Vitamins, enzymes, omega fatty acids...? These substances somewhat remain in oil and are somewhat removed during refining. But what substance is never observed in crystal-clear, refined and deodorized oil?
The right answer is that we won’t see any sediment!
So, fine whitish substances floating in oil and forming a barely visible “net” – suspension of fine particles – are called Phospholipids. These tiny particles can settle out into whitish sediment at the bottom of an oil bottle.
As an example, how could we visually observe phospholipids in oil?
Most olive oil is made by “extra virgin” process – virgin cold pressing, i.e. without refining and deodorizing, that allows keeping phospholipids. You've probably noticed that olive oil becomes white when exposed to the cold. Phospholipids in oil become visible with decreasing temperature. Conversely, they become almost colourless at increased oil temperatures. If we cool down a bottle of virgin cold-pressed sunflower oil, we'll observe the same effect – oil will become white as it contains phospholipids.
This is due to the fact that phospholipids are a part of cell membranes that show themselves as solids with decreasing temperature and transform into a liquid-crystal state with increasing one.
What are Phospholipids from consumers' viewpoint?
Phospholipids are the most healthy, tasty and flavoured oil component that adds flavour and pleasant scent to sunflower oil. Their absence, accordingly, makes oil completely tasteless and odourless. Therefore, in 99 cases of 100, one is not able to determine by taste whether refined and deodorized oil was made of pumpkin, sunflower or rape seeds.
An interesting question is: how do phospholipids affect human health?
Probing deeper into biochemistry, we can see that phospholipids are a part of all cell membranes. Plasma exchanges phospholipids with erythrocytes. This determines their main property – the ability to form cell membranes (lipid bilayer).
Liver contains the largest number of phospholipids in cell membranes. Its cell membranes consist of 65% of phospholipids. Brain and heart follow liver by the phospholipids percentage in cell membranes.
Phospholipids form the basis of nerve cell membranes and are the main component of the nerve trunk sheath structure. Nerve cell responses deteriorate in their deficiency and may recover only by adding sufficient amount of phospholipids to food.
Being more hydrophilic than cholesterol (i.e. featuring more intense interaction with water), phospholipids act as cholesterol “solvent”. The cholesterol/phospholipid ratio in blood plasma predetermines the degree of cholesterol solubility in human blood vessels, while the cholesterol/phospholipid ratio in bile predetermines susceptibility to gallstone formation.
By the way, here is a simple test. If the same sunflower oil is tasty for your friend and tastes bitter for you, you should pay attention to your liver and gall bladder and undergo appropriate medical diagnosis.
Phospholipids in oil when cooking:
It should also be noted that phospholipids presence does not allow using oil for frying at high temperatures, as it is the suspension of barely visible whitish particles – phospholipids – that starts sticking. In other words, it is not prohibited to fry using “extravirgin” – virgin cold-pressed – oil, but you'll need more oil and should refrain from keeping it at critically high temperatures for a long time. Professional chefs recommend frying with the mixture of 40% of unrefined oil and 60% of refined one. It can be said that unrefined oil is rather intended for making salads and cooking at low temperatures.
From manufacturers' viewpoint. Why is the majority of oils produced refined and deodorized, i.e. why should a whitish sediment – phospholipids – be absent in oil?
Phospholipids are a litmus test of seeds and oil quality. In case of large-scale mass production it is impossible to ensure consistent quality of all sunflower lots by such organoleptic characteristics as taste and smell and such physical characteristics as humidity, impurity content, acidity, etc. If oil produced of a single undergrade sunflower lot is mixed with the total flow, phospholipids start oxidizing the entire amount of oil produced, which significantly reduces the oil quality and its shelf life – it may become unfit much before its planned "sell before" date expires. Besides, tasting qualities of such oil might raise questions. Therefore it makes sense for a mass manufacturer to “sterilize” oil by making it refined and deodorized, but at that time it becomes completely tasteless and virtually useless for human health.
In this blog entry we tried to present alternative view on oil production and empower consumers with additional knowledge that will help them to intelligent and informed product choices, based on personal nutrition goals and objectives.
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