The difference between acid value and peroxide value
Because many times during oil or food testing, acid value and peroxide value are mentioned together, and people are generally concerned about the relationship between acid value and peroxide value.
What needs to be explained here is that the acid value and peroxide value are both indicators for evaluating the quality of oil, but there is no exact positive correlation between the two. We can see the difference between the two from the following aspects:
|
Item |
Acid Value |
Peroxide Value |
|
Concept |
An indicator of the degree of oil deterioration The number of milligrams of potassium hydroxide required to neutralize 1 gram of chemical. |
An indicator of the degree of oxidation of oils and fatty acids, the peroxide value is used to determine their quality and degree of deterioration. |
|
Describe object |
Acid value that can be dissociated from fats and oils in food products |
The amount of carbonyl groups in foods or fats that can be measured |
|
Connotation |
The first part of oil rancidity: the enzymatic hydrolysis process of oil, oil is directly hydrolyzed into glycerol and fatty acids. The third part of oil rancidity: peroxide is further oxidized into lower aldehydes, ketones, and acids. |
The second part of oil rancidity: the double bonds of unsaturated fatty acids in oil are oxidized and opened to form peroxides. |
During the spoilage process of food or oil, acid value and peroxide value can exist at the same time, but in the end of rancidity there will be only acid value but no peroxide value.
When the oil is an unsaturated acid, the peroxide value will appear first and then the acid value. The acid value will keep rising, while the peroxide value will rise and fall (disproportionately).
