Heterocyclic Amines and Carbohydrates

[freeztar]

I read an article earlier today that suggested adding wheat bran to hamburger meat to prevent the formation of heterocyclic amines (HA) during grilling.

 

So, I went looking to find out why wheat germ helps and what it does exactly. I found this journal article abstract.

 

The influence of the addition of carbohydrates with different physicochemical properties on weight loss and formation of heterocyclic amines (HAs) during the frying of beef burgers was examined.

...

The formation of HAs could be correlated to depend on both the weight loss and the type of the added carbohydrate. Of the 11 different carbohydrates tested, raw potato starch was most capable of inhibiting the formation of HAs, while potato fiber gave the lowest weight loss and a comparably low amount of PhIP. Wheat bran and potato fiber were found to reversibly bind HAs. It is concluded that adding small amounts of certain carbohydrates may be a simple and effective way of reducing the amount of HAs and can easily be applied in households and commercial preparations of beef burgers.

 

What do they mean by the part highlighted above? 'Reversably bind'? Is that good?

 

Any other info the chemists can impart related to this is appreciated.

[freeztar]

Subtle bump...

[skittlesmonkey]

yep it happens and you should avoid them but im my opinion Nitrosamines are a much grater danger. meat that is bbq-ed and has sodium nitrite in it makes these Nitrosamines . they are great at causing cancer, and really many times esp in the usa when u buy those turkey legs and they are well cooked but still strangely red inside. bingo. it was banned in europe ages age but not in this waste land. so don't eat anything that has sodium nitride or pickling salt in it that is also bbq-ed or smoked , u can usually tell when its redder than it should be based on how well its cooked.

[freeztar]

Thanks for the info. Do you have some sources that support this?

[Michaelangelica]

Wheat bran and potato fiber were found to reversibly bind HAs.

Sounds like they bind to HAs but this process can be reversed?

[maikeru]

Thanks for the info. Do you have some sources that support this?

 

Sodium nitrite is much of the reason why ham has its distinctive pink/reddish color:

 

Nitrite in Meat

 

Sodium nitrite, rather than sodium nitrate, is most commonly used for curing (although in some products, such as country ham, sodium nitrate is used because of the long aging period). In a series of normal reactions, nitrite is converted to nitric oxide. Nitric oxide combines with myoglobin, the pigment responsible for the natural red color of uncured meat. They form nitric oxide myoglobin, which is a deep red color (as in uncooked dry sausage) that changes to the characteristic bright pink normally associated with cured and smoked meat (such as wieners and ham) when heated during the smoking process.

 

In the 1970s, newspaper articles discussed the safety of meat products cured with nitrite. Under certain conditions not yet fully understood, the natural breakdown products of proteins known as amines can combine with nitrites to form compounds known as nitrosamines. There are many different types of nitrosamines, most of which are known carcinogens in test animals.

[maikeru]

I read an article earlier today that suggested adding wheat bran to hamburger meat to prevent the formation of heterocyclic amines (HA) during grilling.

 

So, I went looking to find out why wheat germ helps and what it does exactly. I found this journal article abstract.

 

 

 

What do they mean by the part highlighted above? 'Reversably bind'? Is that good?

 

Any other info the chemists can impart related to this is appreciated. :)

 

It might be related to amino/protein-sugar adducts and cross-links, such as those that form in Maillard reactions, or something similar but weaker with transient interactions and binding.

 

Browning: The Dark Side of Sugar

Maillard reaction - Wikipedia, the free encyclopedia

 

Under high temperatures, starches can breakdown into sugars, and these reducing sugars can react with amino acids or proteins to form Maillard reaction products. This might help soak up excess heterocyclic amines or nitrosamines, etc. Note that the articles I linked to say "irreversible binding" but this is under the assumption that these products are forming in the body, but if one takes into account they might be forming under very high temperatures in cooking, baking, or BBQing, where all sorts of chemical reactions and bonds are being made and broken, maybe they'd be more "reversible"?

 

I once wrote a report on Maillard reactions and how they related to immune impairment and diabetes for one of my microbiology courses...but that was a long time ago. It was fascinating, but a little over my head at that time.

 

UncleAl the chemistry god would probably be able to answer this better and more authoritatively.

[modest]

I don't know why it says "reversibly bind" rather than just saying "bind". The idea, I would guess, is to bind the HAs to something which would keep it from reacting with organs and whatnot until it's excreted from the body. An atkins-like diet would have no fiber or starches that HAs would bind to, so presumably they are free to roam around the stomach and intestine causing cancer.

 

Here is a rather technical paper talking about binding HAs. The quoted part is at the end, right before 'acknowledgments':

 

Casein micelles are clotted in an acidic stomach, and this protein is subsequently digested in a neutral digestive canal. Through these processes, caseins are changed to water-soluble peptides and then absorbed. If water-soluble protein or peptide can bind mutagenic substances and transport them from the beginning of the small intestine to the large intestine, other materials—such as various fibers or microorganisms in the large intestine—could accept the mutagenic substances and excrete them outside the host body. If these assumptions are true, milk and dairy products could perform an antimutagenic function in vivo.

http://jds.fass.org/cgi/reprint/75/4/958.pdf

 

And this, I think, explains it:

“The body converts heterocyclic amines into a water-soluble form that can be excreted,” says Kulp. “The reactive compounds formed in this process can attach to DNA and cause mutations that are believed to lead to cancer. In addition to the cell damage caused through this pathway, we’ve also discovered that PhIP [a type of HA] binds directly to the estrogen receptor and may play a role in regulating cell growth.”

https://www-pls.llnl.gov/?url=science_and_technology-life_sciences-cancer_diet

So, the normal process of digestion converts HAs into a water-soluble form that then has the potential to cause damage. Any substance that would bind the HAs so they aren't in solution during digestion would presumably keep them from doing damage.

 

I certainly could be wrong, but that's how it reads to me.

 

~modest