Talk:Rancidification

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Antioxidant carcinogens?[edit]

Wait wait wait, antioxidants are carcinogens now? what happened to them being -anti- carcinogens that captured free radicals? I also disagree with the sentence: "the chemical anti-oxidants are potential carcinogens". In addition to previous contributor rationale, if chemical antioxidants are used that is because very strict regulated scientific procedures have concluded that they are safe. Subject sentence is at the very least misleading. 84.120.135.112 07:11, 10 October 2005 (UTC)

While most antioxidants will disable known carcinogens, this doesn't mean that antioxidant products are all necessarily benign. They may just as easily cause damage to the body as well, by unbalancing various systems. For all we know, some very well might have carcinogenic properties themselves. Tyciol 23:59, 20 June 2006 (UTC)

The effects of cooking on fats[edit]

As heat accelerates the oxidation reactions that cause fat to go rancid, wouldn't cooking anything with fat in it therefore make the fat inedible? Certain fats seem to be more prone to this than others. From what I can tell, fat oils like olive oil or animal fats are used a lot for cooking, and are stable... do they require higher temperatures or something? This article still doesn't clearly identify exactly what rancidification IS, nor very explicitly the health effects of eating rancid fats. Would rancid fats be comparable or worse than trans-fats or other modified fat products in the diet, for example? Tyciol 23:59, 20 June 2006 (UTC) Also, how does dehydration affect the rancidification of different meats? — Preceding unsigned comment added by Jordnthoms (talkcontribs) 01:59, 10 April 2013 (UTC)

Ratio of antioxidants[edit]

In the sentence "A combination of water-soluble and fat-soluble antioxidants is ideal, usually in the ratio of fat to water" seems to indicate based on its ordering that the ratio used would be the percent of water-soluble antioxidants is directly to proportional to the percent of fat in the food, with the ratio of fat-soluble antioxidants being directly proportional to the percent of water in the food. Is this actually the case, it seems a bit counter-intuitive.

If it's not the case just changing "ratio of fat to water" to agree with the order of the first part of the sentence, "ratio of water to fat" would clear it up.--Jay the Despicable 22:59, 13 April 2007 (UTC)

That's definately a good idea, it seems like a minor mistake in presentation. The only question is which part to flip around. It's probably better to mention fat first, since water-soluble antixodidants are more like a secondary form of protection. Tyciol (talk) 20:53, 12 June 2008 (UTC)

Revision, Christmas 2010[edit]

I was considering revising this article and have already left some pointed comments. My impression (and source) is that rancidification is only about oxidation, which releases small molecules with distinctive smells/flavors. Also it seems that the vitamin E story is not relevent here. But I am open to suggestions and corrections. --Smokefoot (talk) 21:43, 25 December 2010 (UTC)

Why? Oxidation rate is modulated by antioxidants. Well, it (Vit. E) was once as an example of how the body copes with the problem. This rest is a result of some edits. Now, it is not really needed. --Chris.urs-o (talk) 21:57, 25 December 2010 (UTC)
Thanks for the note, I am not sure which of my suggestions your "why" is aimed at. So far as I could tell (I am no super-expert), the current content in this article under the heading "Role of vitamin E" deals with the role of vitamin E as a protective measure in organisms. Tocopherol is used preventing rancidification in inanimate materials such as foods, rendered fats, drying oils. But any info that you might on the subject would be very welcome. My intent here was been to describe the molecular events related to rancidification.
On a related subject, I dont think that hydrolysis of triglycerides or fatty esters is part of the rancidification process. Nor have I heard of "Microbial rancidity" so I am wondering if some earlier editor invented (aka synthesized) this portion of the article as sort of a placeholder.
Comments are welcome.
--Smokefoot (talk) 02:38, 26 December 2010 (UTC)
Enzymes can speed up the rancidification. Ripe salami and ripe fatty cheese have a rancidity. Soap are rancid, but they are boiled. The heading of the Vit. E section is wrong, the equations are very valuable. It is important to know that this chain reaction is exponential. --Chris.urs-o (talk) 05:04, 26 December 2010 (UTC)
Thanks. By "rancidification can be pushed", you mean that enzymes cause rancidification? My impression is that rancidification is an autoxidation, not caused by enzymes. It is a consequence of autoxidation, which can be catalyzed by a variety of agents including degraded metalloenzymes, I guess.
Soap is rancid? Not really, soap is by definition a salt of a fatty acid, period. I guess some soaps prepared from certain unsaturated triglycerides could rancidify, and that aspect might be worth noting.
Also the scheme looks possibly incomplete:
1) The scheme shows hydroxyl radical. There is no ready source of hydroxyl radical, but references are often vague on this point.
2) The scheme shows a monoene. It is the dienes that are very susceptible to rancidification, not mono-alkenes, One source states that one has to heat mono-enes to cause autoxidation. Linolenic and linoleic acid derivatives are the substrates that are likely responsible for rancidification (I need to find other sources to support this impression).
3) The scheme fails to show the important steps. Rancidness is manifested by the formation of volatile organic fragments, but the scheme only shows the formation of the allylic hydroperoxide, before anything interesting happens (hydroperoxides are less volatile than their precursors). The strong flavors/odors arise from the decomposition of the hydroperoxide. Here is a quote from my source: "The intermediate hydroperoxides are labile compounds that decompose into a number of different ... keto compounds,... aldehydes, .... The volatile carbonyl compounds formed in this process are responsible for the taste and odor of oxidized oils and fats."
I won't being doing anything fast, this process takes a while. If you are interested in the topic, drying oils is a relevant article. --Smokefoot (talk) 07:42, 26 December 2010 (UTC)
Autoxidation vs. enzymes, any biological degradation of fatty acids speeds up the chain reaction. Linolenic and linoleic acid derivatives degrade readily under oxygen at room temperature. --Chris.urs-o (talk) 08:36, 26 December 2010 (UTC)
I am not sure what you are saying, complete sentences would help. "Biological degradation" is meaningless - it is the kind of imprecise but plausibly technical phrasing I work against within Wikipedia (although I am guilty of falling into the same groove). Enzymes are completely irrelevant to autoxidation, I am pretty sure. If you have a reference or a direction to read within or outside of Wikipedia, leave a note. Thanks, --Smokefoot (talk) 18:18, 26 December 2010 (UTC)
Ok, sorry. I'm not a lawyer, I never talked much. References are difficult. The chain reaction needs an ignition (hydroxyl radical source), but in nature things are so impure that this is not a problem. In food processing, as in cured meat and ripe cheese the microbial degradation changes the flavor. This rancidity is important there. Anything that degrades the triglicerides, changes its solubility in water and changes the oxygen access. But it wasn't me who included the autoxidation, hydrolysis and microbial degradation division.
About the figure: this figure is available on Wikipedia, pragmatism. --Chris.urs-o (talk) 18:40, 26 December 2010 (UTC)
No problem. Scientists are in fact kinds of lawyers, and become more lawyer-like when the topic of conversation closes in on their area of expertise. Folks walk around with fuzzy impressions about how chemical stuff works and often blame their foggy understanding on biology. But you're right, the autoxidation process needs to be kicked off. Thanks, --Smokefoot (talk) 18:57, 26 December 2010 (UTC)
Note: oils r quite stable. Heats speeds up every chemical reaction, of course. Degradation n emulsification of lipids, freezing n drying of emulsions, speeds up the chain reaction as well. --Chris.urs-o (talk) 17:35, 27 December 2010 (UTC)
The chemical equation was important, the ref was about linoleic acid, and so relevant !!! --Chris.urs-o (talk) 16:23, 30 December 2010 (UTC)

Detergents or cleaning methods[edit]

It would be nice to find referenced material on how to clean gummy rancid oil. Some suggest using sodium-bicarbonate with antigrease detergent to scrub and to later rince with warm vinegar. I've not tried this. Some commercial soaps may also give better results than others (Dawn appears to have some reputation for heavy fat cleaning jobs). Another possible solution could be trisodium phosphate (TSP)... 76.10.128.192 (talk) 03:30, 22 August 2012 (UTC)

photo oxidation[edit]

olive oil is significantly degraded by light 78.149.6.220 (talk) 11:31, 30 July 2013 (UTC)