Question

Differentiate between Hydrolytic and oxidative rancidity.

Answer 1

Hint:Both are two different types of rancidity. One occurs by breakdown of triglycerides and elimination of free fatty acids. While the other one is caused by oxidation of the unsaturated fatty acid chains of lipids by oxygen present in the atmosphere.

Complete answer:
To answer this question, we have to know about the hydrolytic and oxidative rancidity. Hydrolytic rancidity is the odor that occurs when triglycerides are parted and free fatty acids are discharged. This reaction of lipids with water may need a catalyst, resulting in the production of glycerol and free fatty acids.
Oxidative rancidity in edibles products is recognized as the perception of objectionable flavours and odours result of oxidation of the unsaturated fatty acid chains of lipids by environmental oxygen. Because of the 'spontaneous' type of the reaction the overall method is known as autoxidation.

Hydrolytic rancidity	Oxidative rancidity
Occurs more rapidly in the presence of enzymes such as lipase, and with heat and moisture.	The process begins by a free radical mechanism catalysed by light in the availability of metal ions or enzymes.
The water available in the food and high temperature will raise the range of break down to fatty acids.	The complex free radical reactions will form a many different products, most of that have disagreeable odour or tastes.
The free fatty acids have an unpleasant smell giving a rancid smell and taste to milk and butter that have been stored for too long. Extended chain acids are not much volatile, so the smell is rarely recognized.	In extremely unsaturated lipids like odour fish oils, oxidative rancidity can be a main issue.

Note: Hydrolytic rancidity is the result of the hydrolysis of fats with the liberation of one or more volatile fatty acids, whereas in oxidative rancidity the unsaturated fatty acid fragments of glycerides are oxidized at their double bonds with the ultimate formation of ketones, aldehydes and acids.