retention and flavor

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How many fatty acids are in milk fats?

Over 400 FA

What is the most variable component in milk?

Milk fat

What are the roles of milk fat?

Contributes to flavor, physical (mouth feel), and chemical properties

Describe the structure of milk fats.

Triglycerides surrounded by phospholipid protein membranes

Name the 2 short chain fatty acids in milk fat.

Butyric acid, caprylic

Name the 3 fatty acids in milk fat.

Myristic, palmitic, stearic

What are the components of the fatty acids in milk fat?

o Saturated FA = 66% o Monounsaturated FA = 30% o Polyunsaturated FA = 4%

Which milk protein the one that is found in the largest amount?

Casein

What is the Framingham Heart Study?

Longitudinal association (since 1948) between dairy consumption and changes of body weight and waist circumference

How many different types of caseins?

Alpha, Beta, Kappa, y

Which type of casein prevents milk from coagulating?

Kappa

Which type of milk protein coagulates? Which stays in solution?

Coagulates: Casein Solution: Whey

Is there evidence that milk increases the risk of heart disease and obesity?

No not yet, | People who drink 1-3 milk drinks per day are less obese and have a smaller waist circumference

Why aren't people who drink more milk obese?

Since fat and protein (in milk) increase satiety (fuller for longer)

How many carbohydrates per cup of milk?

12g

What is the primary CHO found in milk?

Lactose

What turns lactose to lactic acid? What does it do?

Bacteria | Gives flavour to cheese, yogurt, sour cream

Name a couple of sources of milk from Canada's food guide.

- Milk (250 mL) - SKIM (1 or 2% bcos high in sat fat) - Yogurt (3/4 cup) - Cheese (50 grams)

Define lactose intolerance.

- A condition in which a person is unable to digest lactose - Insufficient quantities of lactase brush border enzyme

What are the symptoms of lactose intolerance?

 Abdominal cramps/ bloating  Flatulence  Nausea  Diarrhea

Which ethnicity has a genetic advantage in terms of lactose intolerance?

European descent

Lactose intolerance affects how many Canadians? Americans?

- 7 million Canadians | - 30-50 million Americans

Why can lactose intolerance develop?

Lactase can go down throughout adulthood

Milk allergies occurs in what percentage of infants?

Occurs in 2-7.5% of infants

Which protein is the antigen that the body reacts to?

B-lactoglobulin

What are the symptoms of milk allergy?

``` Vomiting o Nausea o Wheezing, chronic cough o Skin rash o Headaches ```

Name some sources of milk alternatives.

``` Soy milk oRice milk oAlmond milk oCashew milk oCoconut milk oHemp milk ```

What is the issue with milk alternatives?

Since most (apart from soy) do not have nearly as much protein as regular milk

Name 2 nutrients milk is fortified with.

- Vitamin D | - Vitamin A

Why is milk fortified with vitamin D?

oFound naturally in few foods so it was added to milk – a staple o To prevent the incidence of rickets in children o Prevent osteoporosis

Why is milk fortified with vitamin A?

Vitamin A naturally found and is a fat soluble vitamin | o When fat content is reduced – vitamin A is lost

What are the different pasteurization types? What makes them differ?

- Pasteurization - Ultrapasteurization - Ultrahigh-temperature pasteurization (sterilizing) DIFFER BASED ON TEMP AND TIME

Name characteristics of regular pasteurization.

Heating milk below it’s boiling point for a short time to reduce foodborne illness o Destroys 95-99% of pathogenic and non-pathogenic bacteria, yeasts and molds o To ensure adequacy – food processors measure alkaline phosphatase activity, an enzyme found in milk - most commonly used

Name characteristics of ultrapasteurization.

Uses higher temperatures for shorter amount of time o 15 second process o Extends shelf life

Name characteristics of ultrahigh- pasteurization.

o 2 second process | o Sterile packaging technique

How does industry know if milk is properly pasteurized

Measure alkaline phosphatase

Why does fat float to the top of milk when raw?

Fat is less dense than water

What does homogenization prevent?

Creaming, thick yellowish layer of cream

Does the mechanical process of homogenization have an effect on the nutritional value?

How does homogenization coagulates quicker? What is this good for?

- In presence of heat | - Good for making pudding, white sauces and cocoa

Name some examples of cultured dairy products (microorganisms added).

Buttermilk, yogurt, acidophilis milk, kefir, sour cream

Milk is graded according to what?

Its bacteria count | Highest grade = lowest bacteria count

Who grades milk?

USDA

Milk products crossing state lines must be what?

Pasteurized

Differentiate condensed and evaporated milk.

Both are evaporated milks. | Condensed has ALOT of sugar

Name 6 benefits of milk.

Bone health 2. Weight management 3. Probiotics for gut microbiota health 4. Heart health 5. Protective against colorectal cancer 6. Source of conjugated linoleic acid -> isomer of linoleic acid

What are the benefits of CLA?

1. Anti-carcinogenic properties | 2. Anti-atherogenic

Explain the composition of active cultured yogurt.

Don't heat the yogurt before packaging | fermentation process continues, so microorganisms are still alive when you digest them

What's the difference between greek yogurt and regular yogurt?

Strain the yogurt more, so more whey is put aside, which makes it very rich in fat and protein (more bang for $)

How long can milk be stored for in the fridge?

3 weeks

How long can yogurt last in the fridge?

- Eat within 10 days | - Can last up to 3-6 weeks

How long can buttermilk last in the fridge?

Use within 3-4 days | Lasts up to 3 weeks

How long does sour cream lasts in the fridge?

Use within a few days once opened

How long do nonfat dry milk lasts and sweetened condensed milk?

up to 1 year

How long does ultra-pasteurized milk lasts?

up to 3 months

True or False: in milk, denatured proteins often separate from liquid by coagulation

True

True or False: adding acid to milk will cause whey to curdle.

False, it is casein

Once dry milk products are opened, how do you treat them?

Like fresh milk