Week 6

Question 1

Shorthand chemical notation

Answer 1

Shorthand is where you describe the monomer unit with the first three letters. Then, if the sugar unit is in D formation that information is omitted, but if it is in L configuration, that is included. Next the size of the ring is included with an f or a p for furanose or pyranose. The anomeric configuration is designated at the beginning of the monomer with an a or b for alpha or beta. Finally, if the compound is a uronic acid, an A is placed at the end of it. The carbons of which it bonds are also indicated after. Example: BGalp(1-4)Glc for lactose

Question 2

Uronic acid

Answer 2

Uronic acids are sugar which have their CH2OH groups oxidized to form a carboxylic acid.

Question 3

Thixotropic

Answer 3

This is a property of a polysaccharide where as shear is added, the viscosity slowly declines. This is a time sensitive process because it takes longer for the hydrogen bonds to break and allow the chains to align themselves with the shear thus reducing viscosity. It also takes time for the viscosity to increase. An example of this would be an additive to cake mix which would allow it to be mixed but not splatter everywhere as you mix it. Can have a slimy mouthfeel

Question 4

Psuedoplastic

Answer 4

This is a property of polysaccharides where the viscosity of a solution decreases sharply as shear is added and reforms quickly when the shear stops. An example of this is ketchup which becomes more liquid or less viscous as you shake and pour it, but when the movement stops it becomes for firm again. Not slimy

Question 5

Random coil

Answer 5

A random coil occur when there are no or irregular charges/branches to keep the chain from bending up on itself. This creates a random bunch as a tertiary structure

Question 6

Extended rod

Answer 6

An extended rod occurs when there are charges and branches that keep the chain from folding up on itself. the charges, negative, repel each other. If the chain is fully saturated in charges or branches, then it wont interact with itself or anything else and will not be soluble like with cellulose.

Question 7

Branch-on-branch

Answer 7

Amylopectin has a branch on branch structure where there are branches of saccharide units on branches from the original chain. This highly branched structure lends itself to high molecular weight.

Question 8

Chain entanglement

Answer 8

When this happens, viscosity increases. The chains also have to have irregular charges and and branches that would allow it to interact with other chains.

Question 9

Chain domain

Answer 9

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Question 10

Overlap concentration

Answer 10

this describes how much chain overlap in a solution.

Question 11

Flow behavior

Answer 11

This is determined by the size, shape, flexibility, and presence of charges. The way that the polysaccharide behaves under shear is either pseudoplastic or thixotropic.

Question 12

Mouthfeel

Answer 12

A polysaccharide that is thick, coats the mouth and is difficult to swallow is said to be slimy. This is like with thixotropic which slowly becomes less viscous with shear. Inversely, a solution that becomes less thick with shear is not slimy.

Question 13

Stabilizer

Answer 13

This relates to making a product shelf stable. This can like with gum Arabic which acts an emulsifier which can stabilize the colloidal dispersion it is in. A polysaccharide with controlled junction zones can prevents syneresis

Question 14

Body/bulking agent

Answer 14

polysaccharides can also act as fiber, being a filler.