Question

Thermal stability. If you’ve ever put something into a pan of hot oil or watched the basket of fries being lowered in a fast food restaurant, you know what happens next. If you don’t get rid of excess moisture on the food you cook in oil, what happens? What happens to those fries when they are lowered into the hot oil? What about the molecular structure of oils makes them ideal for this kind of cooking (at least 2 reasons)?

Answer 1

If we put something say some kind of vegetables i.e. potatoes into a frying pan containing hot cooking oil

at temperature 120°c or more than that, will tend to light brown due to the accumulation of non-volatile decomposition products like free fatty acids, oxidized triacylglycerols. Some of the fatty acids might get burned and convert into small coloring particles. Heating causes some chemical reactions in the oil such as oxidation, hydrolysis and polymerisation.

If excess amount of moisture is remained, the fries will make a crackling sound when dipped it in a hot oil.

Because, water is suddenly vapourized and fries may get burned.

The molecular structure of oils makes them for this type of cooking are in the picture given below-