Question

Milk fat may be decomposed by various bacteria, yeasts, and molds, the changes that take place in the milk fat are:
A. Oxidation of the unsaturated fatty acids
B. Hydrolysis of the butterfat to fatty acids
C. Alkali production
D. Combined oxidation and hydrolysis to produce rancidity

• A. A, B and D only
• B. A, B and C only
• C. B, C and D only
• D. A, C and D only

Hint:

Remember the two main types of rancidity for fats: hydrolytic (lipolysis - requires water and lipase) and oxidative (autoxidation - requires oxygen and affects unsaturated fats). Both lead to spoilage.

Answer 1

The Correct Option is A

Step 1: Identify the fat degradation types.Milk fat (butterfat) degrades via two main chemical reactions:

Hydrolysis: Lipase enzymes (from microbial or milk sources) catalyze the breakdown of triglycerides into glycerol and free fatty acids, causing hydrolytic rancidity (statement B).
Oxidation: Unsaturated fatty acids react with oxygen, generating off-flavors and oxidative rancidity (statement A).\end{itemize}
Step 2: Assess the statements.

A. Oxidation of unsaturated fatty acids: A primary mechanism for fat breakdown.
B. Hydrolysis of butterfat into fatty acids: Another key mechanism.
C. Alkali production: Fat decomposition yields acidic fatty acids, not alkali; incorrect.
D. Combined oxidation and hydrolysis cause rancidity: Rancidity encompasses the off-flavors and odors from these decomposition pathways. Both contribute; correct.\end{itemize}Therefore, statements A, B, and D are correct.