Question

The change that a lipid undergoes leading to an undesirable flavor and odour is known as

• A. Rancidity
• B. Polymerization
• C. Crystallization
• D. Saturation

Hint:

Lipid spoilage → Rancidity (unpleasant taste/smell due to oxidation).

Answer 1

The Correct Option is A

Lipid Deterioration

Lipid deterioration refers to the various processes that lead to the degradation of lipids (fats and oils), resulting in undesirable changes to their sensory (flavor, odor, color, texture), nutritional, and functional properties. In food, this is often called rancidity.

Let's examine each option:

Rancidity

Rancidity is the term used to describe the spoilage of fats and oils (lipids) that results in unpleasant odors and flavors. It's primarily caused by oxidation (reaction with oxygen) or hydrolysis (reaction with water) of the fatty acids within the lipid.

Polymerization

Polymerization is a process where small molecules (monomers) join together to form a large chain-like molecule (polymer). While it can occur in some oils under high heat, it doesn't directly cause undesirable flavor and odor in the way rancidity does.

Crystallization

Crystallization is the process by which a solid forms with an ordered atomic or molecular structure. For lipids, this refers to fats solidifying, but it doesn't inherently lead to undesirable flavor and odor.

4. Saturation

Saturation refers to the number of hydrogen atoms attached to carbon atoms in a fatty acid chain. Saturated fats have no double bonds, while unsaturated fats have one or more. This is a structural characteristic, not a spoilage process.

Why Rancidity is the Correct Answer

Rancidity specifically describes the chemical changes in lipids that lead to:

• Development of off-flavors (described as cardboardy, painty, or fishy)
• Unpleasant odors
• Potential formation of harmful compounds
• Reduction in nutritional quality

Types of Rancidity Compared

Type	Mechanism	Main Causes	Prevention
Hydrolytic	Enzyme action breaking triglycerides	Moisture, lipase enzymes	Dry storage
Oxidative	Reaction with oxygen	Light, heat, metals	Antioxidants, nitrogen packing

Practical Examples

• Oxidative rancidity: The stale taste of old potato chips
• Hydrolytic rancidity: The soapy taste of old whole grain flours
• Prevention: Vacuum packaging of nuts, adding rosemary extract to oils

Final Answer

The change that lipids undergo leading to undesirable flavor and odor is Rancidity.