Which oil should we use for cooking our foods? Here’s my one line answer: get either cold pressed or expeller pressed oil that your regional Indian cuisine uses traditionally, whether it is sesame oil, coconut oil, mustard oil, ghee, etc. or a combination of these oils.
Well, I’m sure there are some readers thinking, “Oh, here comes a mommy blogger who wants us to stay away from refined oils.” Yes! this mommy-engineer-blogger wants you to stay away from refined oils and I explain below why in scientific terms. So, read on….
Why did we stop using cold pressed oils?
Let’s travel back in time briefly. The concept of refined oils began only around 1911 or so and caught on full steam to the Indian consumer only by the 1960 or 70’s. Ask your grandma what oil they used, and most likely they will tell you some story of how got their oils from a wooden chakki (mechanically expressed) oil retailer in the neighborhood. They will probably rave about the smells of the freshly made oil and they will extol its culinary capabilities as well.
They probably didn’t look up its smoke point…Or research its breakup of monounsaturated: polyunsaturated: saturated fats. They probably didn’t wait to be told by a marketing agency that it was ‘heart healthy’. Instead, they got their oils at their freshest, loaded with its natural antioxidants. And they replenished their supply when it was over within a few weeks.
You see, they got their oil source from the shortest supply chain possible!
It went from:
Seed/Fruit (farmer) -> Oil maker (who was also retailer)-> Consumer (grandma).
Now, we get our oils with a fairly long supply chain.
Seed/fruit farmer -> Oil production/refinery -> Storage/transport -> Grocery Chain Warehouse -> Grocery Chain -> Consumer (you)
This addition in steps + the delay of oil reaching consumer’s hands required it to be more shelf stable, long lasting. But, did the refining process actually help? Not necessarily, refining does not automatically mean more stable oils; but more on that later…
But, even if we did accept that refined = more stable; isn’t that backward thinking? We are refining oils to suit the needs of a grocery chain, not our nutritional or culinary needs.
History of Refined Oils
Just google Crisco! You will get amazing information about how Proctor & Gamble (a soap manufacturer) managed to sell cotton seed oil as this amazing ‘vegetable oil’ called Crisco (Crystallized Cotton Seed Oil). You see, back in the 19th century, cotton was being produced for clothing. The by-product of cotton processing, cotton seed was considered virtually worthless. Early attempts to mill those seeds resulted in oil that was unappealingly dark and smelly. Most farmers left the seeds to rot or illegally dumped them into rivers. There is literally no culture that had used cotton seed oil for cooking or food until then.
Along came a chemist named David Wesson who pioneered industrial bleaching and deodorizing techniques that made cottonseed oil become clear, tasteless and neutral-smelling.
Initially, cotton seed oil was restricted to only making soaps (Ivory Soap – famous for its white color) and candles. But then, they found a way to ‘hydrogenate’ the oil. What it means is that they were able to make a liquid oil into a semi-solid, creamy oil. And they were amazing marketing geniuses. They claimed, Crisco was made from “100% shortening,” “Crisco is Crisco, and nothing else.” They gestured towards the plant kingdom: Crisco was “strictly vegetable,” “purely vegetable” or “absolutely all vegetable.” They popularized the term “vegetable oil,” whatever that meant!
And this Crisco marketing strategy was, unfortunately, copy pasted pretty much in India!!
First cottonseed oil mill in India was established at Navsari in 1914 and apparently it took many efforts from Government and entrepreneurs to promote its use as edible oil and to convince cattle owners to use cottonseed cake in place of whole cottonseed for feed purposes. Today annual production of cottonseed oil is about 13-14 lakh tonnes and it is the third largest contributor to the Indian edible oil basket. It has become popular in cotton producing states mainly in Gujarat.
And those poor animals who are fed cotton seed cakes. There are pigment glands in cotton stems, leaves, seeds, and flower buds that produce a substance called Gossypol. Gossypol provides the cotton plant with resistance to pests, but in turn promotes several toxic effects when used in high concentrations in animal feed. Free gossypol may be responsible for acute clinical signs of gossypol poisoning in cattle which include respiratory distress, impaired body weight gain, anorexia, weakness, apathy, and death after several days. However, the most common toxic effects is the impairment of male and female reproduction.
Granted that cottonseed oil that is refined for cooking purposes limits gossypol to very low levels, but do we really need to do all this chemical gymnastics to be able to eat cottonseed products. Isn’t getting cotton fiber enough?
And thus I present to you the theme for refined oils. Take a cheap byproduct or a cheap seed oil that cannot be consumed in its raw form, refine it until you no longer recognize it and give a clear, ‘neutral-tasting’ liquid to the consumer to use.
It all comes down to mass manufacturing & money
Everything in the oil industry basically comes down to yields, byproducts and savings. Nutrition is barely in the picture. Let’s look at the 2 processes to create refined oil: 1) Solvent Extraction and 2) Refining Process. Let’s look at the 2 processes in detail.
The traditional techniques to extract oil was either cold press ( crush the seeds at low temperatures to release the oils) or expeller press (using a mechanical screw press). However, majority of the oils you get in the market today are extracted using solvents, the most popular of which is hexane.
Why do we even get into using hexane solvents in the first place? Let’s take the case of soybean oil. Mechanical pressing of a low-fat oilseed like soybean (<20%) yields only 50-70% of the available oil, in contrast to the solvent extraction method which recovers over 98% of the oil!! I mean, I hate to say it, but that’s impressive!!
So hexane is used to literally squeeze every last drop of oil out of the seed or bean. Next what? Hexane evaporates quickly and will boil at 154.4 degrees Fahrenheit, so almost all the hexane is recovered, any left over in the oils is captured in the de-odorizing process that takes place later.
But just look at the hexane trapped in the meal. Nearly 1/3 of the lost hexane is trapped in the meal.
This meal is toasted (to remove remaining hexane), dried and sold as animal feed or defatted soya chunks, defatted peanut flour, etc.
A study found 21 ppm of hexane in soy meal. The authors of the study also found concentrations as high as 50 ppm. While, no study has ever tested how much hexane a person can safely eat over the course of a lifetime; I for one would prefer my soya chunks without hexane, wouldn’t you?
Back to oils….
Refining until you reach “clear, neutral-tasting oil”
Refining is basically striping the extracted oil down to its bare minimum and giving you a clear liquid at the end. Are you ready for the steps needed in refining? Let’s go…
1) Degumming: is the process of removing the phospholipids from the oil along with any particles. But Phospholipids can act as natural antioxidants in the oil. It is a good thing, yes?
Why are we removing it then? – Since phospholipids has emulsifying properties, it will interfere with the next process of refining – alkali neutralization. So, unfortunately, phospholipids are stripped away!!
2. Neutralization: Here, the free fatty acids (FFAs) in the crude oil are stripped with sodium hydroxide (NaOH) in an aqueous solution. This is done to increase the smoke point. The smoke point of an oil increases as free fatty acid content decreases.
But, sometimes this is not needed!! In some cases like extra virgin olive oil, the free fatty acid levels are naturally low and match values of refined vegetable oils at or below 0.8% (0.8g per 100g) without undergoing such harsh processing.
And sometimes this is unnecessary!! Extra virgin coconut oil and unrefined sesame oil have a naturally high smoke point of 177c/350F. If that’s all I need for majority of my cooking and my tadka temperature (325 F) anyway, why bother going through this process?
I don’t need my oils to withstand the surface temperature of Venus, ya know….
3) Bleaching: As the name suggests, they use bleaching clays to absorb colors and some other contaminants.
But, again why??- Did you know that crude palm oil has an orange color to it and is considered the world’s richest natural plant source of carotenoids. Its retinol (provitamin A) equivalent content has been estimated at 15 times that of carrots and 300 times that of tomatoes.
What is the color of the palm (fruit) oil that you see normally in stores? – not orange! Thanks to the bleaching process!
4) Deodorizing: Just in case, there was any bit of nutrient (and yes grudgingly agree any contaminants as well) left, have no fear, deodorizing step is here. The oil is put under a vacuum and heated with steam (temperatures between 180° – 270°C) to remove any leftover taste or odors.
This makes sense for a terrible tasting oil like cottonseed or a terrible smelling oil like Canola. Not the wholesome ones!!
Think of the perfect candidates for refined oils. I think the whole refining process works perfectly fine for processing cheap byproduct oils like cottonseed oil. Or even for oils whose unrefined versions have smoke points that are super low at 107 C/225F – safflower, sunflower or canola . Or it is fine if you want to run a chips or French fry business where you are deep frying every single day.
But, do we really want to have refined oils to cook with on an everyday basis?
Is all that refining process worth it?
So, final question then becomes: was all the chemical refining process worth it? And the answer, according to me, is Not Always!!
There are several studies that show that Extra Virgin Olive Oil (EVOO’s) fatty acid profile and natural antioxidant content allows the oil to remain stable when heated. In contrast, refined oils like Canola oils generated high levels of by products. Of all the oils tested; extra virgin olive oil, (EVOO), virgin olive oil, olive oil, canola oil, rice bran oil, grapeseed oil, coconut oil, high oleic peanut oil, sunflower oil and avocado oil, EVOO was shown to be the oil that produced the lowest level of polar compounds after being heated closely followed by coconut oil.
Here’s another study that shows that vegetable oil, despite containing significantly higher amounts of vitamin E, was highly susceptible to oxidation under frying conditions when compared to all olive oils.
So, why am I only pointing mostly to studies of Extra Virgin Olive Oil and coconut oil. Because that’s what I could find for now. But, I am very certain, that it is only a matter of time before we start seeing papers published on cold pressed sesame oil, mustard oil and ghee. There are already plenty of papers pointing to the positive attributes of virgin sesame oil.
For eg, this study states that high oxidation stability of expeller pressed or virgin sesame oils could be attributed to presence of lignans (sesamol, sesamolin, and sesamin) and tocopherols. This paper explores sesame oil with particular focus on sesamol and its derivatives having nutritional and cardioprotective properties.
My conclusion is that you should buy cold pressed or expeller pressed, unrefined oils if you can afford it. But, make sure it is from a fresh source. Buying oil is the opposite of buying wine. You want them fresh and not rancid. Buy it in small quantities. Store them in a dark bottle and keep it in a cool place. Encourage small manufacturers who are trying to enter the cold pressed oil business.
Stay away from refined oils if possible. They are developed with purely market share and profit margins in mind, very little nutrition, if at all any. Remember, the world survived just fine until about a 100 years ago without refined oils. Mario Batali deep fries in extra virgin olive oil, and I’m sure your grandma will point you to a good non-refined oil to fry your bakshanam in as well. You will be fine!!
Are you curious to know why certain oils (like sesame, mustard, etc) ended up being the top choice for certain cultures and traditions? And what is the big deal about saturated fats? Why is Palm oil so popular? Find out in Part 2 of this series!!