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The conflicting life of animal fat

Posted: Thu Oct 06, 2011 23:29
by story28
Animal fat is a well known preservative for preparations like duck confit, pemmican, or as a seal for preserving crocks of rillettes.

Animal fat is also known to promote spoilage by causing products to go rancid, such as beef jerky, dried sausages, and the like.

I was wondering if anyone here on the forum knows the scientific facts and the molecular activity behind this duality?

Posted: Fri Oct 07, 2011 00:33
by JerBear
I really don't know the science but at first blush it would look like assumed storage. At least as far as the confit and rillets the product was designed to be held in cold-storage such as a basement, cave or pantry. The pemmican was more of an on-the-go food and I assume that heat would likely be a concern. I found a couple "traditional" recipes online and one mentioned smoking (which I'm not really sure is that accurate) but another specified that there should be no remaining water in the product. That makes sense as the case of the rillets and confit most of the water would be removed in the cooking and substituted with fat then sealed with fat. Water is needed by nasty microbes to grow.

That leads to the "dried" sausage and jerky which in actually are not fully dried and have a sufficient amount of remaining water to be a concern. But to clarify we're talking about products that don't have added nitrates. I could be talking a bit out of my backside as it were but this is what makes sense to me.

Posted: Fri Oct 07, 2011 02:49
by ssorllih
I save surplus pork fat for cooking and often find leftover pieces of well done meat in the fat matrix. The meat in this instance is quite dry kept cold and protected from the oxygen.

Posted: Sat Mar 17, 2012 10:28
by Chuckwagon
Well Jason my boy, you`ve opened a can of worms here. Geeeze, it's only been six months since you asked this question. I'd like to have a crack at the answer anyway. I'm surely no expert, but shucks, you can always throw tomatoes at me if you don`t like my answer.

Deterioration of lipids has always been a significant problem in the storage of oils and fats wherever sausage makers are concerned. I wonder how much has been thrown out and just how many folks have been sickened by the degradation process in lipids. The natural process of decomposition or degradation, has often been called rancidity and is the hydrolysis or oxidation (or both) of oil or fat. The increase of rancidity is associated with by a discernible increase in the acid value of fat, normally tested using two basic laboratory tests: Peroxide Value (PV) and Anisidine Value (AnV).
Reacting with air or moisture (and/or other elements), the process of degradation converts fatty acid esters of oils into free fatty acids. Triglycerides (95 percent of all dietary fats), are included and are naturally occurring esters of three fatty acids and glycerol. By the way, doctors will tell you that heart attack victims have high triglycerides... but will not say that those having high triglycerides will have heart attacks. :shock:

Some oils, such as conjugated linoleic acid (CLA) or saw palmetto, are naturally high in free fatty acids. The degradation of these lipids become so severe, that they eventually reach the point of becoming either unpalatable or unhealthy to ingest, indeed being linked with the development or. Ingestion of rancid lipids has been linked to the development or intensification of such diseases as atherosclerosis, cataracts, diarrhea, kidney disease and heart disease. Worse, they can cause cellular membrane damage, neurodegeneration, and carcinogenesis.

Ok pard, which of the oils would you think would turn rancid more quickly? Believe it or not, vegetable oils tend to be less stable and turn rancid more quickly than do animal fats. Not only that but they can also become several times more rancid than animal fats. Almost unbelievably this may occur before the human sense of smell can detect it! Unsaturated fats are more susceptible to oxidation than are saturated fats. This means that the more polyunsaturated a fat is, the sooner it will become rancid. Why? It`s due to having more unstable double bonds, which allow more oxygen to react at those points. Now any cowboy worth his salt would say, "that`s catawampously exfluncticatin"!

Oils slowly become more oxidized over time - they don`t suddenly become rancid. And just what causes rancidity in stored edible oil? If it is oxidative the process is known as autoxidation and it occurs when oxygen is absorbed from the environment. Also, in the presence of UV (ultraviolet radiation), most lipids will break down, degrade, and form other compounds. Ok, now get this... oxygen is eight times more soluble in fats than it is in water. No kidding! This exposure is the main cause of the autoxidation process, increasing the saturation of the oil.

If the rancidity is hydrolytic rather than oxidative, the process is called hydrolysis or "enzymatic oxidation" and it occurs in the absence of air yet having moisture present. This is normally accomplished through something the big guys call "enzymatic peroxidation". OOOoooo :roll: Wow, did you get that? Oh, stop worrying. It just means that it takes place where enzymes are found naturally in plant oils. Examples are lipoxygenase and cyclooxygenase. In animal fats, the enzyme lipase may catalyze reactions between water and oil.

Whoa hoss! There`s one more degradation process - microbial rancidity. This process takes place whenever micro-organisms such as bacteria, molds and yeast use their enzymes to break down chemical structures in oil, producing unwanted odors and flavors. Sound familiar sausage makers? Do you remember Brocotrix Thermosphacta? In this type reaction, water needs to be present for microbial growth to occur.

What controls the speed and severity of the degradation or "rancidity" processes? It all depends upon elements of nature including temperature, time, light, water, and catalysts. Light? Yes, in the presence of oxygen, light promotes oxidation of unsaturated fatty acids. And what catalysts? Hmmmm, that would be trace metal ions, metalloproteins, and inorganic salts. You know... "catalysts" :wink:

How does it all take place? Lipid peroxidation, the oxidative deterioration of unsaturated fatty acids, occurs in three phases. The first, "induction" phase takes place when unsaturated fatty acids combine with molecular oxygen to produce hydroperoxides and peroxyl free radicals - both highly unstable and most reactive. Next, "propagation" takes place where these unstable free radicals react with other lipids to initiate a continuing "free radical lipid peroxidative chain", if you will. Whew! This is autoxidation and results in a continuing or cyclical oxidative degradation process, breaking down the lipid.

Are you following me Jason? Pay attention! Quiz at 5:30! C'mon... There`s only one more process to go. :roll: The final phase is "termination" and it`s recognized by the slowing and stoppage of the other reactions, completing the formation of unreactive compounds such as amides, aldehyedes, hydrocarbons, alcohols, keytones, etc., whenever an antioxidant is either added or encountered.

Ok, it gets a little "hinky" from here. BTW, did you see "The Fugitive"? Tommy Lee Jones (Inspector Girard) told Cosmo that he wouldn`t talk to anyone who used the word "hinky". :???: Anyway for further information about primary oxidation byproducts, including peroxides (ROO) and hydroperoxides (ROOH) or secondary oxidation products occurring when ROOH further degrades into other substances, I recommend a qualified course of study. This is where the stuff becomes volatile, including various acidic compounds. Interesting stuff in all. Over time, these compounds have been known to start fires upon reaching "auto-ignition" temperature and condition. In other words, clean up all your old messes and rags!

A completely separate topic may be mentioned here. It is how to measure rancidity. Again, a course of study would reveal measurements incorporating units of milliequivalents (meq), normally reported as millimole (mmol) of hydroperoxide. Yikes! Did you get that? The boys who discuss that stuff won`t even speak to me! What the heck - my horse won`t speak to me either. Come to think of it, some of those boys remind me of the back end of my hoss!

Best Wishes,

Posted: Sat Mar 17, 2012 14:41
by ssorllih
CW , An excellant essay. Thank you. It begs another question. Will the use of fat replacer using vegatable oil shorten the shelf life of sausages made using fat replacer?

Posted: Sun Mar 18, 2012 01:13
by Chuckwagon
Thanks Ross,
"Fat Replacer" is a product of the Sausagemakerâ„¢ in Buffalo, N.Y. and consists of konjac flour, xanthan, and microcrystalline cellulose. Fat Replacerâ„¢ has just a bit of a problem dissolving completely in water because microcrystalline cellulose particles do not readily dissolve - although konjac flour will. This is the reason the product comes to us in dry powdered form to be mixed directly into the meat mass. Once the fat replacer becomes moistened in the mixture, it becomes slippery, simulating the texture and mouth-feel of fat. With the use of fat replacer, there is no need to add oil of any kind.

Posted: Sun Mar 18, 2012 02:26
by ssorllih
I thought that there was a product that uses veggie oil, water and some manner of dry solid that was mixed to form a fat substitute. Ah! got it now, soy protein isolate, water and oil emulsion.
I was mis-using trade names.
So my question remains will the use of veggie oil in place of animal fat adversely affect shelf life?

Posted: Sun Mar 18, 2012 05:38
by Chuckwagon
Ah Haa, :cool: You are talking about "oil emulsion". Yes, it begins to break down in about 5 days even refrigerated. However, that is a small enough annoyance considering the profound benefits of the stuff. Allow me to quote from Stan`s book, "Making Healthy Sausages" on page 154.
"Replacing animal fat with vegetable oil delivers good results, eliminates much cholesterol and lowers calories. It is not easy to manually mix oil with meat, and some extra water. It often results in poor binding and the texture may crumble. Using pre-mixed oil emulsion provides the best texture and is strongly recommended. Such an emulsion is easily made from soy protein isolate, vegetable oil, and water. It has a consistency of a soft cream cheese, it is a white gel that looks and tastes like fat."

The recommended formula for making the emulsion is soy protein isolate, vegetable oil, and water, in the ratio of 1:4:5. Don`t confuse soy protein isolate with soy protein concentrate. The emulsion will not work using SPC which is only about 70% protein as opposed to about 90% found in SPI (soy protein isolate) which may be found in health food stores.

For some reason, people have been hesitant to make the emulsion at home for use in sausages although most of us have had it in store-bought and commercially processed sausage at one time or another. I don`t know why we are so diffident ... it contains ZERO cholesterol! It also has far less than half the calories compared to fat. For instance, one hundred grams of fat contains 900 calories. Yuk! One hundred grams of emulsion contains only 398 calories. And the stuff even tastes like fat with the texture and mouthfeel of the real thing.

How do we make it? Simple. Use a food processor. Measure out all three ingredients and have them ready. Chill the oil. Add the water and soy protein isolate and mix them together for about one minute until a shiny paste forms. Finally, blend in the chilled vegetable oil at a high speed until the emulsion forms in about two minutes. Refrigerate it in a glass container up to 5 days.

Best Wishes,

Posted: Sun Mar 18, 2012 06:07
by story28
CW, you are the best. I am definitely reading this one thoroughly twice. The only thing is, I have to do so in the morning. This shop is kickin' my arse with 21 hour days; just to keep up with the demand. It is nothing short of insane.

People are loving the CW "Old-World Craftsmanship" stamped on the bag though :smile:

Posted: Sun Mar 18, 2012 06:16
by Oxide
Chuckwagon wrote:
The recommended formula for making the emulsion is soy protein isolate, vegetable oil, and water, in the ratio of 1:4:5. Don`t confuse soy protein isolate with soy protein concentrate.

(a) can pea protein be substituted for soy bean protein? (Pea protein is organic, soy bean protein is GMO. GMO or not, soy beans may not be a good idea for protein.)

(b) anyone that is serious about making Italian food knows that olive oil and water will bind and make a creamy sauce like melted butter (fat) for pasta.

Your dissertation on 'fat' was excellent reading. I waited until everyone was out of the house so I could look like I knew what you were talking about. :mrgreen:

Btw, can you explain why chicken fat melts at 75 F, but chickens have a body temp of 102 F ???

Posted: Sun Mar 18, 2012 06:19
by Chuckwagon
This shop is kickin' my arse with 21 hour days; just to keep up with the demand. It is nothing short of insane.
Jason, my boy... if anyone can make that business succeed, it will be you and Carolina. Be sure to get enough rest each day and eat all your brocolli! :lol:

Yer ol' adopted dad,

Posted: Sun Mar 18, 2012 14:04
by ssorllih
Jason, Don't hesitate to hire some part time help. If just for clean up and stock storage. The logistics of running a busy shop must be very complex. Just a sign in the window for a stock boy/girl wanted will get you some help at minimum wage and a kid that will be pleased to have some work.
I am truly impressed with the response you are getting. Don't let it kill you.

Posted: Mon Mar 19, 2012 05:24
by story28
Thanks for the encouragement guys! I don't mean to spam up this great thread with my narcissism so I will just say that your support is very appreciated. It helped get me through our first Sunday.