BY: Nicola Wilken
With fat being a hot topic these days, you are probably wondering if you are consuming the right type. With so many oils to choose from, do you feel stumped as to which one you should be buying and using based on your needs? Fear not! Here we will explain the types of fat you should be including in your diet, along with how to do it.
WHAT IS THE FUNCTION OF OILS?
Fats and oils have many different functions in the body, including chemical, physical and nutritional. In food, fats and oils provide appearance and texture, flavour, nutritional value (provide calories and are needed for the absorption of vitamins A, D, E and K), satiety, solubility and heat transfer1.
FATTY ACID PROFILE OF OILS
According to various nutrition guidelines, 20 – 35% of our total energy should be coming from fat2. There are different types of fat that should be making up your total fat intake for the day. Of your total energy this should come from2:
- 15 – 20% monounsaturated fat (MUFA)
- 5 – 10% polyunsaturated fat (PUFA)
- <10% saturated fat
|Figure 1: Fatty acid composition of oils5.
Figure 1 depicts the fatty acid composition of various oils. As you can see, coconut oil is mostly made up of saturated fat, so you should limit the use of this oil. On the other hand, olive oil is mostly made up of MUFAs, which may help decrease your risk of heart disease. You should thus try to include this in your diet where possible.
COOKING TEMPERATURES & SMOKE POINTS
Cooking temperatures can vary depending on the cooking method1:
- Pan-frying / sautéing on stove top: 120°C
- Deep frying: 160 – 180°C
- Oven baking: below 200°C
When you expose cooking oils to high temperatures, oxidation and a number of other chemical changes start to occur. If oils are heated too high, or for too long, they can start to breakdown and form a number of by-products1. The type and quality of oil, as well as the temperature it is exposed to are some of the factors that dictate the chemical reactions that take place. The end result of heating oil too much and for too long is decreased nutritional value of the oil and the by-products may have adverse health effects1.
The temperature at which an oil starts to break down is known as its smoke point. Different oils as well as whether they are virgin, semi-refined, or refined, have different smoke points as seen the table below3.
|SMOKE POINT (°C)
|Refined canola oil
|Unrefined sesame oil
|Refined avocado oil
|Refined soy oil
|Virgin olive oil
|Extra virgin olive oil
|Refined coconut oil
|Unrefined coconut oil
|Extra virgin olive oil
|Unrefined peanut oil
|Unrefined soy oil
|Unrefined canola oil
|Unrefined flaxseed oil
|Unrefined sunflower oil
You may have been told to cook with olive oil as it is the healthiest for you, but just be aware of the type of olive oil you are using, as well as the temperature you are going to expose it to. For example, if you are going to be pan-frying a food, it may be better to use virgin olive oil as opposed to extra virgin olive oil.
OILS TO CHOOSE BASED ON ITS USE
Based on the smoke point, some oils would be suitable for cooking at high temperatures. However, some oils may have a high smoke point, but also have a very strong flavour. Can you imagine the taste of French fries cooked in avocado oil? Beyond the taste, avocado oil is expensive.
To make things a bit easier for you, the below table lists the oils suitable for various cooking methods or uses4.
|COOKING METHOD / USE
Coconut oil (moderate amounts of virgin coconut oil in curries, etc.)
Peanut oil (if this is the flavour you are looking for. . .)
|Coating pots / pans / grill
Store oil away from light and heat. A cool, dark cupboard may be just the place. Some oils, especially those high in PUFAs (e.g. grapeseed oil) are prone to turning rancid quickly. Rather store these oils in the fridge.
Understanding the chemistry behind the oil is key to knowing which oil you should be using and for what. The less exposure to heat the better, where some oils are more tolerant than others. After going through this article, I am sure you will be able to impress your guests at your next ‘come-dine-with-me’-styled dinner party!
- Cooking with Extra Virgin Olive. Gray, Sarah. 2, s.l. : ACNEM Journal, 2015, Vol. 34.
- Position of the Academy of Nutrition and Dietetics: Dietary Fatty Acids for Healthy Adults. Dietetics, Academy of Nutrition and. 1, s.l. : Journal of the Academy of Nutrition and Dietetics, Vol. 114.
- [Online] http://www.cookingforengineers.com/article/50/Smoke-Points-of-Various-Fats.
- [Online] http://www.eatright.org/resource/food/planning-and-prep/cooking-tips-and-trends/all-about-oils.
- [Online] https://blogs.extension.iastate.edu/spendsmart/2013/08/19/vegetable-oils-comparison-cost-and-nutrition/.