Analytical methods of TG

Question 1

What are the 4 analytical methods seen in class?

Answer 1

1. saponification value
2. iodine value
3. gas chromatographic analysis
4. liquid chromatography

Question 2

What is the iodine value?

Answer 2

mass of iodine in grams absorbed by 100 g of the sample.

Question 3

What does the iodine value represent ?

Answer 3

the degree of unsaturation of a molecule

Question 4

The iodine value of a fat sample is : A. Directly proportional to the chain length of fatty acids in the sample
B. Inversely proportional to the chain length of fatty acids in the sample
C. Directly proportional to the number of double bounds in the sample
D. Inversely proportional to the number of double bonds in the sample

Answer 4

C

Question 5

What is the saponification value?

Answer 5

number of milligrams (mg) of potassium hydroxide (KOH) required to neutralize all fatty acids resulting from the complete hydrolysis of 1 g of the sample.

Question 6

The saponification value of a fat sample is ____ to the number of fatty acids in the sample

Answer 6

directly proportional

Question 7

The saponification value of a fat sample is _____ to the chain length of fatty acids in the sample

Answer 7

Inversely proportional

Question 8

Interesterified TGs can be fractionated by controlling the:

Answer 8

temp

Question 9

The rate of the hydrogenation reaction is measured by the change of:
A. Saponification value per minute
B. Chain length per minute
C. Iodine value per minute

Answer 9

A. Saponification value per minute

Question 10

What is the formula of the saponification value?

Answer 10

Saponification value = 56.1 × (B – S) × normality of HCl / g of sample

Question 11

Would the saponification value of monoglyceride be lower or higher than TG

Answer 11

lower

Question 12

What is the formula of the saponification value

Answer 12

saponification value = 168000/MWTG

Question 13

What are the steps for the GC analysis?

Answer 13

1. Extract fat.
2. Saponify (hydrolysis under basic condition).
3. Preparemethyl esters (CH3ONa).
4. Chromatograph methyl esters.
5. Determine peak areas of fatty acids.
   Fatty acids are identified by retention time.
6. Compare with response curve of fatty acid standards.

Question 14

What is the difference in the FA distribution on the TG of the natural lard vs the rearanged lard

Answer 14

Natural lard (palmitic acid at 2 position is 64%) ß-crystal (OPS)
Rearranged lard (palmitic acid at 2 position is 24%) ß'-crystal (POS)