Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Enthalpy on March 23, 2015, 07:07:47 PM
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Hello dear friends!
Just a bizarre thought... Palm oil is reportedly the cheapest one but is quite unhealthy, with a proportion of saturated fatty acids worse than even pork fat.
Would it be possible to remove 1 to 3 hydrogen molecules from each of its fatty acids? To my rudimentary (mis-) understanding, this is done with catalyst and conditions similar to the hydrogenation of unsaturated oils, which the food industry afforded the big way before palm oil got available.
Making palm oil healthier (but still affordable!) would be a nice goal, since people in poor countries now use the unhealthy palm oil as the basic cooking fat due to its price. If cheap enough, it can also run Diesel engines like rapeseed oil does; presently, palm oil's triglycerides are converted in fatty methanol esters to make biodiesel. It would also be a source of hydrogen as a sideproduct.
And by the way, if you see some way (Gel? Fibres?) to make an unsaturated oil solid in a pastry but nicely fluid in the eater's arteries and veins (hence downstream the stomach's acid), please do it! Pastries take saturated fats just to be solid.
Comments welcome, of course and obviously!
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I cannot comment about whether hydrogens can be removed from saturated fatty acids to make them unsaturated by I can give some more context to your topic since i work in the food industry.
First, if it is indeed possible to remove hydrogens with a catalyst, is this specific enough to be able to direct which C-C along the chain you wish to turn to C=C? I would not think so. Typically unsaturated fats are very specific where they have double bonds (eg n3, n6, n9), and may not be metabolized by body if in wrong locations.
The more cis unsaturated (all plant-produced unsaturated fats are cis) the fat the lower will be the melting temperature and thus will likely be termed an oil (liquid at room temp) as opposed to a fat solid at room temp. Fish oil especially from cold waters will have large amounts of omega-3 unsaturated fats with many unsaturated bonds per fatty acid (EPA has 5 & DHA has 6). This allows the fish not to solidify in cold water and why you can't freeze fish oil in the freezer.Trans fats do not have the same kink like cis and therefore can pack more tightly like saturated fats will raise the melting point and tend towards a solid fat. However, trans are much worse for the body since saturated can be used while trans fats cannot and thus can accumulate in arteries and can raise blood pressure and put strain on heart over time. Hence why the food industry is trying to remove as much trans fats as possible.
Typically, margarines were made by partially hydrogenating vegetable oils to the point where the desired melting characteristics were achieved with a platinum catalyst. However this created trans fats since some double bonds bound to catalyst that did not get hydrogenated would release from catalyst but into the energetically more favorable trans form. Becel was the first to have a trans-free margarine using lipases to interesterify blends of soybean (for unsaturated) and palm (for saturated). Now the industry fully hydrogenates soybean oil to become like a solid rock of soy fat and then this gets blended back with soybean oil and can be either interesterified (more expensive but better product) or homogenized together (cheaper but inferior product as oil seepage often occurs) at ratios where the desired melting properties are achieved (ie melts below 37 C but solid & spreadable at room temp, has mostly the more stable beta prime polymorph of fat crystals)
So in my opinion, the most economical way would not be to unsaturate fat by removing hydrogens, but to do what industry is doing already and blending saturated with unsaturated to obtain desired texture and qualities. Palm oil too is fractionated into palm oil (least saturated), palm kernel oil, and fractionated palm kernel oil (most saturated) using a process called winterization, which is simply heat and cold cycles followed by filtering out solid crystals from oil.
Probably much more info than you needed, but perhaps will give more context and generate more conversation.
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In reply to your side note
If cheap enough, it can also run Diesel engines like rapeseed oil does; presently, palm oil's triglycerides are converted in fatty methanol esters to make biodiesel. It would also be a source of hydrogen as a sideproduct.
Why bother to modify the palm oil before making biodiesel ?
Would it be better just to convert the palm oil to biodiesel rather than use it for food?
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Even if we take the rather spurious simplification that all saturated fat = bad for you and all unsaturated fat = good for you, palm oil (~51% saturated) is still better for you than butterfat ( 66% saturated), about equal to beef tallow (53%), but worse than lard (41%). Although, lard has gotten a bad rap in recent years. Plus, it's practically indispensable in a good pie crust. But I digress.
Source: http://www.uccs.edu/Documents/danderso/fats_oils.pdf
Aside from the fact that nutrition is more complicated than that - so I maintain - we are left with a couple of things to consider. First, in poor countries, any long term deleterious effects of consuming a diet high in saturated fats are probably outweighed by the simple need to consume calories from any sources. Is making a healthier oil really so important? So many other more pressing threats to health in developing countries - heart disease seems inconsequential at this stage. It's already hard to get critical drugs to such area, due to logistics and superstitions... imagine trying to get modified food oils, and educating people about why it's good to use them. A minor point is that poor countries tend to be in hot climates, and unsaturated fats have lower shelf life in hot climates. Finally, using hydrogenation to modify food oils for various reasons sounds pretty good at first glance, but it has the unfortunate consequence of generating trans-isomers in unsaturated fats, which are certainly far worse for you than good old "natural" saturated fats. Sometimes it's better off to leave well enough alone.
As a random aside, but not totally irrelevant Enthalpy since you mentioned making pastry with liquid oils, I have a great pastry crust made from olive oil that I like to use when I make quiches. Granted, sometimes you can't beat butter and lard (50:50 mix, no other option, although vegetable shortening works rather well too - and yes that's the only time I'll use it) in a pie crust, but for a healthier option, it's pretty good and you don't feel so bad about yourself afterwards. For that matter, I also use oil when making grilled cheese, and there I can hardly tell the difference. :)
Well, that's some random rambling on the topic from me.
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And another point to add about making oleogels -- some groups are starting to work with oils and small amounts (<2%) of high MW ethyl cellulose, and these can make quite firm gels with low syneresis; however, their texture is radically different than a solidified fat due to increased saturated fat content (no nice melt-in-mouth creamy mouthfeel -- more like a brittle break with the teeth followed by oily mouthfeel)
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Thanks to all and everyone!
My knowledge about nutrition didn't even include that trans fats are worse than unsaturated ones, so dehydrogenating palm oil looks uninteresting for human consumption, that's clearer now. I appreciate the input!
Some enzymes are known to add double bonds at exact locations of a fatty acid (and a triglyceride?). Any chance to use that on a big scale?
To run Diesel engines, I'd keep the triglyceride, just unsaturate palm oil so it gets fluid. The present method makes a methanol ester of it, which corrodes the seals hence works only for some decently recent engines, but only the older Diesel engines (with a pre-chamber like my 1987 Citroen Cx) run on straigth vegetable oil (provided their pump copes with the viscosity).
Gelling a healthy fluid oil for pastries: I won't challenge lard at home - but industrial pastries use palm oil presently, so do chocolates and other food processed at a lower temperature, and palm oil is chosen for being solid and cheap, not really for its taste. So I wonder if a healthier oil could be kept solid somehow, resist the process temperature, but get fluid in the (acid) stomach.
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Gelling a healthy fluid oil for pastries: I won't challenge lard at home - but industrial pastries use palm oil presently, so do chocolates and other food processed at a lower temperature, and palm oil is chosen for being solid and cheap, not really for its taste. So I wonder if a healthier oil could be kept solid somehow, resist the process temperature, but get fluid in the (acid) stomach.
Occasionally I make cupcakes or other iced confections with my daughter. When possible I make the icing myself, using butter typically. But occasionally (busy life of a parent and all) I buy the premade, shelf-stable icing that comes in a can. Unfortunately most of the big brands (like Pillsbury) use hydrogenated vegetable oil as the fat source, which contains trans fats. In fact, it's one of the few products on supermarket shelves where you can actually find trans-fats since FDA made labelling of these compulsory. Thankfully, one of the generic brands at my local grocery store uses beef tallow instead of hydrogenated vegetable oil, so I buy this one almost exclusively. Crisco and other brands of vegetable shortening actually no longer contain trans fats. I'm not sure of the science behind how they do it.* But the fact that icings still have trans fats suggest that these kinds of vegetable oils are still not appropriate for icings. I'm not sure what is the reason for this. Also, if the big food companies haven't found a way to make trans-fat-free hydrogenated fats suitable for icings, then there probably IS some room for invention there.
And of course, there is always Olestra, which honestly I thought was a promising product but became victim to a PR disaster, at least here in the US.
http://en.wikipedia.org/wiki/Olestra
*Pertinent to the thread, it looks like they did it by mostly changing the starting fat source. Crisco used to be made primarily from hydrogenated cottonseed oil (crystallized cottonseed oil, or Crisco). Now it includes a lot of palm oil, which is already solid and satured. Therefore they can keep the trans fat amount low by limiting the amount of hydrogenated oil in the product. Actually, the trans-fats in hydrogenated oils are just side products originating from the catalyst used to hydrogenate the unsaturated fatty acid precursors. It looks like if you could identify a hydrogenation process that reduced or eliminated this unwanted side product, this could be quite a valuable process.
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I don't mean to get off topic, but the research initially done on saturated fats that showed it was bad for you was done with hydrogenated saturated fats which no doubt had transfats in them. Further studies that have been done using better science are inconclusive at best. Also, it's extremely difficult to find good unbiased information about nutrition on the internet.
Here is one study, take it as just that - one study:
http://www.eufic.org/page/en/show/latest-science-news/fftid/Study-no-association-dietary-saturated-fats-cardiovascular-disease-risk/
Unfortunately, it takes a long time for the dogma to shift that perhaps fats are far more complicated as to whether or not they are good for you or not rather than just how saturated or how much trans fat they have. Ironically you can now buy coconut oil in health food stores because it's healthy despite the saturated fat. I'm also starting to see some studies that show that polyunsaturated fats aren't necessarily good for you - we seem to have gone full circle. I am speculating here, but perhaps it's the increased amount of oxidation and generation of free radicals that liquid fats are susceptible to.
So, I'm not sure what my point is other than Corribus is spot on in saying you are better off getting calories into them rather than worrying about what kind of calories. Also there could be some unintended consequences of unsaturating fats - just look at what happened with trans fats.
One more thing - yes, lard is ideal for the best pie crust! Tallow works almost as well.
-d
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Nice of you all, that's a wealth of information...
Just one elementary question: I see the compositions of natural triglycerides given as if each glycerol beared always three times the same fatty acid. Is that true? Does it result from the synthesis process in living organisms? Or do the acids jump and mix between the glycerols, if not at the production place, then in our stomach?
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In general in Earth based organisms - fat has a glycerol portion and 3 fatty acids attached to it. The enzymes available are quite adept at creating and breaking them down. As part of digestion, it is my understanding the that glycerol is broken from the fatty acids and the fatty acids get further broken down.
I'm not sure if you are familiar with Olestra - esterified sucrose. It was synthesized in a lab. Rather than having a glycerol molecule with 3 fatty acid chains, it's sucrose and has about 8 fatty acid chains. Digestive enzymes aren't capable of breaking these apart and it passes through the body without the calories being absorbed. So it seems the enzymes around are only capable of breaking down the ones with glycerol.
I know there are enzymes capable of changing around fatty acids and ones that can break the fatty acids from the glycerol, but I don't know the extent to which this is possible.
I hope this helps.
-d
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Nice of you all, that's a wealth of information...
Just one elementary question: I see the compositions of natural triglycerides given as if each glycerol beared always three times the same fatty acid. Is that true? Does it result from the synthesis process in living organisms? Or do the acids jump and mix between the glycerols, if not at the production place, then in our stomach?
It is common for triglycerides to have all the same three fatty acids (in lipid chemistry, for example, SSS & PPP would denote stearic acid and palmitic acid esterified to all three glycerol hydroxyls - tristearin or tripalmitin). However, they do not need to be. Typically the Sn1 and Sn3 position tend to have the same fatty acid while the Sn2 (center glycerol hydroxyl) will have a different fatty acid, and this tends to be unsaturated (eg. POP, SOS or POS, SOP). There are lipase enzymes specific for the Sn1 & Sn3 positions and different lipases for the Sn2 position. Some fatty acid analysis methods utilize these. In milk, which has the broadest range of fatty acids known in nature including a sizable amount of short chain fatty acids (butyric C4:0, valeric C5:0, caproic C6:0, capryllic C8:0, capric acid C10:0), and the only one known to naturally have odd numbered fatty acid chains (due to microbial fermentation inside cows' rumen before absorption and packaging into milk vesicles), these small chain fatty acids tend to go on the Sn1 with different species on Sn2 and Sn3. There are sort of generalizations but no hard rules.
Here below is a list of the fatty acid positions (Sn1, Sn2, Sn3) and approx content (%) on triglycerides from common food oils & fats. 12:0 is lauric acid, 14:0 is myristic, 16:0 is palmitic & 18:0 is stearic (all saturated), while 18:1 is oleic acid (monounsaturated), 18:2 & 18:3 (linoleic & linolenic, respectively - both polyunsatured) -- these are by far the most common fatty acids bound to triglycerides found in nature.
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi61.tinypic.com%2F334860m.jpg&hash=415b8f5af61ccad5d2ac0c329ac932722e373b53)
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Ah yes, I misunderstood what Enthalpy was asking. Your answer was much better than mine Furanone.
-d
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Never mind Darryl1! As I nearly ignore the topic, I can only learn, hence thanks to all!
And just like lard is best for pie crust, myristic acid is a must for any myristic pizza!
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Nutmeg Pizza?
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I can see using a tiny amount in the crust just under the threshold of realizing it's nutmeg, but that you can realize there is something there.
Although personally, I would think it would be better in a custard pie.
-d
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Just a bizarre thought... Palm oil is reportedly the cheapest one but is quite unhealthy, with a proportion of saturated fatty acids worse than even pork fat.
An interesting topic. I recall Gary Taubes writing a book critical of the data leading to the low fat diet. I also recall an episode of 60 Minutes in which epilepsy patients were fed diets with high fat levels. You can find some interesting data in wikipedia on trans fatty acids. It is interesting to see how food manufacturers are able to adjust different fat contents for different purposed.
I'm not going to go looking for the studies condemning saturated and unsaturated fats, but I am going to be a little skeptical unless someone shows really good and definitive data. I am guessing a diet somewhere between high and low fat may be just right.
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There are different specialty starches out there that can mimic the mouthfeel of fat. I get to play with them all the time for a living :)
I would be skeptical too about most studies out there when it comes to nutrition. After digging through many of them over the years, I find most of them to either make false conclusions or the correlation is so weak that nothing can even be concluded without any sort of follow up. However there are a lot of good studies out there do a good job of raising questions about assumptions that require further study.
My own personal view on how much fat one should consume (or nutrient in general) is that it's going to vary with each individual based on their genetics and their gut flora. I mean you give some overweight individuals a low fat diet, they lose weight, you do that to others and not only do they not lose weight, they are always hungry and get diabetes.
-d
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Here are observations made on a cohort comprising me and myself, followed my my poorly substantiated ramblings - you choose how much credibility you give them.
- After eating much unsaturated fat, like the sauce for an artichoke, I get within 1-2 hours a layer of fluid oil on my skin, especially at the had and ears;
- After eating much bad fat, like cheese or sausage, I get acne within hours, again at the had and ears.
So could the process be as simple as:
- The fats our skin exudes reflect, in amount and composition, what we recently ingested;
- When these fats are thick, they clog the pores and build acne?
Nice: after eating a pizza with cheese and salami, if I swallow two teaspoons of sunflower oil, I don't get acne.
Opinions, observations, experience? Even dissent maybe?
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More ramblings.
Thick fats like cheese or bacon seem poorly soluble in thin fats like olive oil, so if ingested in separated meals, the thick fats will deposit in the arteries and clog them, while thin fats won't dissolve them afterwards.
But if ingested at the same meal, they will swap their fatty acids in the stomach (do they?) to build a set of new fats, rather fluid, that don't clog the arteries.
At least, this is consistent with the so-called "Mediterranean diet". Having lived in Madrid, I testify that Spaniards ingest big amounts of chorizo, queso and jamón, not outweighed by olive oil. But the difference is that they eat significant light fats at most meals, be it over bread or as cooking oil.
The discussion is lighted...
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Varied French sources keep claiming that some wine consumption reduces the incidence of heart attacks. They cite an unspecified "american scientific study" unknown outside France, but stop short of claiming "only true French wine".
So is it just the usual disinformation of the population meant to increase the tax yield and the exports, reduce the imports, and save on the pensions? Maybe not, after all.
Within the logic of my message of 29 July 2017 here, which may very well be flawed, ethanol in the stomach together with triglycerides would catch some fatty acids, leaving less on the glycerine. Glycerol mono and diesters (or possibly chlorides) would be more runny than triglycerides, while ethanol esters are thin anyway. That would avoid thick triglycerides that clog the arteries. Little ethanol by mass would suffice.
That's very much the process to make biodiesel: saponify the too thick palm oil, then make runny esters with methanol.
If ethanol is the efficient component in wine, good Chilean wine will work equally well. Or sake. Or some non-poisonous small mono- or diol.
Eating sugar or their polyol ersatz at the same meal as triglycerides would be unsound, not because they catch some fatty acids, but because they make a bit of much worse esters.