1. Proteins
Milk and Dairy

2. Proteins
Most abundant molecule in cells making up 50% or more of their dry weight
Every protein has a unique structure, or shape
Allows it to perform a specific function
Enzymes are proteins that function as catalysts for many reactions in foods
Contains oxygen, hydrogen, carbon, nitrogen
Most also contain sulfur
May also contain: phosphorus, iron, copper, zinc
Very important nutritionally and functionally in foods

3. Proteins Alanine Phenylalanine Glutamic acid
Polymers of amino acids (set of 20)
Some water soluble, some not
Some charged, some not
Sequence programmed by DNA for a purpose
Alanine
Phenylalanine
Glutamic acid

4. Protein Folding Water hating (hydrophobic) amino acids
The hydrophobic groups are concealed in the protein core by spontaneous, natural folding
Peptide chain

5. Proteins Primary sequence of amino acids Secondary - local folding
Tertiary - large scale folding
Quaternary - association structures
Computer model of b-lactoglobulin, an important milk serum protein

6. KVFGRCELAAAMKRHGLDNYRGYSLGNWVCAAKFESNFNTQATN RNTDGSTDYGILQIN
Lysozyme
KVFGRCELAAAMKRHGLDNYRGYSLGNWVCAAKFESNFNTQATN RNTDGSTDYGILQIN
“Lysozyme reaction is hydrolysis of the beta (1-4) glycosidic bond between N-acetylglucosamine sugar (NAG) and N-acetylmuramic acid sugar (NAM).”

7. Protein Denaturation
Abrupt change in protein structure on being moved from non- native conditions (heat, acid, intense mixing, solvents)
Sometimes (rarely) reversible
Enzymes no longer work
Texture may change
Image: Flickr user ClickFlashPhotos / Nicki Varkevisser

8. Enzymes http://www.youtube.com/watch?v=XTUm-75-PL4
Enzymes are proteins but catalyze reactions with protein and non-protein substances
Each enzyme has a unique structure which enables it to attach to specific substrates and catalyze reactions
When the reaction is complete the enzyme is released an able to act as a catalyst again
How might enzymes help in food processing? How might they be a problem in food processing?

9. Isoelectric Point The pH at which a protein is electrically neutral
Does not mean there are no charged groups
It means the number of positive charges is equal to the number of negative charges
The point at which the protein molecules precipitate
Molecule that carry a like charge repel each other
Removal of the charge allows them to interact with each other

10. General composition of milk
Component
COW
GOAT
SHEEP
Water
87.3
87.6
60.7
Lactose
4.8
4.5
Fat
3.7
3.6
7.4
Protein (casein + whey)
3.4
3.5
Salts (minerals)
0.7
0.8
1.0

45. Mozzarella Heaven!

57. Cheese in the Sous Vide

60. NATURAL VS. PROCESSED CHEESE
...know what you're buying.
Natural cheeses are made by the traditional methods. Processed cheese is natural cheese that has been ground, mixed, and pasteurized. The heat applied during this process halts the “aging” of the cheese, extending the shelf life and stabilizing flavor changes. Emulsifiers have been added to prevent the separation of fat, producing desirable slicing and melting qualities in the final product. The processed cheese has a slightly different taste and appearance than the natural cheese. For example, natural Swiss cheese has holes in it... processed Swiss cheese doesn’t Natural cheese is usually more expensive than processed cheese.
Natural
vs.
Processed
Swiss