Reference News Network on March 7**, Hong Kong's "South China Morning Post" recently published an article pointing out that edible oil will also deteriorate. If you cook food with spoiled oil, the taste of the food in your mouth is a nightmare. It consumes a lot of the body's stored vitamins and is associated with disease.
The article says that buying cooking oil in bulk sounds good, after all, it is the protagonist of the kitchen. But before that, keep in mind that all cooking oils, whether opened or not, will eventually go bad.
Why is this happening? A 2012 article in the Journal of Food and Drug Analysis states that the cause of deterioration of edible oil is a process called oxidation.
A reaction occurs when the unsaturated fatty acids in cooking oil meet oxygen. A previous review in the journal Frontiers in Neuroscience said that unsaturated fatty acids allow oil to remain liquid at room temperature.
According to the Centre for Food Safety of Hong Kong, oxidised cooking oil can produce unpleasant tastes and odours. A 2018 study in Nigeria warned that in addition to its poor taste, consuming spoiled oil can also produce harmful substances called free radicals in the body, which can cause cell damage.
In addition, consuming oxidized oil has been linked to diseases such as diabetes, Alzheimer's disease, and digestive issues. It also depletes the body's B and E vitamins.
Researchers said in the 2013 journal The Olive Oil Handbook that oxidation of the oil is "almost inevitable" due to the abundance of oxygen in the air around us.
In the production of edible oil, the oxidation process begins and cannot be stopped from the moment plants such as corn, peanuts, vegetable seeds and palm kernels are pressed.
Nigerian studies have shown that in addition to air, other factors such as heat, light and certain metals can also catalyze the oxidation of foods such as cooking oils.
According to an article in the journal Lipid Oxidation, exposure to light also accelerates the oxidation of oil, a process known as photooxidation. In this process, UV exposure produces free radicals that accelerate the breakdown of oil compounds, causing them to oxidize faster.
That's why cooking oil is often sold in blackout or opaque containers** to reduce the product's exposure to light.
The same article mentions that metal packaging can activate oxygen, triggering unnecessary oxidation of edible oils. This explains why some edible oil manufacturers choose glass bottles for packaging to prevent oxidation.
There are many types of cooking oils available in the market, which are made from different ingredients, and some oils are more susceptible to spoilage than others. In general, the U.S. Department of Health and Human Services recommends storing unopened olive oil and vegetable oils in a pantry or dry storage away from light for 6 to 12 months from the date of purchase. (Compiled by Wen Yi).