Food Product Design: Applications - April 2005 - Antioxidants “Meat” Needs

April 2005

Antioxidants "Meat" Needs

By Cindy HazenContributing Editor

The average consumer might not know BHA from BHT, much less why they might be added to meat, but chances are they are familiar with the term "antioxidant." Health-conscious individuals routinely take antioxidant vitamins such as C and E to scavenge those nasty free radicals that can cause cell damage leading to illness and disease. Not surprisingly, free radicals can wreak havoc in other animals as well as in humans. In meat products, free radical production leads to lipid oxidation, resulting in flavors often described as rancid, warmed over, stale, or "like cardboard." It also causes the color of the meat to change to a less-desirable hue.

The oxidation mechanism has three stages. In the initiation phase, the hydroperoxides present in lipids decompose and release peroxyl free radicals. A series of chain reactions follows in the propagation phase. A hydrogen atom from a lipid binds to the peroxyl radical and forms a more-stable hydroperoxide and a new, unstable fatty radical. This free radical, in turn, reacts with oxygen to form another new peroxyl free radical. The process repeats again and again, leading to permanent, and unfavorable, organoleptic changes in meats.

Additionally, the decomposition of peroxides produces aldehydes and ketones and these, too, contribute to degradation of the meat. The degenerative process continues until the termination phase, when either two unstable free radicals react, or when a fatty radical reacts with an antioxidant radical. In either case, the radical becomes more stable, and the chain reaction is stopped or delayed.

Many antioxidants work by terminating the cycle of free-radical destruction. These chain-breaking, free-radical scavengers often are referred to as primary antioxidants. Others, such as citric acid and ascorbyl palmitate, bind oxygen. These oxygen quenchers are considered secondary antioxidants. Frequently, they are called synergists because they enhance the effect of the primary antioxidant by removing oxygen from the auto-oxidative process. Synergists also sequester trace minerals, averting them from catalyzing peroxides to aldehydes and ketones.

Although antioxidants can bind the radicals quickly, before the damaging chain reaction begins, they cannot undo damage once it has occurred. The key, then, for the food technologist, is to add the proper antioxidant to a meat product before the free radical oxidation process can take hold.

Antioxidant options The marketplace offers solutions ranging from synthetic to natural, but how does one choose the most appropriate antioxidant for a given product? Haresh Madeka, Ph.D., technical services manager, DSM Nutritional Products, Inc., Belvidere, NJ, suggests beginning with two questions: "What is the target shelf life that you are looking for?" and then "Why would it not be achieved?"

A word of caution: Oxidative reactions in meat should not be confused with other spoilage problems such as microbial or enzymatic degradation, however, realizing optimum shelf life takes a multifaceted approach.

Connie Sandusky, Ph.D., director of marketing, Herbalox® Seasoning, Kalsec®, Inc., Kalamazoo, MI, says, "It's very important to have an understanding of meat when determining how an ingredient can be used. An ingredient solution is just one component of managing oxidation. At Kalsec, we talk about it in terms of oxidation management because it's not simply an ingredient solution it's problem solving. You must also consider the quality of the raw materials and you need to make sure that your processes are not creating damage."

Some shelf life problems can be minimized simply by more efficient handling of quality raw materials, Sandusky says. Processing parameters and packaging have to be considered. "Temperature control is incredibly important," she says, noting that the method used to freeze a product can be as important as the way temperature is controlled during distribution. She stresses that when adding an oxidation inhibitor, it should be added as early as possible in the process of making a product. "Then you are managing the quality of the raw materials through the process," she says.

It is worth noting that different meat sources have varied susceptibility to oxidation because less-saturated fats are more easily oxidized. Lean meats, such as pork and poultry, are more susceptible to oxidation than beef. Unsaturated fatty acids are more susceptible to oxidation.

In deciding which antioxidant to use, Madeka says product designers must decide whether to use a natural or a synthetic antioxidant. They must consider labeling and regulatory compliance, as well as ingredient cost.

Lisa Davis, development chemist, Cognis Nutrition & Health, LaGrange, IL, says the technologist also should consider ease of use, whether that means water-dispersible products, oil-based products, or dry powders. Also, think about sensory contributions: Will the antioxidant add flavor, odor or color to the meat? Lastly, is it important that the antioxidant be kosher?

Of all these considerations, perhaps none is more important than regulatory. USDA is very precise in its definitions of antioxidants and the amounts used in specific meat products. What's more, the agency also defines whether antioxidants can be used in combination with one another, or with other ingredients.

Synthetic solutions Tom Carter, technologist, Eastman Chemical Company, Kingsport, TN, explains that four main synthetic antioxidants are on the market today: TBHQ (tertiary-butylhydroquinone), BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene) and propyl gallate. "BHA and BHT are two of the most effective at controlling the oxidation of animal fats. Used in combination, they are particularly beneficial," he says.

Federal regulations dictate that BHA, BHT and propyl gallate can be added to: fresh pork; brown-and-serve sausages; fresh Italian sausages; pregrilled beef patties; fresh sausage made from beef, or beef and pork; cooked or raw pizza topping; cooked meatballs; and various poultry products, at 0.01% of the fat content. They can be used at 0.02% in combination with other antioxidants in meat. TBHQ can be added at the same levels in these meat products, however it can only be used in combination with BHA and BHT.

Synthetic antioxidants are derived from petroleum-based products, but Carter cautions that although they might share similar origins, they are not alike. "It is recommended food processors look for the antioxidant that provides the best protection and is most suitable for their application," he says. "To guarantee product purity and safety, it is important to ensure that synthetic antioxidants are manufactured under GMP (good manufacturing practices) and meet the specifications listed in the Food Chemicals Codex."

Although natural antioxidants certainly have an important role to play in ensuring food quality, synthetic antioxidants have some distinct advantages. "Synthetic antioxidants are easier to use, more reliable, and generally more cost-effective than natural antioxidants," Carter says. "To maintain brand loyalty and integrity, reliability should be a key consideration. Brand owners can assure consumers of consistency of quality of their food products by adhering to regulations for meat and meat products as established by the USDA and other regulatory agencies."

Natural advantage The most obvious benefit of a natural versus a synthetic antioxidant is that the natural provides a cleaner ingredient statement. While this is less a concern for foodservice applications, there is another reason why certain products in this category can profit from a natural option rosemary extract. Rosemary extract is valuable because it is a natural flavor with antioxidant properties. Thus, it can enhance shelf life without being subject to USDA antioxidant regulations, and product designers can combine it with other antioxidants.

Sandusky notes that often, the regulatory level of approved antioxidants is not high enough to protect product life through manufacturing and distribution. "Kalsec's Herbalox Seasoning is a perfect top off solution because it's permitted in all products. There is no upper usage level," she says. "You're limited by what you can afford and its flavor threshold in your product. It's a wonderful solution where the standard of identity limits the amount and types of antioxidant choices. Sometimes people say, 'I don't need to use anything else because I'm already using BHA or BHT in my product,' but the reality is that when you're only in the 100 to 200 ppm range, that's not going to last very long through processing and storage. Herbalox seasoning and rosemary extracts in general are more thermally stable than most synthetics. That probably guarantees that you've got something left to last through the shelf life of the product. Rosemary extracts are particularly effective in deterring meat flavor deterioration (MFD), or what used to be called 'warmed-over flavor. Meat that's been cooked, refrigerated and then reheated, could suffer from MFD and have an unacceptable flavor that is caused by an oxidation reaction."

Rosemary extracts allow different labeling options: They can be labeled "natural flavor" or "extractive of rosemary." "If someone already has natural flavorings or spice extractives on their label, Herbalox Seasoning can be added and no label changes are required," Sandusky says.

Tocopherol treatments "If you compare mixed tocopherols with other antioxidants, they are as good as or better," Madeka says. "They are very potent They are as good as any other antioxidant that you would use."

In terms of labeling, tocopherols have an advantage. "The term tocopherols is becoming more well known among consumers every day, as awareness builds for vitamin E," Davis says. "Another advantage is that because tocopherols are a form of vitamin E, they can add to any vitamin E content that may already be present in the product." However, she notes that care should be taken to ensure that the vitamin E content claim on the nutrition panel reflects the actual alpha tocopherol content after the tocopherols are oxidized in the process of retarding rancidity.

Just as in choosing the ideal form of tocopherols in vitamins, it's important to choose the most-active form for antioxidant activity in meat. Madeka explains the difference: "There are two major kinds of mixed tocopherols, which are classified according to the Food Chemical Codex, the high-alpha and the low-alpha types. The high-alpha type is usually used as a nutrient, because it has a higher vitamin E activity. They are also good antioxidants, but not as good as the low-alpha type. The low-alpha type has a much-higher concentration of gamma and delta tocopherols and a lower concentration of alpha and beta tocopherols. The antioxidant activity of gamma tocopherol is greater than that of delta, beta or alpha tocopherol."

Antioxidant tocopherols generally are called mixed tocopherols. Products with the highest levels of delta and gamma tocopherols will have the highest antioxidant activity. These products are available in liquid, oil, soluble, or dried powder forms. "The powder is more popular among meat formulators," Davis observes. "The most popular way is mixing it in with seasoning or the spice blend. The list of approved meat products includes uncooked or cooked fresh sausages, Italian sausages, meatballs, meat toppings all meat formulations that use a spice blend. That's the most convenient and the most popular way of adding mixed tocopherols."

Another advantage is that tocopherols are very heat stable. "When added to products that undergo some type of high heat processing, they can survive that processing better than synthetic antioxidants, which means less overage and tocopherols product that needs to be added," Davis says. "Synthetics typically have a higher volatility than tocopherols. When exposed to heat, they are going to be even more volatile and vaporize at a higher rate than tocopherols."

USDA dictates the usage rate. Madeka advises: "USDA regulations say that you can use up to 0.03% tocopherols based on the percent of the total fat in processed-meat products, and you cannot use them in combination with any other antioxidants. The same level, 0.03% of the total fat, applies to poultry products as well, but there is an exception. In poultry products, tocopherols can be used in combination with any other antioxidant except TBHQ. However, in combination, no more than 0.02% mixed tocopherols should be used."

It's also important to note that citric acid, which has synergistic antioxidant activity, can be added to meat products containing tocopherols. Davis says: "Tocopherols can be used in combination with citric acid not to exceed 0.01% on the fat basis. Ascorbic acid is a synergist of tocopherols, but the combination has not been approved by the USDA."

On the horizon Although not yet approved for meat products, a couple of ingredients currently being researched are worth mentioning grape seed extract and milk mineral. According to Steve Anderson, vice president, San Joaquin Valley Concentrates, Fresno, CA, "The Department of Defense is looking at grape seed extract as a preservative in meat." If ever there were an extreme test for extended shelf life, it would be soldiers' meals.

According to Anderson, two features of grape seed extract are being investigated: its function as a natural preservative and its healthful antioxidant characteristics. Oligomeric proanthocyanidins are naturally occurring antioxidants concentrated in grape seed extract. Potentially carcinogenic chemicals can develop during cooking. "A proanthocyanidin, or a grape seed extract, will tend to neutralize those cancer characteristics," Anderson says. Grape seed extract has been shown to have numerous health benefits including cytotoxicity toward malignant cancer cells, protection against drug- and chemical-induced multiorgan toxicity, and cardioprotection.

The minerals in milk long have been considered healthful. Daren Cornforth, Ph.D., professor of nutrition and food sciences, Utah State University, Logan, Utah, is studying the antioxidant properties of a mineral extract from milk. "We've shown that it is very effective in cooked meat -- more so than most other antioxidants we've compared it with," he says. "We are using a commercial product called Trucal from Glanbia Foods, Twin Falls, ID. This substance is available as a white freeflowing powder that is 24% by weight calcium and 13.5% phosphorous with some residuallactose, protein and water. It is obtained by drying the ultrafiltered permeate of whey."

For beef and pork, Cornforth suggests usage levels of 1.5% the weight of the raw meat. He recommends 1% for chicken. "I would say it works substantially better than BHT, or butylated hydroxytoluene, at the recommended use level for BHT, which is 0.01% of the fat content of the meat products," he says. "We've found that is a level of BHT that is actually too low for cooked products -- it may work well before cooking, but not after cooking. The milk mineral, at the level we're recommending which is a much higher level, of course, at 1.5% -- works much better than BHT at the level permitted by the USDA. We believe that the negatively charged groups on the phosphates bind ionic iron and prevent the catalytic affect of iron on the lipid oxidation."

Not surprisingly, this milk mineral is a white powder, at a size of less than 7 µm, that would be visible in the meat. Grinding is important to incorporate the product. If applied to ground meat, the powder would be sprinkled on the meat and then reground. "The white particles are not visible after the second grinding," Cornforth says. "It's not something that we're looking to add to steaks or cuts or roasts or injecting in any way. At this time we're strictly looking at the ease of use in a ground meat product. Of course the ground meats are the most susceptible to lipid oxidation anyway so it makes the most sense to put it in a ground meat. We're only looking at items that are precooked and then rewarmed like on a pizza topping or a precooked meatball."

Research is still needed to answer questions regarding consumer acceptability and mineral bioavailability. "The milk mineral contains 25% calcium. That means it could be another advantage, if the calcium would be a bioavailable form that would supplement the calcium in the diet, and this is something (that) needs verification," Cornforth says, noting that how the product might be labeled is speculation. "As far as commercialization, it is still under development," says Cornforth No doubt, as long as man craves meat, he will strive to find better ways to preserve it. Meat is unique, Madeka reminds us: "Vegetable oils have naturally present tocopherols. For example, wheat germ oil has about 0.25% tocopherols," also noting that corn oil contains about 0.1%, and soy oil has about 0.09% -- but animal fats have very little natural antioxidant activity. "In order to protect meat from autoxidation, you need to have some kind of antioxidants in the system."    

Cindy Hazen, a 20-year veteran of the food industry, is a freelance writer based in Memphis, TN. She can be reached at [email protected] .

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