To understand the concept of rancidity in fixed oils and how it affects different values, we need to dive into the chemistry of oils:
- Rancidity: This is the process where oils undergo degradation due to exposure to oxygen, light, or moisture, leading to a sour taste and unpleasant odor.
- Acid Value: It measures the amount of free fatty acids present in the oil. As oils become rancid, the triglycerides can break down into free fatty acids, which raises the acid value.
Now, let's evaluate the options provided:
- Higher Iodine value as compared to the standards: The iodine value indicates the degree of unsaturation. It doesn't necessarily correlate directly with rancidity, as rancidity primarily involves oxidation, rather than the degree of unsaturation.
- Higher Acid value as compared to the standards: As explained above, rancidity results in the breakdown of triglycerides, increasing the amount of free fatty acids and, consequently, the acid value.
- Higher Peroxide value as compared to the standards: While the peroxide value measures oxidation, indicating early stages of rancidity, it's not the best measure compared to acid value, which continues to increase as rancidity progresses.
- Higher level of Unsaponifiable matter: This refers to substances in the oil that cannot form soap. It normally does not change substantially with rancidity.
Based on the reasoning above, the correct answer is that rancidity in fixed oils generally shows a Higher Acid value as compared to the standards. This is due to the accumulation of free fatty acids as the oil breaks down.