Question

Students in this class were presented with an unknown lipid. They ran the iodine test on it, producing these results:

a. after one minute there was no fading of the color of the iodine,
b. after two minutes there was some fading of the color of the iodine
c. after 3 minutes there is no additional change in the color
d. the saturation was rated at 1.5.

What can the students reasonably conclude about this sample?
A) It is butter.
B) It is Crisco.
C) It is corn oil.
D) It is not a lipid.

Answer 1

The answer is "C. It is corn oil."

Answer 2

B). It is Crisco

Step-by-step explanation:

Iodine value can be used to measure the unsaturation (presence of double bonds in fatty acids) of oils and fats. When in solution with the presence of fats, the iodine reacts with the double bonds present and leaves the solution, which can be indirectly measured by observing the change in color (purple to colorless), the results are expressed as
`(IodineAbsorbed(g))/(100gfat)`.

A lower Iodine value indicates a high presence of saturated fatty acids, and a high value indicates a high presence of unsaturated fatty acids, which are better for nutrition.

Some typical values are:

-Fully hydrogenated fats: 1-3 (Crisco is a shortening brand, which is fully hydrogenated fat, solid at room temperature)

-Butterfat: 25-42

-Palm oil: 50-55

-Corn oil: 107-135

-Chia seed oil: 209-211