The smell of rancid oil

People are now becoming more and more particular about food, not only vegetables and fruits, but also some commonly used condiments. Many condiments have been exposed to have some problems, such as the oils that people eat every day, so people are extra careful when purchasing these foods. Sometimes people may find that cooking oil has a rancid smell. What harm does rancid oil have to the human body?

1. Why does cooking oil go bad?

One is that the raw material residues contained in the oil are decomposed by enzymes produced by microorganisms; the other is that the edible oil is hydrolyzed under the action of sunlight, air, temperature or trace metal ions. After the decomposition of fats, many unsaturated fatty acids are released. This unsaturated fatty acid is easily oxidized to produce aldehydes, ketones and other oxides that are harmful to the human body. It is these substances that cause the rancid smell of fat.

2. Hazards to Human Health

When oil deteriorates, the linolenic acid, linoleic acid and vitamin E contained in it are also destroyed. Not only that, rancid oil can also destroy the vitamins in other foods. If you eat a lot of this oil at one time or consume it in small amounts for a long time, poisoning will occur.

①Adverse reactions in the digestive tract. Generally, dizziness, headache, abdominal discomfort, nausea, vomiting, abdominal distension, diarrhea, etc. will appear after 2-3 hours. In severe cases, high fever may occur.

②Disrupt blood circulation. The lipid peroxides produced during the rancidity process of oils can cause cerebral thrombosis and hemolysis, and damage the blood circulation system.

③Leading to the formation of cancer cells. The malondialdehyde contained in spoiled cooking oil can react with proteins and deoxyribonucleic acid in the human body, making the protein structure hard and leading to the formation of cancer cells.

④Promote aging. Oils and high-fat foods (such as cured meats, ham, biscuits, dried fish, etc.) are easily oxidized after being stored for a long time, especially when exposed to sunlight and heat, and produce ketones, aldehydes, etc., and develop a sour smell. These poisons can destroy enzyme systems and vitamins in the human body, affect the normal formation of deoxyribonucleic acid, and lead to aging of the body.

3. Methods for treating deteriorated oil

If the cooking oil stored at home has a slight rancid smell, it can be processed before consumption. The method of dealing with it is to pour oil into the pot, heat it until it is hot, add a certain amount of alkaline noodles, and stir slowly with chopsticks. The oil will first become turbid, and then cotton-like saponified substances will slowly precipitate out. At this time, stirring should be slow. After the oil cools down a little, filter it with filter paper to remove the saponified substances in the oil.

4. Correct way to store edible oil

①Vegetable oil. Do not use plastic buckets or metal containers for oil. You can use a ceramic jar or a dark-colored, small-mouthed glass bottle. Before filling the oil, the container should be washed and wiped dry. After filling the oil, cover it tightly and store it in a cool, dry and dark place. If it needs to be stored for a longer time, you can add antioxidant vitamin E. Add 1 vitamin E capsule to 500 grams of cooking oil (puncture the capsule and squeeze it into the oil) and shake well. It is effective in controlling the rancidity and deterioration of cooking oil. Do not mix used cooked oil with raw oil.

②Animal oil. When refining oil, you can refine it for a longer time to minimize the moisture in the oil and remove all the oil residue. Before the oil solidifies, add an appropriate amount of salt, stir evenly, put it into a porcelain jar, cover it and seal it, and place it in a cool place. After the oil is refined, adding some pepper, cloves, aniseed, cinnamon, ginger, etc. also has a certain antioxidant effect. If you don’t finish using the oil, you can boil it again after a period of time to extend its storage time.