Minyak Jelantah, or used cooking oil that has a blackish-brown colour should no longer be used for frying food. However, in everyday life, using used cooking oil is still common.
To save on expenses, many people still use cooking oil for cooking. For the same reason, food vendors, especially fried foods sold on the streets, often use this oil.
In fact, according to the professor of IPB University, Prof. Dr. Ir. Sedarnawati Yasni, M. Agr, a senior auditor at LPPOM MUI, consuming used cooking oil has dangerous health risks. Using oil repeatedly by heating will cause most of its contents to be damaged, and carcinogenic compounds will be formed. For example, heating used cooking oil repeatedly at high temperatures (higher than the range 170oC – 200oC ) will cause an oxidation process so that the unsaturated fat content of the cis structurewill change to a trans structure, and the formation of peroxides and hydroperoxides will also occur which is a free radical.
In detail, it can be explained that used cooking oil can be a medium for absorbing free radicals, which will also be absorbed into fried foods. Then the food enters the body, and free radical compounds will slowly oxidize the cells in the body’s organs. These substances will be cancer-causing carcinogens. Therefore, cooking oil can cause cancer deposition of fat in blood vessels, and the aftermath can reduce intelligence. Excessive consumption of fried food products using used cooking oil can lead to overweight or obesity which can cause serious complications, such as diabetes and heart disease.
Cooking oil, used many times, is also a breeding ground for various bacteria. Bacteria will live and develop by eating the remaining fried crumbs that settle in used cooking oil or stick to the frying pan so that they can become a source of disease due to bacterial infection.
According to research by experts from the University of the Basque Country in Spain, used cooking oil contains organic aldehyde compounds, which can turn into carcinogens in the human body and turn, can trigger degenerative diseases, such as heart disease, Alzheimer’s disease, and Parkinson’s disease.
Pay Attention to the Halal Product
Cooking oil, a basic need for public consumption can come from refined plant or animal fats. Cooking oil from vegetable ingredients can come from coconut plants, seeds, nuts, corn and soybeans. Generally, vegetable cooking oils contain saturated fatty acids (including octanoic, decanoic, lauric, myristic, palmitic and stearate) and unsaturated fatty acids (such as oleic, linoleic and linolenic).
The process of frying with oil can be considered more efficient than the process of roasting and boiling. In addition, the frying process can improve taste, nutritional content and durability and increase the caloric value of foodstuffs. In the frying process, oxygen can oxidize oil quickly. Fat damage during frying can be caused by oil contact with air, excessive heating, oil contact with food, and burnt particles. Oil damage due to heating can be seen from colour changes, increase in viscosity, increase in free fatty acid content, increase in peroxide and decrease in iodine number.
Oil damage will affect the quality, nutritional value, and appearance of fried foodstuffs. Therefore, using used cooking oil purifier will benefit industries that use it in their production process. The process of refining used cooking oil can use ‘bleaching earth’. However, it produces low oil quality because beta-carotene and vitamin E compounds are adsorbed and require relatively high temperatures (100-120o C). Natural material adsorbents, such as plants and wood, can be used to avoid this. Generally, raw material adsorbents are leftover materials (a process) that do not have an economical price and often cannot be reused for an operation.
Adsorbents are solid substances that can absorb fluid particles in an adsorption process. The adsorption process is a physical phenomenon that occurs when gas or liquid molecules come into contact with a solid surface, and some molecules condense on the concrete surface. Adsorbents are specific and made of porous materials—for example, bagasse, peanut shells, pineapple leaves, corn cobs, and sawdust. The widely used adsorbent generally comes from agricultural waste, which is processed into activated charcoal and applied as an adsorbent. The content of carbon compounds, namely cellulose and hemicellulose, contained in this type of adsorbent acts as a clarifier for used cooking oil.
Making activated charcoal can be done, namely agricultural waste material that has been burned, finely ground, filtered to obtain a relatively small powder/charcoal size, and then mixed with starch as an adhesive/binder for the fine granules of the charcoal so that it does not dissolve in used cooking oil, then Bake until dry and light.
The quality of used cooking oil purifiers is relatively better, but paying attention to the halal aspect is necessary. According to Prof. Sedarnawati, currently, there is a lot of halal-certified cooking oil, but if the cooking oil is used for frying food that is not halal, then the used cooking oil becomes haram. The risk of consuming non-halal used cooking oil is higher when people buy fried food from food vendors still needs to be halal certified. Traders of this type generally use used cooking oil purchased from restaurants directly or very refining it before use.
Based on Prof. Sedarnawati’s observations, with several fried rice sellers going around, the used cooking oil smelled of fried chicken. It was suspected that the seller got the used cooking oil from a fried chicken restaurant. To ensure the halalness of used cooking oil, it is necessary to know whether the chicken being fried has gone through a halal slaughter process and whether the cooking oil used is halal certified. Furthermore, in refining used cooking oil, it is necessary to consider the purification method and the type of adsorbent used.
By paying attention to the health and halal aspects of used cooking oil, Prof. Sedarnawati reminded people to be wiser in choosing and using cooking oil.
There are several things to watch out for:
- Make sure that the cooking oil purchased is halal-certified.
- Don’t use cooking oil for frying repeatedly. Maximum use is enough two to three times the frying while observing the colour changes.
- Avoid buying used cooking oil whose source is unclear cause the potential for mixing it with haram ingredients is very high.
- If you want fried food, ensure that the seller uses halal-certified cooking oil, not used cooking oil.
Some tips for paying attention to other signs: a) not having good clarity; b) if it is filtered, there are still leftover particles/fried crumbs; c) smelling the residual aroma of the fried ingredients; and d) oil easily smokes when used. (FM)
* Hidayati, FC, Masturi, Yulianti, I. 2016. Purification of Used Cooking Oil (WED) Using Corncob Charcoal Journal of Physics Education, Vol. 1 No. 2 : 67-70