Why Do We Use Cooking Oil When Cooking?

Cooking with Fats and Oil

If you frequently cook in the kitchen then you are probably familiar with using oil. Oil is used as an ingredient and is also used for frying. One of the most common cooking oils is vegetable oil, but do you really know what that is? Do you know what oils are best used for frying and why do we use it?

Cooking oil is plant, animal, or synthetic fat used in frying, baking, and other types of cooking. It is also used in food preparation and flavouring that doesn't involve heat, such as salad dressings and bread dips, and in this sense might be more accurately termed edible oil.

Cooking oil is typically a liquid, although some oils that contain saturated fat, such as coconut oil, palm oil and palm kernel oil, are solid at room temperature.

Types of cooking oil include: olive oil, palm oil, soybean oil, canola oil (rapeseed oil), pumpkin seed oil, corn oil, sunflower oil, safflower oil, peanut oil, grape seed oil, sesame oil, argan oil, rice bran oil and other vegetable oils, as well as animal-based oils like butter and lard.

Fats and oils have a range of cooking and baking applications. 

(1) First and foremost, fats and oils provide flavor. They contain certain compounds that impart specific flavors and coat the tongue, which permits flavors to linger and interact with other flavors. In the absence of fats and oils (as in some reduced-fat products), flavor may be lacking.

(2) Fats and oils affect appearance. They can make foods look moist and shiny, milk look opaque and baked goods look golden. This is because milk fat refracts light and fats and oils aid in the browning process.

(3) Fats and oils improve texture. They add their own richness and improve mouthfeel.

(4) Fats and oils help to tenderize baked goods by hindering gluten formation, which leads to flakier and more tender products. 

(5) They create emulsions, which contribute to the creaminess of dressings, frozen desserts and sauces. 

(6) Fats and oils also help to provide crispiness at high temperatures. They accomplish this by drying out food surfaces while retaining moistness.

Despite their essential functions in cooking and baking, fats and oils are concentrated sources of calories. They contain twice the calories per gram of carbohydrates or proteins (9 calories per gram in fats and oils compared to 4 calories per gram in carbohydrates or protein). One may still be able to achieve the benefits of fats and oils in cooking and baking by lightening up and using less.


How to Choose the Right Cooking Oil?

Choose cooking oils and fat with low saturated fat and a good mix of mono and poly unsaturated fats. On our graphs look for less red (saturated) and a good mix of blue and green (mono and poly unsaturated fats). 

Heating an oil changes its characteristics. Oils that are healthy at room temperature can become unhealthy when heated above certain temperatures. When choosing a cooking oil, it is important to match the oil's heat tolerance with the cooking method.

Palm oil contains more saturated fats than canola oil, corn oil, linseed oil, soybean oil, safflower oil, and sunflower oil. Therefore, palm oil can withstand the high heat of deep frying and is resistant to oxidation compared to highly unsaturated vegetable oils. Since about year 1900, palm oil has been increasingly incorporated into food by the global commercial food industry because it remains stable in deep frying or in baking at very high temperatures and for its high levels of natural antioxidants.

Oils that are suitable for high-temperature frying (above 230 °C or 446 °F) because of their high smoke point are:

• Avocado oil
• Mustard oil
• Palm oil
• Peanut oil (marketed as "groundnut oil" in the UK and India)
• Rice bran oil
• Safflower oil
• Semi-refined Sesame oil
• Semi-refined Sunflower Oil

What are the Smoking Points of Fats and Oils?

Not all fats are the same. The more refined an oil, the higher the smoke point. That's because refining removes the impurities that can cause the oil to smoke. 

Did you know that a fat is no longer good for consumption after it has exceeded its smoke point and has begun to break down?

In cooking, the smoke point of an oil or fat is the temperature at which under defined conditions enough volatile compounds are emerged from the oil that a bluish smoke becomes clearly visible. At this temperature the concentration of volatile compounds such as water, free fatty acids but also short-chain degradation products of oxidation come up from the oil. The smoke point is not giving the temperature when the oil is decomposed and possibly toxicological relevant compounds are formed.

The smoke point for an oil varies widely depending on origin and refinement. The smoke point of an oil does tend to increase as free fatty acid content decreases and degree of refinement increases. Heating oil produces free fatty acid and as heating time increases, more free fatty acids are produced, thereby decreasing smoke point. It is one reason not to use the same oil to deep fry more than twice. Intermittent frying has a markedly greater effect on oil deterioration than continuous frying. 

The following table presents smoke points of various fats:

Fat	Quality	Smoke Point
Almond oil		420°F	216°C
Avocado oil	Un-Refined, Virgin	375-400°F	190-204°C
Avocado oil	Refined	520°F	271°C
Butter		250–300°F	121–149°C
Canola oil	Expeller Press	375-450°F	190-232°C
Canola oil	High Oleic	475°F	246°C
Canola oil	Refined	400°F	204°C
Castor oil	Refined	392°F	200°C
Coconut oil	Virgin (Unrefined)	350°F	177°C
Coconut oil	Refined with stabilizers	450°F	232°C
Corn oil	Unrefined	352°F	178°C
Corn oil	Refined	450°F	232°C
Cottonseed oil		420°F	216°C
Flax seed oil	Unrefined	225°F	107°C
Ghee (Indian Clarified Butter)		485°F	252°C
Grapeseed oil		420°F	216°C
Hazelnut oil		430°F	221°C
Hemp oil		330°F	165°C
Lard		390°F	192°C
Macadamia oil		413°F	210°C
Mustard oil		489°F	254°C
Olive oil	Extra virgin	375°F	191°C
Olive oil	Virgin	391°F	199°C
Olive oil	Pomace	460°F	238°C
Olive oil	Extra light	468°F	242°C
Olive oil, high quality (low acidity)	Extra virgin	405°F	207°C
Palm oil	Difractionated	455°F	235°C
Peanut oil	Unrefined	320°F	160°C
Peanut oil	Refined	450°F	232°C
Rice bran oil		490°F	254°C
Safflower oil	Unrefined	225°F	107°C
Safflower oil	Semi-refined	320°F	160°C
Safflower oil	Refined	510°F	266°C
Sesame oil	Unrefined	350°F	177°C
Sesame oil	Semi-refined	450°F	232°C
Soybean oil	Unrefined	320°F	160°C
Soybean oil	Semi-refined	350°F	177°C
Soybean oil	Refined	460°F	238°C
Sunflower oil	Unrefined	225°F	107°C
Sunflower oil	Semi-refined	450°F	232°C
Sunflower oil	Refined	440°F	227°C
Sunflower oil, high oleic	Unrefined	320°F	160°C
Tallow (Beef)		420°F	215°C
Tea seed oil		485°F	252°C
Vegetable shortening		360°F	182°C
Walnut oil	Unrefined	320°F	160°C
Walnut oil	Semi-refined	400°F	204°C

Learn more about the food you eat at... Healthy Food Facts



References:


Bockisch, Michael. 1998. Fats and Oils Handbook. Champaign, IL: AOCS Press. pp. 95–6. ISBN 0-935315-82-9.

Fox, R. 2001. Frying oils. In Kaarin Goodburn (Ed.) EU Food Law. Woodhead. pp. 195–224. ISBN 978-1-85573-557-6.

Mozaffarian, Dariush; Katan, Martijn B.; Ascherio, Alberto; Stampfer, Meir J.; Willett, Walter C. 2006. Trans Fatty Acids and Cardiovascular Disease. New England Journal of Medicine 354 (15): 1601–113.

O'Brien, R.D. 1998. Fats and Oils: Formulating and Processing for Applications. Lancaster, PA: Technomic Publishing Co., Inc. ISBN 0-8493-1599-9.

Potter, N.N. and J.H. Hotchkiss. 1995. Food Science (Fifth ed.). New York: Chapman & Hall. pp. 359–80, 402–7. ISBN 0-442-01398-1.

The Culinary Institute of America. 1996. The New Professional Chef (6th ed.). John Wiley & Sons.