All about Cooking Oils-By Dr Harold

Script:

All cooking oils are not the same

Many years back there was not much of a choice of cooking oils. Lard obtained from pig fat was very popular. I remember in the 1950s in Singapore they used lard in street noodle outlets. Lard has about 40% of saturated fat:50% of monounsaturated fat and 10% of polyunsaturated fat. Smoking point is 218 deg. C. ideal for deep and stir frying. It is low in saturated fat unlike other animal fats, butter, tallow, and high in heart friendly monounsaturated fat.

Today most oils used in street food outlets and hotels is vegetable oils. Lard wasdemonized though much better for health than the faked processed vegetable oils.Lard has a better flavour and texture when used as a cooking oil.Vegetable oils from corn and rape seed which produces canola oil, are cheaper and popular, used for most dishes today.

Fish and chips outlets use vegetable oils. Mind you, when you use any cooking oil as a rule must be discarded after the first usage, because of the free radical formation.The oil that is used in the fish and chips industry, seems to use the same oil repeatedly during the whole day, and from a health point of view, it is best to avoid.Free radicals generally seem to shorten your life.

Today, in the super-markets there is a load of cooking oils, includes extra-virgin oil,coconut oil, sesame oil, peanut oil, grapeseed oil, avocado oil, sunflower oil, and so
on.

For Asian curries and cuisines, coconut oil seems to be the most popular and hasstood the test of time.
Coconut oil is extensively used in cooking fish and vegetables in Asian curries and is very stable, does not go rancid. Coconut oil has a high smoke point andlonger shelf life than some other fats. As it is solid at room temperature, it can be used in baking recipes, for frying, for greasing baking pans and as a replacement for butter or vegetable oil in recipes.
Let’s go deeper into saturated and unsaturated fats.

You are aware that a molecule of water is composed of two hydrogen atoms linked to one oxygen atom.
So, on boiling water at 100 deg. C, you get pure healthy steam.On the other hand, fatty acids that form fats are composed of chains of carbonatoms linked together with a pair of hydrogen atoms hanging on, either side of each carbon atom. You may refer to this as a long hydrocarbon chain consisting of carbonand hydrogen atoms.

All oils have a variable smoking point unlike water that steams at 100cOils vary in their smoking points, and the unhealthy smoke comes from the carbon chains, unlike water when boiling emanates steam. 

Classification
Fats are classified as saturated fats and unsaturated fats. A third kind of artificial or synthetic fat is trans-fat.
In a saturated fat, all carbon atom chain is filled with hydrogen atoms linked on each
side of each carbon atom.
Let me describe this in a simpler way.
If you get into the train, and when you look around there are no vacant seats. Thenwe say the train is saturated.
In fatty acids the seats are carbon atoms and the occupant are a hydrogen atom.
When you talk about unsaturated fatsUnsaturated fats are liquid at room temperature.
They differ from saturated fats that their chemical structure contains one or more
double bonds

Unsaturated fat typically comes from plant sources such as olives, nuts or seeds.
Also present in fish.
Unsaturated fat could be monounsaturated or polyunsaturated.
With monounsaturated fat there is one pair of hydrogen atoms missing from a carbon atom and its double bonded
In polyunsaturated – there are many vacant carbon atoms with many double bonds

Nutrients lost in cooking

Cooking at high temperatures in oil and large quantities of water for longer times cause micronutrients in the food to get lost, such as water-soluble vitamins likevitamin C, Thiamine, riboflavin, vitamin B6 and B12, niacin and folate in green
veggies.
When little water is used for cooking green veggies, retain most of the minerals and vitamins.
Root veggies retain minerals and vitamins regardless of the amount of water used.
Let’s talk about trans fats or hydrogenated fats
The term “hydrogenated,” as in hydrogenated vegetable oil, means hydrogen is added to the oil. This process turns a liquid fat such as vegetable oil into a more shelf-stable, solid, and spreadable fat, such as margarine. Some oils are only partially hydrogenated, and in this process some monounsaturated fatty acids arev converted to saturated fatty acids (trans fats) that are harmful and can raise
cholesterol and increase the risk of heart disease.
It is best for health reasons to avoid eating frozen food in the supermarket, as you
know trans-fat is used to increase their shelf life and prevent going rancid.
They raise your bad cholesterol and lower your good cholesterol.
Eating trans fats increases your risk of developing heart disease and stroke. It’s also
associated with a higher risk of developing type 2 diabetes.
Remember what your grandmother told you.
Always cook your food in little water like curries and add a few tablespoons of
coconut milk for flavour or steam your veggies.
Restrict using oils for deep and stir frying as both results in high dense high calorie
flavoured foods that stimulates to eat more and result in inflammatory diseases like
coronary heart disease, stroke, obesity, diabetes and so on.
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