Protein lecture 5

Question 1

Emulsification

Answer 1

Triple layered milk globules are destroyed in water and these milk particles are dispersed into multiple particles. The globule is then stabalized by casien and whey protein.

Question 2

Creaming:
Sedimentation
Floculation
OSwald forces

Answer 2

Oswald forces- larger bubbles form in the expense of small ones
Sedimentation-the drag force brings particles to the bottom of the container
Floculation-particles begin to clump togehter in chunks.
Creaming: Particles are pushed by a boyant force over the drag force based on their veolcity to the top of a fluid.

Question 3

Foaming

Answer 3

water bubbles and air mix with one another and an interface between them exists. IF you go above the liquid state you will reach a phase where a polyhedral structure is formed and polyhedral structures are closely packed together with little liquid between them. Foam bubbles are made of air seperated by surfactant or protein networks form water

Question 4

Dispproportion in gas bubbles:

Answer 4

initially there is a high concentration of co2 gas around small bubbles and which diffuses into the low concentrations around large bubbles. These concentrations of co2 become very saturated and end up merging into large bubbles forming even larger bubbles which accumulate at the top of the foam

Question 5

Protein variability

Answer 5

proteins incorporated into solutions have different foaming capacities depending upon the degree to which the volume of gas (amt. of gas) compares to the volume of liquid (amt. of liquid).

Question 6

Factors influencing stabalized foams

Answer 6

-Solution pH
-foam is more stable at pI
Salt con.
-greater salt con. more foaming
-Ca2+ and mg2+ form crosslinks with one another
-

Question 7

Surface pressure

Answer 7

The amount of pressure experienced by particles at the surface which is inversly proportional to surface energy. The more proteins that bind to molecules at the surface interface the lower the surface pressure.

Question 8

Protein interactions with molecules:

Answer 8

Proteins interact with molecules by containing enough hydrophobic surfaces to bind, denature and anchor to surface particles. They are able to expose their nonpolar side chains to the nonpolar environment and are able to express their entropies at a lower energy.