Effects of repeated heating of cooking oil on human health

1. Effects of repeated heating of cooking oil on human health Presented by Noor Imran F2019321071

2. Presentation overview • Cooking oil • Types of cooking oil • Cause of repeated heating of cooking oil • What happens when oil is reheated? • Changes in cooking oil when heated repeatedly • Effect on human health • Methods suggested to reduce the harmful effects • Conclusion

3. Cooking oil • Cooking oil is plant, animal, or synthetic fat used in frying, baking, and other types of cooking • Cooking oil is typically a liquid at room temperature

4. Types of cooking oil • Coconut oil • Olive oil • Avocado oil • Sunflower seed oil • Pumpkin seed oil • Peanut oil • Seasame oil • Flaxseed oil

5. Cause of repeated heating of cooking oil • In developing countries consumption of ready-made food is in much demand • Edible vegetable oil is the major ingredient in fried food products • Therefore, the cost of the oil becomes the most important factor to be considered in terms of economy • As a result, vegetable oil is often heated repeatedly to ensure cost effectiveness

6. What happens when oil is reheated? • Reheating changes the chemical composition of oil, and apart from producing harmful substances that can cause complications • It becomes rancid • The oil results in bad taste and give off a pungent odor

7. Chemical changes during reheating of cooking oil • During deep-frying of food at temperatures between 170° – 200°C, the oil used undergo following changes: • Hydrolysis • Oxidation • Polymerization

8. Changes in physical appearance • When heated repeatedly, changes in physical appearance of the oil will occur such as: • Increased viscosity • Darkening in color

9. Effect on human health • Repeated heating of oil accelerates oxidative degradation of lipids forming hazardous reactive oxygen species and depleting the natural antioxidant contents of the cooking oil • Lipid oxidation causes a high risk for the development of coronary heart diseases

10. Effect on human health • Long-term ingestion of food prepared using reheated oil can cause pathologies such as: • Hypertension • Diabetes • Vascular inflammation

11. Effect on human health The human body is subjected to a significant oxidative stress as a result of the misbalance between anti oxidative protective systems and the formation of strong oxidizing substances, including free radicals • This stress can damage DNA, proteins, lipids and carbohydrates and could cause negative effect to intracellular signal transmission

12. Cont.. Reheated vegetable oil Nitric oxide inactivation Production of free radicals Reduced vasorelaxation Oxidative stress Endothelial dysfunction Cardiovascular diseases

13. Methods suggested to reduce the harmful effects The use of natural antioxidants in cooking oil as adsorbents can make the oil safe by retarding the formation of oil deterioration products which slow down the oxidation of oil at room temperature ▪Tocopherols ▪Butylated hydroxy anisole (BHA) ▪Butylated hydroxy toluene (BHT) ▪Propyl gallate (PG) ▪Tertbutyl hydroquinone (TBHQ)

14. Methods suggested to reduce harmful effects • Addition of different antioxidants like sugarcane bagasse, rosemary extract, turmeric extract etc. • Oil deterioration can also be reduced by taking blended oil or an oil mixture of different types with varying concentration of the different oils mixed.

15. Turmeric extract as an antioxidant • Addition of Curcumin, a natural antioxidant present in Turmeric can reduce the harmful effects of oil deterioration products • Decrease trans fatty acid content • inhibit the auto-oxidation rate • Modify lipid radical into more stable form, that commonly inhibit the fat oxidation reaction

16. Conclusion • Edible oil becomes highly viscous and presence of harmful products increases when oil is heated repeatedly • This oil has become dangerous for human consumption • Oil should not be heated again and again and the formation of harmful products can be minimized by discarding it (for making soap at small scale) or using it with certain antioxidants