Effect of Heat and Oxygen on Fats and Oils

Introduction

• Fats and oils are commonly found in many foods and are composed of triglycerides, a special group of esters. Understanding how cooking, heat, and oxygen affect these fats and oils is essential for maintaining food quality.

Hydrolysis during Cooking

• Edible oils are non-polar and not soluble in water.
• During cooking, edible oils can undergo hydrolysis, breaking the ester link in triglycerides and producing glycerol and three fatty acids as products.

Solubility of Glycerol and Fatty Acids

• Glycerol, produced by the hydrolysis of fats or oils, contains three hydroxyl groups, allowing it to form hydrogen bonds and become soluble in water.
• Fatty acids produced during hydrolysis have a polar carboxyl group, making them partially soluble in water.
• However, the presence of non-polar hydrocarbon tails in fatty acids can render the entire molecule insoluble in water, with longer hydrocarbon tails resulting in decreased solubility.

Further Reactions of Fatty Acids

• Fatty acids formed by hydrolysis may undergo additional reactions with other compounds in food, such as neutralisation with alkaline compounds.

Oxidation in the Presence of Oxygen

• Fats and oils can also be oxidised when exposed to air (oxygen), leading to the development of rancidity.
• Oxidation reactions in fats and oils can negatively impact food quality and taste.

Conclusion

• The cooking process can cause the hydrolysis of fats and oils, leading to the production of glycerol and fatty acids. Glycerol and certain fatty acids

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Effect of Heat and Oxygen on Fats and Oils

Conclusion

• The cooking process can cause the hydrolysis of fats and oils, leading to the production of glycerol and fatty acids. Glycerol and certain fatty acids can be soluble in water due to their polar properties, although the length of hydrocarbon tails affects solubility. Additionally, fats and oils are susceptible to oxidation when exposed to oxygen, resulting in rancidity and deterioration of food quality.