Slick Extra Virgin

This report was what many in the extra virgin olive industry were waiting for. Big name supermarket olive oil brands labelled as extra virgin olive oil, randomly selected from Californian supermarket shelves, analysed by an accredited laboratory outside the US, tasted by internationally recognized taste panels, and the results reported by scientists with decades of standing in the edible fat and food industries.

You can get the report here,

http://olivecenter.ucdavis.edu/news-events/news/files/olive oil final 071410 .pdf

I’ve taken the liberty of graphically representing the data given in the report based on ‘origin’. I’ve used quotations around the word origin because when it comes to EU oils, what is on the label really doesn’t tell you very much about where the oil came from. Terms like ‘imported from Italy’ just mean that the oil was shipped from an Italian port. It doesn’t necessarily mean that it was made from Italian olives, or made in Italy. I visited the websites of the brands represented in the report, and if they made a big song and dance about being associated with Italy then I’ve put them under “Italy”. You can’t have your cake and eat it too!

If the brand was ‘generic’ or the producer was non-committal when it came to its country of origin then I’ve categorised them as ‘Mediterranean’. The US oils that were sampled were all Californian so their “country” is labeled as CA. Hell, CA’s economy is so big then it may as well be one!

Here’s what the report means to buyers of extra virgin olive oils available in Californian supermarkets..

General Quality – Acidity Level

Acidity is a general indicator of how healthy the olives were at processing and how quickly and carefully the olives were processed into oil. The lower theacidity the better.

The report showed that the extra virgin olive oils coming out of California outshone the EU oils on this very important criteria. The green arrow on the graph above shows a typical acidity for a good quality well made EVOO. With riper oils you can add up to 0.1% to this as they typically have a slightly higher FFA, but anything over 0.35 is stretching the boundaries of high quality EVOO.

All but one of the oils sampled passed the acidity test for EVOO based on the limits set down by the International Olive Council and the USDA. This wasn’t surprising as the 0.8% cut-off for EVOO is so high that just about any oil can pass. I’ve written about this in other blog entries, so I won’t go on another rant here.

How oxidised were the oils?

One of the measures of oxidation given in the report was Peroxide Value (PV). This value is particularly useful in assessing the potential for a young oil to go rancid. So the lower the value the better. However PV doesn’t do a good job in describing the oxidative state of olider oils. The following measure that is discussed (K232) strongly suggests that many of the EU oils were actually quite old at the time of testing. So I think the peroxide doesn’t tell the entire story about oil oxidation. Despite this caveat, the CA supermarket oils generally displayed a lower potential to oxidise than did the  EU oils.

The Check for Old Oil – this one always gets them when it’s done!

Finally the dead give-away! A high value for the measure known as K232 is generally regarded as a good indicator that the oil contains old oil (i.e. oil from previous seasons), so clearly the lower the value of K232 the better. In the world of supermarket oils, back blending using old oil is a pretty common practice. Older oil are cheaper to buy on the bulk market and/or producers have to sell the oil that they made but couldn’t sell in a single season. Now while some brands may not be back blending, others might blend in a small proportion (less than10%) of unsold oil from the previous season, while others might be blending in 50% of three or four year old oil. The K232 measure tells us quite a lot about what is happening in the back blending rooms.

This is where many of the EU oils are caught out. Even by their own standards, a good proportion of EU oils failed this test. All the CA oils were well under the limit suggesting they were much fresher. Incidentally, EU oils tested by independent testing agencies in other countries have also found this (but haven’t published the results).

So what’s the big deal about blending back old oil? Here’s the rub:

• By definition old oil has used up quite a bit of its shelf life outside of your kitchen.
• Generally old oil has a higher acidity and therefore it will smoke at a much lower temperature, making it less useable.
• Old oil has lower health giving polyphenols as they naturally oxidise over time.

But most importantly

• Old oil doesn’t have that fresh lively vibrant wonderful olive flavour which we pay a premium for.

As a footnote, you’ll note that I’ve always referred to the oils in the report as ‘EU oils’, rather than ‘imported oils’. The reason is, that there are many extra virgin olive oils being imported into the US from outside the EU – Australia, Chile and Argentina to name a few. Some of these nations are becoming significant exporters and in general have higher expectations as to what constitutes a quality EVOO.

RG

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Most producers of extra virgin olive oil provide nutritional and other information on their labels. Here’s my attempt at deciphering what it all means.

I’ve used a label off an Australian supermarket extra virgin olive oil as an example. Australian oil labels tend to provide lots of detail as to what is in the bottle, so most of the stuff you find on them, you’ll also find on labels elsewhere.

The first figure shows the nutrition panel while the second gives the label in its entirety. Below are the explanatory notes relating to the number codes given on the figures.

1.    Energy values: Better known to most of us as calories. All olive oils including extra virgin and the refined ‘pure’, ‘light’ and ‘olive oil’ have pretty well the same energy (calorific) values. The marketing term ‘light’ refers to the oils colour and taste, NOT its calorific value.

2.    Olive oil does not contain any protein, carbohydrates, sugar or salt (Sodium). This is not surprising really as none of these things are soluble in oil. These things are mentioned on labels either to inform the consumer (fair enough)or because it is a legal labeling requirement (or both). EVOO’s do contain trace amounts of cholesterol but as the levels are so low, they are rarely mentioned on labels.

3.    Total Fat: All olive oils comprise essentially 99.9% fat. 100mls of olive oil weighs about 91.5 grams. But remember that there are good fats and there are bad fats.

4.    Saturated Fat: The lower the better.  All edible fats including olive oil contain some saturated fat. Olive oil has a comparatively low amount ranging from 7.3 to 33.3 gms/100mls with an average value of around 14 gms/100mls (2.1gms/15ml serving).

5.     Monounsaturated Fat: The higher the better. Olive oil is a very rich source of these heart healthy fats. The mono fat content in EVOO ranges from 50.6 to 79.8 gms/100mls with an average value of around 67 gms/100ml (10gms/15ml serving).

6.     Polyunsaturated Fat: The lower the better. Olive oils contain low levels of these fats relative to many other edible oils. While they are pretty healthy fats, they are oxidise easily which means that their presence aids in reducing the shelf life of the oil. So on balance, the lower the polyunsaturated fats the better. Olive oils contain between 3.2 to 20.1 gms/100mls with an average of around 10 gms/100ml (1.5gms/15ml serving).

7.     Trans fats: Extra virgin olive oil naturally contain miniscule (and I stress miniscule) levels of trans fats. But to keep things in perspective, even at the levels reported on labels you would have to eat over 140 litres of EVOO (175 years worth of olive oil for the average American) to get the same amount of trans fat as eating a single serve of fast food French fries. Most oils contain far less than what even the labels say . Labels are pre-printed in their thousands, so producers often err on the conservative side i.e. overestimate things like this. But in many countries producers are allowed to claim zero trans fat if their oil falls below a 0.0buggerall% threshold.

8.   ‘Best by’ date: This is probably the most confusing and in some cases, meaningless of all labeling requirements as it depends on where the oil comes from and where it is being sold. But here goes.

European Union: The stated ‘best by’ date is 2 years after the date the oil was packed/bottled.  This means little as oils are often held in tank for years before they are blended and bottled. So the oil could be well on their way to rancidity even before it hits the supermarket shelf. So the ‘best by’ date is pretty meaningless. It really should change, but it won’t.

Other countries: From what I’ve seen, most of the larger producers outside the EU mostly follow the EU approach. When in Rome, do as the Romans do I suppose.

Australia: Producers that have signed up to the Australian industry code of conduct base their ‘best by’ date on an objective measure of the predicted longevity of the oil called the rancimat test.

An alternative approach to stating ‘best by’ dates is to simply state the year, or year and month that the oil was extracted on the label. This approach is mostly taken by smaller producers. Even if this detailed information is provided, it is still impossible to predict how well the oil inside the bottle will last as the natural variability in the chemistry of EVOO’s determines their shelf life. However, most oils will last the 12 months required before the following seasons oils are released provided they are stored in a cool dark place.

9.     Product of Whatever Country:  Something so simple should be simple, but it isn’t

European Union: From July 2009 (and not about time I must add!!), olive oil originating from just one country will have to be labelled with the country of origin. Blends will be labelled either as “blend of European Community olive oils”, “blend of non-EU olive oils” or “blend of EU and non-EU olive oils”. Up until that date, the country of origin could have simply been where the oil was blended or packed, which allowed zillions of litres of Spanish or North African oil to be labelled as Product of Italy. I must say that even one year after the new law came into effect I haven’t seen a single EU oil on my antipodean local supermarket shelf labelled in accordance with this new law. Old stock perhaps?

Australia (and New Zealand): Oil labeled “Product (or produce) of Australia” must have been made from Australian olives and it must have been produced in an Australian mill. The same applies to oils labeled as Product of New Zealand.

The US: Who knows? I’ve seen Californian maps and references to California splashed all over the front label, but printed in 2pt font on the back is the enlightening “Product of the Mediterranean”. Stuff like this must drive the hard working legitimate local producers insane!! The new USDA olive oil standards do not as popularly assumed address labeling issues – even basic ones like knowing where the oil you are buying actually comes from. So read those back labels carefully. I follow the general rule, that if the statement of origin is even slightly ambiguous I move on to something else.

11.     Contact name and address of the producer: Maybe this appears to be a small thing, but it actually means a lot. It allows a real human being to take responsibility for what is in the bottle you just bought. Too often dodgey EVOO’s have not been able to be traced back to the actual person who is profiting from the fraud. Incidentally under Australian law it is mandatory for all food producers to put the name of a legal entity and a physical address on the label.

Other things you might encounter on an EVOO label sooner or later:

Free fatty acidity or acidity or FFA. The lower the better. Look for EVOO’s with FFA’s less than 0.25%. I’ve raved on incessantly about this in some of my other posts.

Polyphenol level: It is rare to see this stated on a label as they deciline over time. But some producers do give the level at bottling. Polyphenols are antioxidants. They are a healthy part of our diet and help the oil survive its year long journey in your kitchen. However it is worth noting that generally speaking, the higher the polyphenol level the more bitter and peppery the oil.  A polyphenols value of 500 mg/kg +indicates a pretty intense oil and less than 150 a pretty gentle sweet oil. You can read more about what effect polyphenols have on the taste of EVOO in Gawel and Rogers (2008), the authors version can be found here; http://www.aromadictionary.com/articles/oliveoilpolyphenolsandstyle.pdf

Lots of harmless bullshit: But heh, the world wouldn’t be as much fun without it, and it doesn’t hurt anyone most of the time.

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EVOO oxidises in two ways. One is called auto-oxidation and the other, and arguably the most destructive sort, is known as photo-oxidation. Photo-oxidation as its name suggests in initiated by light.

The good old fashioned oxygen that you find in air and that is dissolved in EVOO isn’t by itself very destructive. However, if it is hit by light which is packed with enough of an energetic punch, then it can push the generally harmless oxygen to a new and dangerous psychotic state. This energised oxygen, called triplet oxygen starts a destructive chain reaction, oxidising fat molecules left right and centre. The ultimate result of this reaction is a rancid oil that lacks fresh olive flavours, and worst still, fills your food with aweful flavours of old fish and chip shop or suburban corner grill.

Photo-oxidation can be simply avoided by ensuring that the oil is not exposed to light. To this end, good EVOO producers pack their oils in dark glass bottles or cans, and they implore their customers to store their oils in a dark place. While tin cans are completely impervious to light, dark glass is not. Different coloured glass of different levels of darkness are used to store EVOO. Look carefully: some are a classic green, others more of a “sea green” colour. Others are more olive in colour and yet others are amber.

Many producers think that the darker the glass the better, and that is all there is to it. Well they would be wrong.

Oxygen can only be energized if it is hit by light with a short enough wavelength – particularly light in the ultraviolet part of the spectrum. So, coloured glass that absorbs UV light will best protect the oil from oxidation. Those that let UV light through will not afford any protection to the oil, regardless of how dark or light the bottle appears to the eye.

So how do we measure the effectiveness of different glasses and material in blocking UV light? Scientists use a machine called a spectrophotometer or spectro for this gig. It sends a beam of continuously changing wavelength light through the glass and measures the amount of that light that doesn’t make it through (called the absorbance).

Each type of coloured bottle has a distinct ‘absorbance’ fingerprint. Some colours absorb light better at different wavelengths than others. Indeed, that is the exact reason why they are perceived by our eye as having different colours in the first place. The figure below shows the absorbance fingerprints of a variety of commonly used wine bottle colours (from Skouroumounis et al. 2006).

You’ll notice that there are a number of different types of green represented – classic green, antique green,  emerald green and the like. They’re all green but they clearly absorb different wavelength light to different extents. The glass labeled ‘flint’ is better known to us as clear glass. It doesn’t absorb light at any wavelength. All the light just passes right through. Hence it looks clear and colourless.

But not all wavelengths are born equal when it comes to destroying EVOO. The ‘light’ with wavelength of 400 nanometers (nm) or less is known as ultraviolet radiation. Our eyes can’t see it but the spectro can. Below 315nm it is known as UV-B, and above 315 UV-A. (the dark lines on both figures represent these parts of the spectrum) .Both types have enough energy to excite oxygen and cause eventually cause rancidity. The absorbance at the other longer (visible) wavelengths gives the bottles their distinct colour.

So think about what the consequences would be of storing olive oil in cobalt blue bottles. They’ll look pretty funky (I guess), but cobalt blue glass doesn’t absorb very well in the UV part of the spectrum. So that means that any UV that hits the bottle will pass straight through the glass and attack the oil. And the glass will provide little protection regardless of how dark the blue. Darker blue glass will absorb more in the parts of the spectrum that don’t influence oxidation but will still let pretty well all the damaging UV light through.

So what about olive oil bottles? This morning I intentionally smashed two common types of square bottles that are used to store EVOO. I bought the oils at a local specialty store. One bottle was common dark green and the other an equally common dark olive green/brown colour. I also cut a bit out of a clear PET bottle used to store olive oil that I purchased at a supermarket and measured the absorbance from the visible through to the UV part of the spectrum. Here’s what the glass looked like and below that are the results.

(Yellow=PET, Aqua=green glass, Brown=olive green/brown)

Clearly the olive/brown version is better than green when it comes to blocking UV. But neither is perfect. So store those oils in a dark place regardless of the fact that they are in dark glass. The PET was a bit of surprise. It absorbed very well in the UV-B, but was pretty well a clear window for UV-A. Some PET contains inbuilt UV blockers. This was clearly one of them. Not that you could tell by looking at it!



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Given the size of the international olive oil industry it surprises me that so few studies have delved into what the average consumer actually knows about extra virgin olive oil. Things like – when you can use it – is it good for you – why it is good for you –and what is the difference between the different types of olive oil (to name a few).

The Rural Research and Development Corporation (RIRDC) provides very welcomed funding for extra virgin olive oil research in Australia. They recently commissioned a market survey that explored what over 900 Australian consumers knew about extra virgin olive oil (EVOO) (Sheppard 2008). I can’t see any reason why the results of this survey wouldn’t apply to consumers in the US, Canada and other Western countries. Please feel free to comment if you think differently.

I scoured the finished report and have summarised what I thought were some of the more relevant findings to those who produce and market EVOO.

The health bits first….

The results are pretty clear. Some were not that surprising – that ‘olive oil’ was perceived to be the healthiest oil, and that using it may assist in reducing cholesterol and lowering blood pressure.

The fact that the majority of consumers were aware that ‘olive oil’ is a rich source of antioxidants is a great outcome for EVOO producers. However, nearly 70% of those surveyed did not appear to appreciate the difference between olive oil types that are found in the marketplace. You could reasonably conclude from these results that millions of olive oil consumers purchase refined olive oil (labeled as ‘olive oil’, ‘pure’ and ‘light’) and think that they confer the same health benefits as EVOO. Sending the message about the dietary positives of polyphenols is one thing, but it all seems wasted if the consumer doesn’t understand that EVOO is the only source of polyphenols amongst olive oil types (and indeed all edible oils).

Many producers state the year of production on their labels. This practice is commendable as it informs the consumers about the freshness of the product that they are buying. From these results it is clear that consumers appreciate that fresh oils are healthier for you. My guess is that this comes from the general understanding that all fresh produce loses healthfulness over time. Extra virgin olive oil shouldn’t be any different – and it isn’t.

However over 6 out of 10 respondents didn’t feel that current season EVOO is necessarily better than last season’s EVOO. Perhaps the wording “should” suggests some form of compulsion, but as over half responded that they didn’t know whether olive oils should be used within 12 months of purchase suggests a general lack of understanding as to exactly how long one should keep an oil before it loses it vitality (or at least parts of it).

This one is no surprise. Salad dressing and drizzling are the only two categories of culinary use which EVOO is thought to be the most appropriate.

In all the other categories including the more obscure ones of roasting and soups/casseroles – ‘olive oil’ is considered to be the most appropriate choice. My guess here is that no one has a f’in clue as to how one grade differs from the other, so the generic (in the eyes of the consumer) ‘olive oil’ was selected as a defacto. I’ve assumed this because ‘olive oil’ and ‘light olive oil’ are essentially identical and have never been differentiated in the marketplace, but one was considered to be more appropriate for than the other for most culinary uses.

Olive oil of all types were not considered to be great candidates for deep frying. Strange really, as the refined olive oil grades of ‘olive oil’ and ‘light olive oil’ have smoke points similar to most other refined oils (such as canola, sunflower etc), and that good quality low acidity EVOO isn’t that far behind either. But years of uninformed press that has (until recently) gone unchallenged about the smoke point of EVOO has left many consumers thinking that olive oil in general is a poor choice when deep frying food.

This question was a classic. To gauge the general understanding of EVOO, the question was posed whether the colour of the bottle affects the quality of the oil.

Around 8/10 of the consumers surveyed either did not know or refuted the belief that storing extra virgin olive oil in dark glass bottles was any different than storing in clear glass bottles. Mmm…. Let’s start working on educating consumers about varietal differences then.

I’d like everyone that strolls up that shop aisle to understand that ‘olive oil’ is not the same as extra virgin olive oil either in taste or healthfulness, that light and heat are the enemies of olive oil, that you can use EVOO for things other than dressing or salads, that within EVOO there are different styles which are best suited for some applications rather than others, and that EVOO’s don’t get better with age.

I’ll leave the difference between Picual and Frantoio for another lifetime.

Source: Sheppard S. (2008) Consumer attitudes to Australian extra virgin olive oil. Rural Industry Research and Development Corporation Publication No 08/166. Canberra, Australia.

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Lots of people ask questions about extra virgin olive oil, but few have the time or energy to listen to complex, lengthy answers to their questions. Here’s my attempt at giving answers to some of the most commonly asked questions about extra virgin olive oil- all in 30 words or less.

What is Extra Virgin Olive Oil? It is the oil extracted from fresh good quality olives using a mechanical process without the use of excessive heat or any form of additives or solvents.

Extra Virgin Grade Olive Oil – what is it? If the olives are disease free and are processed without delay using a clean mill, they will produce a clean, fresh extra virgin olive oil.

Difference between extra virgin & pure or light olive oil? EVOO is the naturally extracted juice from fresh olives. Pure or light olive oils have been refined which removes all the flavours and natural antioxidants.

What is pomace oil? It is the lowest commercial grade of olive oil. It is solvent extracted from the waste material from olive oil production.

Do “light” olive oils contain fewer calories than EVOO? No. All olive oils (and indeed all edible oils) have very similar energy values.

What does “light” olive oil mean? The word ‘light’ is used in the context of the olive oils having light (minimal) aroma, flavour and colour.

Should I buy first cold pressed oil? Most EVOO is now produced by spinning the lighter oil away from the other components of the olive such as water and olive matter using centrifugal force.

Are extra virgin olive oils good for my health? EVOO’s contain higher levels of monounsaturated fats and antioxidants than other oils. These attributes are sought after by the health conscious.

What is meant by robust and mild EVOO? Robust oils have strong bitterness and/or pepperyness. Mild oils are much lower in these characters.

Does the colour of olive oil indicate quality?  No. Good quality extra virgin olive oils range in colour from emerald green through to golden yellow.

What do I look for in a retailer of EVOO? Someone who can advise on the right style of EVOO for your intended use and only stock new season’s oils. Even better, buy from the person who made the oil.

There are so many EVOO’s to choose from – what do I look for? Purchase an olive oil that is useful for the culinary purposes you require and buy current season’s oils as these will be the freshest.

What is the difference between early and late harvest oils? Early harvest oils are made from greener olives, and are often more herbaceous, bitter and peppery flavours. Late harvest oils are milder and display riper fruit flavours.

Where do I store extra virgin olive oil? Olive oils should be stored in a cool dark place. For longer term storage where oils are used infrequently, refrigeration is a good option.

How long can I expect my EVOO to last? EVOO’s are best consumed young when their fresh flavours and healthful polyphenols are maximised.  They do not improve with age. So when the new season oils are released, buy them.

Can I use extra virgin olive oils for frying? Yes. The smoke point of good quality EVOO is within the temperature range typical of shallow frying.

Can I reuse olive oil? Yes, they can be reused a few times. However, heating causes losses in flavour, freshness and healthfulness. It also begins to smoke at a lower temperature each time it’s reheated.

Can I use olive oil in the microwave? Yes, recent research has shown that olive oils heated by microwaving retain their natural polyphenols to a much greater extent compared with traditional heating methods.

What are the positive attributes of EVOO?  Fruitiness, bitterness and pepperyness. All good oils must have some olive character. Bitterness and pepperyness are optional extras, but most consumers like some of these characters.

What do bad oils taste like? The most common problems are staleness, brined olive, mouldy, salami, parmesan cheese, vinegary and solvent like.

What is the most common olive oil defect? Rancidity which smells like old oil, stale peanuts or putty. This is the inevitable result of the ageing of all edible oils – EVOO included.

What do words like Frantoio, Picual and Arbequina mean on a label? These are referring to varieties of olives from which the oil is made. Varieties are subtlely different genetic versions of the same olive species.

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The last time I visited California I stopped by a Malibu supermarket. I was surprised to find a large number of coconut products prominently placed for sale. Coconut milk, cream and oil. But it was the way in which some were packaged that really got me thinking. Clearly Gen Y. But why would an oil that contains over 90% saturated fat be attractive to the health conscious gym junkie? A few weeks after returning to Australia, I received an email from Deborah Rogers of the Olive Press in Sonoma asking me if I knew anything about coconut oil. I think that all the hype surrounding VCO was getting to her as well. Well I have to admit that apart from knowing that coconut oil is a major and traditional source of energy for our South Pacific neighbors, I didn’t know that much about it, or indeed why it should be prominently placed in a Malibu deli.

I promised Deborah that I would look into it – in particular why, something that on face value looked as healthy as a double B full of gamma irradiated lard should be even remotely popular. But I felt it would best to share.

The Two Faces of Coconut Oil

Coconut oil comes in two types. Refined and unrefined  the former is marketed as ‘coconut oil’ while the latter virgin coconut oil or VCO.

VCO is obtained from the fresh kernel of the coconut by mechanical or natural means and without undergoing chemical refining. The oil is obtained by a method called wet processing whereby coconut milk is pressed from fresh coconut. A component of the milk is called coconut cream then separates under the action of gravity and the oil is extracted from the cream by breaking the emulsion. Typically the emulsion is destabilised by either heating, chilling and thawing, fermentation using Lactobacillus sp. or enzymatic processes. VCO are typified by being almost colourless with some having a roasted, cooked, smoky or nutty aroma, sweet taste and nutty flavour.

However by volume, most coconut oil is refined. Refined coconut oil is typically made from the dried ‘meat of the coconut (called copra). The copra is ground and steamed, and then pressed either using a wedge, screw or hydraulic press to obtain a crude coconut oil. The crude oil is then bleached and deodorised. As with refined olive oil, refined coconut oil has no discernable aroma or flavour.

Virgin Coconut Oil and Extra Virgin Olive Oil Compared – Antioxidants

Compared with extra virgin olive oil, VCO is relatively low in antioxidants. Tocopherol is only found in the thin brown layer that clings to the white coconut meat, called the testa. There isn’t much of it and it is removed before the oil is extracted, so only trace amounts of tocopherol is found in virgin coconut oil.

The total polyphenols level of virgin coconut oil is a meagre 20-25 mg/kg (Marina et al. 2008). Compare that with EVOO which has a basement level 4 times that, and peaking at over 50 times the level of VCO (Gawel and Rogers 2009). In addition, the polyphenols reported in VCO are your common garden variety type. protocatechuic, vanillic, caffeic, syringic, ferulic and p-coumaric acids. Ok they sound impressive, but there’s nothing there that your average glass of red or white wine wouldn’t give you times 10. I’m sure there are very small amounts of other polyphenols in VCO which haven’t been reported yet, but to date it really looks like a pretty plain sort of oil, at least polyphenols wise.

Virgin Coconut Oil and Extra Virgin Olive Oil Compared – Saturated fat content

All of the common edible fats contain some saturated fat. EVOO contains around 10% saturated fat (the major fat being the monounsaturated oleic acid), while coconut oil contains a massive 90%. The figure below gives the average fatty acid profile of both oils.

So what is the big deal? Why does an oil with enormous amounts of saturated fats and hardly any polyphenols or vitamin E like tocopherol get so much recent attention?

There are a number of different types of saturated fatty acids. Most of them are pretty big molecules, consisting of chains of carbon atoms typically 16 to 18 long. These are called long chain fatty acids and are known to contribute significantly to coronary heart disease. The major ones are palmitic acid (16 long) which dominates that fat profile of palm oil (and fast food joints), and stearic acid (18 long) which dominates animal fats.

On the other hand, VCO is dominated by smaller saturated fats called lauric and myristic acid. At 12 and 14 carbons long (respectively) they make up around 45-55% and 16-21% of its total fat content (respectively). What oleic acid is to EVOO, lauric and myristic acid is to VCO. Some people have conveniently classed lauric and myristic acids as medium chain fatty acids (MCFA), but to be realistic, as far as MCFA’s go they’re a bit on the chunky side. MCFA’s are officially defined as having chain lengths of 6-10, so lauric and myristic acid sit a bit in no mans land, a bit long chain, a bit short chain….

Short Chain Saturated Fatty Acids – Reported Health Benefits

The classic MCFA’s are absorbed into the human body via a different mechanism than the longer chain saturated fats. They don’t need to hitch rides onto proteins like the long chain mob before they can be absorbed. They are transported directly to the liver while their longer chain counterparts are absorbed through the lymphatic system. This short-cut means that they get to where they need to go – express.

MCFA’s became uber-famous when it was reported that you could eat them and you could lose weight doing so! Yes, eat fat and lose weight. The perfect solution to the obesity problem in the developed world – including, no doubt, Malibu! The reason for this rather counter-intuitive situation has a lot to do with the fact that MCFA’s are absorbed in very different ways than conventional long chain fats. But as often is the case, the devil is the detail. Medium chain fatty acids DO increase fasting cholesterol and triglyceride levels when consumed in moderate to high amounts – just t like their long chain counterparts.

In  their excellent but ‘not for the faint hearted’ technical review of MCFA’s Marten et al. (2010) stated that “the amount of MCFAs that can be tolerated within one meal is limited to 25–30 g. Ingestion of larger amounts of MCFAs causes adverse gastrointestinal symptoms, including nausea, vomiting, bloating, gastrointestinal discomfort, abdominal cramps, and osmotic diarrhoea.” OK, they were referring to the 6-10 chain length group of MCFA’s. Whether the dominant saturated 14C fatty acid in coconut oil has the same effect is unknown. Maybe, lauric acid doesn’t upset your tummy, but then again maybe it doesn’t confer the same health benefits either.

Smoke Point

At 175-180C, VCO has a  lower smoke point than good extra virgin olive oil. The lower smoke point of VCO results from the dominance of short chained fatty acids. When oils smoke, it’s not the intact fats that are doing the smoking. They’re relatively heat stable. It’s the free fatty acids which are found in all virgin oils that smoke first. As a general rule, free fatty acids with a shorter chain length start to smoke at a lower temperature. Refined coconut oil on the other hand has a higher smoke point which is comparable to that of other refined oils (as all the free fatty acids are removed by refining).

I’m going with the flow

Personally speaking I’d prefer a bit of traditional mono stuff that you find in EVOO. No subtle coconut flavour, or bugger all polyphenols. And no guess work on whether or how good it is for you. I’d prefer the gorgeous olive flavour that lifts food to new heights- and the simpler the food, the greater the lift. (But you can stick the zillion mg/kg polyphenol EVOO into a Suisse horse tablet for the stressed exec. It tastes better that way anyway).

Richard Gawel

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I give my top 10 myths surrounding Extra Virgin Olive Oil ……

Myth No. 1 – Extra virgin olive oil is made from the first cold pressing of olives.

Can be, but doesn’t have to be!

Extra virgin olive oil (EVOO) is officially defined as the oil extracted from fresh olives using a mechanical process without the use of excessive heat, additives or solvents.

“Mechanical” is the key word here. Most EVOO’s that are made in commercial relevant quantities are not made by pressing but by centrifugation whereby the lighter olive oil is spun away from the heavier components of the olive such as water and pulp. Still mechanical, still EVOO.

A centrifuge used to separate EVOO from olive water and olive flesh, stone and skin.

Myth No. 2 – Refined olive oil such as pure and light olive oil is made from the second pressings of the olive.

If you don’t press, then you can’t second press!

Refined olive oils usually start their lives as very poor quality olives which typically have fermented to some degree prior to being processed. The extraction process that is used to pull the oil out of these poor quality olives is the same as that which is used to produced good quality EVOO. But the end result is an oil that tastes so bad that it needs further radical processing to render it edible. The process is called refining and amongst other things it removes all the flavour from the oil –both the good the bad and the ugly. The final result is a bland product that is sold under the names ‘pure’, ‘light’ and ‘olive oil’.

Myth No. 3 – When making EVOO, the olives are crushed using heavy mill stones.

Very romantic but the days of granite crushing stones powered by donkeys is pretty well gone. Stone milling is very slow and the resulting olive paste is subject to oxidation. Today, most of the olives that are destined to become EVOO are crushed using motor driven means, the most common being the hammer mill. The hammer mill consists of an outer stainless steel screen and an inner rotating arm powered by a high speed electric motor. The olives are squished between the screen and the rotating arm resulting in a relatively oxygen free paste.

Donkey replacement – A hammer mill showing the perforated screen and rotating arm.

Myth No. 4 – Extra virgin olive oil that is made by pressing is better than those made using a centrifuge.

A few years ago some scientific research was published that suggested that this was the case. However, there are two types of centrifuge – the early model (early 1970’s) 3 phase and the late (mid 80’s) model 2 phase. This research compared pressing with oils from 3 phase centrifuges. For a 3 phase to work, water must be added to the olive paste prior to the oil being extracted. The addition of water causes some of the healthy polyphenols and flavour to be lost from the oil. However 2 phase centrifuges work without the need for adding water so EVOO’s made using these systems have the same or more healthful polyphenols and flavour as do oils made using a traditional press.

The big advantage of either centrifugal system over pressing is that it is much easier to keep a centrifuge clean. The mats used in pressing can be quite absorbent (there are a number of different types) and tend to hold oil which can inadvertently taint forthcoming batches of olives. Centrifuges can be more easily maintained to spotless standards. The bottom line is that in general EVOO’s made with centrifuges are more consistent than those that are made using your average press.

Also when you think about it, there is nothing inherently special about a press except that they have been used for a long time – but so has the wheel –and I don’t see too many Model T Fords on the road any more.

Myth No. 5 – Extra virgin olive oil made using a press is healthier for you than those made with a centrifuge.

Quite the contrary. The process of centrifugation is by nature, a rapid and enclosed process that protects the oil from oxygen during the separation process. This means that the naturally occurring antioxidants in the oil are conserved and end up in the bottle. If you expose the health giving antioxidants in olive oil to oxygen before they are bottled, then they by definition are used up. Better to have them in the bottle so they can help you stay healthy.

Myth No. 6 – Extra virgin olive oil that is clear has been filtered.

Well it might be but it probably hasn’t. If you leave a cloudy olive oil in a tank for even a relatively short time, the grungy bits will naturally settle to the bottom under gravity. Decant the clear oil off the grungy bit and whollah… clear oil ready for bottling. How gorgeously natural is that. Filtering oil is a tedious and messy business. Why bother mucking about with filters when you can let gravity do the work.

Myth No. 7 – You can’t refrigerate extra virgin olive oil

Refrigeration is a very effective way of prolonging the shelf life of EVOO. While some oils may partially solidify due to the oil containing naturally occurring levels of saturated fats and/or waxes, they will return to their normal state when they warm to room temperature. The aroma and flavour of the olive oil should not be affected in any way by refrigeration.

One small word of warning. There is some evidence that multiple thaws of oils can slightly shorten its shelf life. So if you use little bits and pieces very frequently then it is a better option to find the coolest dark place where the oil doesn’t solidify (say 10-12C) and leave it there.

Myth No. 8 – You can’t cook with extra virgin olive oil.

Good quality extra virgin olive oil smokes at a higher temperature than poor quality EVOO. In fact the smoke point of good quality EVOO is quite respectable and as such they can be used for shallow frying without any hassles at all. You can even get away with deeper frying with a little care (most foods will deep fry at temperatures below the smoke point of good EVOO), but realistically the economics of deep frying with good quality EVOO is pretty questionable given their premium price compared with other oils.

Myth No. 9 – Cloudy extra virgin olive oil is more healthy for you than clear EVOO.

There is absolutely no evidence for this. Most clear EVOO’s get that way by natural settling under gravity and not by further processing. So why wouldn’t they?

Myth No. 10 – The greener the oil the better it is for you.

For some, green just shouts freshness. But like many things EVOO, it’s not always what it seems.

For some varieties, green oil means that the olives were picked when they were pretty unripe and at a time when they were full of healthy polyphenols – hence the myth.

However, this pretty basic rule doesn’t always hold. Some varieties like Koroneiki and Verdale tend to make greenish oils regardless of their polyphenols level. Cool climates also tend to favour the production of the green pigment chlorophyll, so oils with the same colour but grown under different climatic conditions can have very different compositions.

Look at the oils labeled A-D below. These were sampled from a recent Australian EVOO competition. The oil on the far right, while being nearly an opaque emerald green had only a moderate amount of polyphenols (170mg/kg). It was a Verdale oil from the very cold marginal olive growing climate of Tasmania. The second from the left came in at a massive 620mg/kg of polyphenols. The colour definitely belied what was actually in the oil. Lots of golden coloured EVOO’s have very high polyphenols and are pristinely fresh. So in short don’t get too tied up with the colour of EVOO.

But then again if green is your favourite colour then go for it. I must admit that it always looks great on the plate….

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Extra virgin olive oils (and indeed all edible fats) are actually a complex mixture of different fats – saturated, monounsaturated and polyunsaturated. The major fat in olive oil are the monounsaturated type. Other seed and vegetable oils have a different combination of these fats, but with the exception of some carefully created ‘high oleic’ versions of sunflower and rapeseed oils, all contain a lower proportion of monounsaturated fats than does extra virgin olive oil.

From a consumer point of view, oils with higher levels of monounsaturated fats are preferred by the health conscious as they are thought to reduce the damaging LDL and increase the good HDL in the blood. Monounsaturated fats also turn solid at lower temperatures than do saturated fats, so oils with higher levels of monounsaturated fats are less likely to solidify if stored in the refrigerator. Most importantly, monounsaturated fats are more resistant to oxidation than the polyunsaturated fats (like those found in abundance in flaxseed, rice bran and sunflower oils). Olive oils contain a higher proportion of monounsaturated fats which helps them maintain their freshness substantially longer than the poly-mob (which incidentally need lots of artificial preservatives to give them shelf life).

For these reasons, the relative proportion of monounsaturated to the other fats (known as the fatty acid profile) is of great practical importance.

The diagram below shows a ‘typical’ fatty acid profile of Australian extra virgin olive oils. These proportions are the average of over 500 EVOO’s submitted for analysis to one of the major testing laboratories in Australia. Thanks to Dr Rod Mailer from the NSW Department of Agriculture Oil Testing Laboratory for letting me present this data. While these are Australian oils, they are pretty representative of anything you will find throughout the world.

The predominant fat in olive oil is the monounsaturated fatty acid, oleic acid (or C18:1 on the diagram).

While all olive oils are high in monounsaturated fats, some are higher than others. So what determines the low from the high. The major determinants of monounsaturated fat content in EVOO are the variety of olive which the oil is made from, and the climate in which the olive is grown.

Some varieties like Arbequina which is widely grown in California and Catalonia generally have a lower percentage of oleic acid compared with other varieties. Others like Picual which is widely grown in Andalucia and also Australia are high oleic varieties as do the varieties Koroneiki and Coratina. The fatty acid profiles of a large sample of Australian extra virgin olive oils is given below (Figure created from the data of Mailer and Ayrton 2008). An Argentinian study also confirms these differences between the varieties Arbequina, Picual and Barnea (Ceci and Carelli 2007)

Before I get a barrage of comments from my American friends, it’s worth noting that Arbequina has strengths in other areas. It makes delightfully fruity versatile oils with generally low levels of bitterness. Great for those delicately flavoured dishes that don’t need that big hit of bitterness or pepper.

To the climate. Extra virgin olive oils grown in cooler climates generally have higher levels of the monounsaturated oleic acid and lower levels of saturated and polyunsaturated fats than extra virgin olive oils grown in warmer climates. So here in Australia it is not usual for EVOO’s grown in the cold almost English like climates of Tasmania to have oleic acid levels around and above the International Olive Council upper limit of 85% (presumably quite a few New Zealand EVOO’s would be in the same boat). Isn’t it strange that wonderfully pristinely flavoured EVOO’s with massive levels of the healthy fat oleic acid and tons of antioxidants could be denigrated under international convention to the level of ‘fruit oil’ under International Olive Council regulations. Unless you’re adding industrial green pigment chlorophyll to high oleic sunflower and passing it off as EVOO, then you don’t need an upper limit for oleic acid. Mmmm… come to think of it it happened in Italy recently. But still, if they were just a bit smarter they could have added a few percent of normal sunflower oil and they could have come in under the 85% upper limit. So go figure why the IOC would have an upper limit on the fat that everyone buys olive oil for!

So how can you tell what the fatty acid profile of an EVOO is? This is tricky… The labeling laws in many countries specify that the fatty acid profile must be given. Try looking at the back label. You may find the alleged amount of mono, poly and saturated fat in the product. However, the fine print often says that the values given are just an ‘average’. The fatty acid profiles of large supermarket brands vary from batch to batch as they are nearly always blends of oils from different regions and even countries (even if it does say ‘Product of Italy’!). So as the blend changes so does its fatty acid profile. Smaller producers often get their oils analysed by a laboratory just once, and use the result from year to year. The fatty acid profile from oils made from the same place doesn’t change much from year to year, but if the producer blends in oils from a new variety that they have that is coming on stream then its fat profile will almost certainly change. I can’t see the average small producer discarding thousands of labels because of a small change in the profile particularly given that the stated profiles of the larger supermarket brands are just rough estimates of what is actually in the bottle. Finally, many small producers just take the ‘recommended percentages’ off their trade association’s website. So in short, the back label probably isn’t a reliable source of information about the oil’s fatty acid profile. Asking the producer directly is probably the best option.

By the way, all the fatty acids in olive oil are odourless and tasteless, so the fatty acid profile doesn’t tell you anything about what the oil smells or tastes like.

Sources:

Mailer, R.J. and Ayrton, J. (2008) A survey of Australian olive cultivars to determine compliance with international standards. RIRDC Publication No. 08/167.

Ceci L.N. and Carelli, A.A. (2007) Characterization of Monovarietal Argentinian Olive Oils from New Productive Zones J. Am. Oil Chem. Soc. 84:1125–1136.

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Yes you can!     And yes you should….

One of my twitter followers/friends recently asked if extra virgin olive oil can be safely stored in the fridge. They heard somewhere that “the shelf life is reduced, and valuable polyphenols are lost during refrigeration”.

While I have heard this before I couldn’t recall seeing anything solid. However, on face value this seemed rather strange as we generally refrigerate foods so as to slow down oxidation rather than to speed it up.

After a thorough search I found that somewhat surprisingly, that only two scientific papers have reported the effect of refrigerating extra virgin olive oils. One was probably the one that my twitter friend was referring to.  I read both the abstract (the summary which is freely available) and the whole paper (which is not). I’m not surprised that the abstract led many to believe that refrigeration was detrimental to maintaining EVOO quality. However on close inspection the actual results clearly suggested otherwise.

In this work, a single EVOO was stored in the fridge at below its melting point 3C, and at 25, 40 and 60C (Calligaris et al. 2006). The oxidative state of the oils were monitored over a 7 month period using a well known measure called peroxide value.  They found that this EVOO when stored at 3C had almost exactly the same peroxide value over the entire 7 month period as when it was stored at room temperature (25C). Now as scientists this must have seemed a bit unusual as one would expect that the oil stored at the cooler temperature would have a lower peroxide value. Based on this they surmised that: “below the melting point , the oxidation rate was found to be higher than expected”.

‘Higher than expected’ yes, but the oxidation rate of refrigerated oil was still about the same or lower than when stored at room temperature. Unfortunately, this practically important last little bit didn’t make it into the summary. Here are the results read from their paper (Figure 4). You can see for yourself.

So despite what appeared to be reported in the summary, storing oils in the fridge was the best option of all those studied.

Ok some would be thinking… so it appears that storing the oil at room temperature is just as good as stroring in the fridge so I’ll just leave it in my pantry. Well maybe, but then again maybe not. The polyphenol level of the oil used in the study was a massive 772 mg/kg. This is around 3 times the average polyphenol level of your typical EVOO (Gawel and Rogers 2009).  Polyphenols are antioxidants, so in this particular case, the polyphenols are providing a massive amount of protection against oxidation. That particular oil probably could have withstood a nuclear test blast in the Nevada desert in 1952 and still be edible today. Whether an EVOO with a more typical polyphenol level of around 200-250mg/kg would have stood up that well at room temperature is debatable. That’s the risk of doing research using a single oil-particularly an odd one!

The abstract also reported “a decrease in polyphenols in the liquid phase” upon refrigeration. Anyone that read this would naturally think that the polyphenols disappeared as a result of refrigeration. It was an unfortunate use of terminology. What the authors were referring, was not the oil in its entirety after being thawed, but only the little bit that was still liquid at 3C. The polyphenol level of the entire oil after thawing wasn’t reported, but my guess is that it would be pretty similar to or higher than the oil stored at 25C (oils with lower peroxide values tend to keep their polyphenols longer). Ok that low phenolic liquid bit would be more prone to oxidation while sitting in your fridge, but the fact that it only made up around 20% of the volume and is being held at 3C has to be taken into consideration.

The second study on cold storage of EVOO’s showed similar benefits (Prenzler et al. 2007). Here a relatively low polyphenol EVOO was stored in 100ml bottles at room temperature, and the same oil in the fridge at 1^oC. After twelve months, the polyhenol reading of the room temperature oil was 148 mg/kg. The same oil stored in the fridge had a polyphenol level of 185 mg/kg.  Yes that’s right, refrigeration helped retain polyphenols, not destroy them. In addition the free fatty acidity, and all measures of oil oxidation (peroxide value, K232 and K270) were lower for the oil stored in the fridge.  Sure the authors did correctly report that the oil did age somewhat when stored in the fridge i.e. when compared to the oil when new. You wouldn’t expect any different unless the researchers used a cryogenic device like that in the Jupiter II in ‘Lost in Space’. But the important point is that the fridge stored oil did better than the room temperature stored oil on all counts of quality.

There are two relatively small issues in storing oils in the fridge. Firstly, once opened and resealed, the bottle has the potential to trap humidified air which may condense on the inside of the bottle which in turn has the potential to cause the oil to tire. This is probably only an issue if you constantly take the oil out of the fridge over a long period of time, and then again I think that the benefits of slower oxidation outweigh the potential costs. Secondly, very occasionally some oils refuse to thaw completely when taken out of the fridge. This is because some of the natural waxes found in EVOO just refuse to go back into solution. Don’t be concerned. The few chunky bits are harmless and will definitely disappear if you heat up the oil when cooking. I’ve only seen two cases of this in thousands of bottles so I wouldn’t loose any sleep over it.

For good measure here are the papers I’ve mentioned and yes, the blatant yet obligatory self citation.

Calligaris, S., Sovrano, S., Manzocco, L. and Nicoli, M.C. (2006) Influence of crystallization on the oxidative stability of extra virgin olive oil. Journal of Agricultural and Food Chemistry, 54, 529-535.

Gawel, R. and Rogers, D.A.G. (2009) The relationship between the total phenol concentration of virgin olive oil and their style as determined by their producers. Grasas y Aceites, 60, 134-138.

http://grasasyaceites.revistas.csic.es/index.php/grasasyaceites/article/view/560/574

Prenzler, P., Robards, K. and Bedgood, D. (2007) Quality enhancements of Australian extra virgin olive oils. Rural Research and Development Corporation Report.

https://rirdc.infoservices.com.au/downloads/06-135.pdf

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In my previous post I mentioned some of the recent research outcomes concerning the healthful phenolic called oleocanthal which is only found in extra virgin olive oil. Here are my summaries of the research, together with links to the authors summaries (abstracts).  I read all the papers and try to pick up on what I think is relevant to the producers and the users of extra virgin olive oil.  Hopefully I’ve done them justice.

The compound mainly responsible for pepperyness was identified as deacetoxy-ligstroside aglycon (now called oleocanthal). Andrewes et al. (2003) http://www.ncbi.nlm.nih.gov/pubmed/12590491?dopt=Abstract

The pungency producing and anti-inflammatory phenolic Oleocanthal was resistant to degradation during prolonged heating falling by less than 16%. However, its biological activity fell by around a third when heated under the same conditions. Cicerale et al. (2009) http://www.ncbi.nlm.nih.gov/pubmed/19166297

Median a-tocopherol levels of 263 Italian EVO’s reported as 151 mg/kg and the pungent oleocanthal as 85 mg/kg (94mg/litre). Servilli et al. (2009) http://www.ncbi.nlm.nih.gov/pubmed/19234678

Oleocanthal induced pungency was mostly perceived at the back of the throat and was most intense at 15 seconds. Significant variation between individuals was observed. Cicerale et al. (2009) http://chemse.oxfordjournals.org/cgi/content/abstract/bjp006

Compared with oleuropein and hydroxytyrosol the ‘peppery’ phenolic oleocanthal best protected red blood cells from oxidative stress. Paiva-Martins et al. (2010) http://pubs.acs.org/doi/abs/10.1021/jf9031052

Low doses of the major extra virgin olive oil polyphenol oleocanthal modifies amyloid-β_1-42 peptide the neurotoxin implicated in Alzheimers Disease. Leads to less synaptic and neuronal deterioration. Pitt et al. (2009) http://cat.inist.fr/?aModele=afficheN&cpsidt=22114732

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