ANSCI 201--Dairy

Mmm...nut beverages

What is the main constituent of milk (87.0%)?

Water

What is the leading solid constituent of milk (5.0%)?

Lactose

What % of milk does fat constitute?

3.8%

What % of milk do caseins constitute?

2.8%

What % of milk do albumins/globulins constitute?

0.7%

What % of milk do proteins (caseins + albumins/globulins) constitute?

3.5%

What % of milk do ash/minerals constitute?

0.7%

What % of milk do solids non-fat (SNF) constitute?

9.2%

What gives milk its flavor?

Fat

What % of calories does fat contribute to milk?

48%

How does fat exist in milk?

As a temporary emulsion with globules suspended in liquid

How heavy are fat globules?

Lightweight

What shape are fat globules?

Spherical

What is the fat globule membrane composed of? What is its charge?

Phospholipids

Slight negative charge

Which chemical component makes up the greatest % of milk lipids?

A. Triglycerides

B. Phospholipids

C. Sterols

D. Vitamins

Triglycerides

Which fat-soluble vitamins are present in milk lipids?

A, D, E, and K

What does vitamin A help with?

Vision

What does vitamin D help with? ☼

Calcium absorption

What does vitamin E help with?

Immunity

What does vitamin K help with?

Blood clotting

What is a triglyceride made of?

1 glycerol and 3 fatty acids

Why are phospholipids good emusifying agents?

Half is soluble in water, half is soluble in fat

What does this structure represent?

A fatty acid

Are saturated fatty acids solids or liquids?

Solids

Do saturated fatty acids contain double bonds between carbon atoms?

No

Are unsaturated fatty acids solids or liquids?

Liquids

Do unsaturated fatty acids contain double bonds between carbon atoms?

Yes

What % of fatty acids in milk fat are saturated?

hint: they’re evil

66%

What % of fatty acids in milk fat are unsaturated?

34%

Does milk have a high % of short-chain acids or long-chain acids compared to other animal products?

Short-chain

Why does cream rise to the top?

Fat has a lower specific gravity than milk

What kind of solution does lactose form?

True molecular solution

Milk proteins are very high quality and are only second to protein from which food?

Eggs

Lactose is a dissacharide and is made of which two monosaccharides?

Glucose and galactose

Lactose is _________ soluble and _________ sweet than sucrose.

Less

What % of calories in whole milk does protein account for?

22%

What % of solids non-fat in whole milk does protein account for?

38%

What kind of solution does protein in milk exist in?

Colloidal dispersion

What is this?

Amino acid

What kind of bond is this?

Peptide

What are the two types of milk proteins?

Caseins and whey proteins

What are the two whey proteins?

Lactalbumin and lactoglobulin

Surplus of which amino acid in milk helps offset deficiencies found in cereal proteins?

Lysine

Which milk protein accounts for 82% of total milk protein?

Caseins

Caseins are contained as what structure?

Micelles

Which milk protein accounts for 18% of total milk protein?

Whey proteins

Whey proteins contain which important substance that provides immunity?

Immunoglobulins

The enzymes rennin and pepsin result in which type of curd (hard/soft)?

Hard

Acids result in which type of curd (hard/soft)?

Soft

What makes sweet whey sweet?

Lactose

Rennin and pepsin bind with which ions?

Calcium

Rennin converts casein to what structure?

Calcium paracaseinate

Which pH results in the formation of a soft curd?

4.67

Do soft curds contain more or less minerals than hard curd?

Less

An equal number of _________ combine during acidic curd formation.

Positive and negative charges

What % of cheese is hard?

80

What are some examples of soft curd cheese?

Cottage cheese, cream cheese, and ricotta cheese

What is ash in relation to milk?

Minerals

What kind of solution does ash exist in?

True solution

What is the leading mineral present in ash?

Potassium (K)

Which minerals is ash a good source of?

K, Ca, S, P, Mg, Cl, Zn, Se

Which minerals is ash not a good source of?

Fe, Cu, Mn, Na

What role does ash play in human health?

Prevents osteoporosis through Ca and Vitamin D

What are the organic catalysts present in milk?

Vitamins

Which milk vitamins are fat soluble?

A, D, E, and K

Which milk vitamins are water soluble?

B and C

Yellow color in milk produced by Guernsey and Jersey cows is due to what pigment?

Carotene (precursor of vitamin A)

Which two vitamins are usually fortified during milk processing?

A and D

What is the major enzyme found in milk?

Lipase

Should leukocytes be present in high or low levels in milk?

Low

What minor constituent of milk are essentially the cow’s body cells?

Somatic cells

Do seals and polar bears have a high or low % fat in their milk to provide their young with energy?

High

What does a lactation curve look like?

What is the first secretion from the mammary gland after birth called?

Colostrum

Colostrum contains a high % of which two proteins?

Albumin and globulin

As the stage of milking progresses, what happens to the % fat of milk?

Increases

What are some factors that can affect milk composition?

• Nutrition

• Disease

• Genetics

• Season of year

• Age

What is the word for something that appeals to the senses?

Organoleptic

What is the most favorable milk flavor?

Bland and slightly sweet

What milk flavor does an absorbed defect produce?

Feedy, cowy, barny

What allows for milk to absorb flavor from the cow’s food?

High blood flow between the mammary gland and milk

What are some ways to prevent milk from absorbing flavor?

• Don’t feed animals aromatic feeds near milking time

• At home, keep milk away from aromatic items in fridge

What milk flavor does a bacterial defect produce?

Acidic, putrid, malty

What are the causes of a bacterial milk defect?

Improper cooling and poor sanitation

What is the flavor of a chemical milk defect?

Papery/cardboardy

What is the cause of chemical milk defects?

Oxidation of unsaturated fatty acids

What are the catalysts of chemical milk defects?

Copper, iron, and UV light

How can we prevent chemical milk defects?

Stainless steel equipment, proper packaging and storage

What is another term for chemical milk defects?

Oxidative rancidity

What is the flavor of hydrolytic rancidity milk?

Bitter and soapy

What is the cause of hydrolytic rancidity of milk?

Enzymatic hydrolysis of triglycerides by lipase

How can we prevent hydrolytic rancidity of milk?

Proper handling and storage, avoiding excess agitation and stirring, pasteurization

What is the process by which additional skim milk is added to milk to achieve the desired fat content?

Standardization

What will happen to you if you add water to milk?

Death

What is the process by which milk is heated to kill pathogenic bacteria?

Pasteurization

What is the process by which milk is heated at 145 degrees for 30 minutes?

LTLT (low temp long time) pasteurization

What is the process by which milk is heated at 161 degrees for 15 seconds?

HTST (high temp short time) pasteurization

What is the process by which milk is heated at 280 degrees for 2 seconds?

UHT (ultra high temp) pasteurization

What is is the process by which humans are heated at 280 degrees for 2 seconds?

Arson

What is the process that reduces the size of fat globules so that the milk fat doesn’t separate in the milk fluids?

Homogenization