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 | | ANTIOXIDANTS: NATURAL OPTIONS | | | International Food Ingredients | | 13/08/2008 | | | Dushka Dimitrijevic, product manager at Vitiva, looks at the difficulties posed by oxidation and how a long-familiar ingredient can provide a natural solution to this age-old problem
All food processors share a common priority: consumer satisfaction, and to meet this they must respond to consumer preference. Increasingly, we are witnessing growing demand for fresh, wholesome and natural food, the result of public awareness that synthetic food additives may not always be the best option.
Producing food that meets all nutritional, organoleptic, hygiene and shelf life requirements, while still being affordable, is not an easy task. Food producers are faced with numerous obstacles throughout the manufacturing process, including: quality of raw materials; microbial spoilage; staling; enzymatic changes; oxidation; and warehouse conditions, to name but a few. Technologies developed over recent years, along with the skillful use of approved additives and processing aids, have made overcoming these problems easier, but obtaining adequate shelf life is still a major concern for many food processors.
So what is the major issue with the shelf life of products, especially those that contain significant amounts of fats and oils, for example meats, deli, frying oils, snacks? The answer is oxidative rancidity.
What is oxidative rancidity?
Oxidative rancidity is often responsible for the off-flavours, off-odours and even off-colours that can develop in many foods. Additionally, it can result in the nutritional value of food being compromised. The change can go so far that rancid food is unfit for consumption, and this triggers financial consequences for producers and consumers alike.
How does oxidative rancidity occur?
Simply put, when food that contains fats and oils reacts with oxygen, irreversible and unpleasant changes occur. This process is increased by heat and light, and catalyzed by metals (i.e. from packaging). Unsaturated fatty acids react with oxygen and form chemical compounds that impart harsh flavors and odours and, once the oxidative reaction is initiated, it progresses at an ever-increasing rate. Time is not on our side in this case but this is not the end of the story.
Oxidative rancidity results in the formation of “free radicals”. As their name suggests. free radicals are molecules that freely interact with other acceptors, including our body cells - and this is what should worry us the most.
Our body cells are a very fine, complex and balanced natural work of art. When undamaged and working properly, our body and mind are healthy. Once damaged by intruders, however, such as free radicals, their function slowly deteriorates or changes, opening the door for a number of diseases. This damage does not occur all at once, rather it slowly and quietly accumulates over time.
What can be done?
Some 50 years ago, the chemical industry came up with an answer to oxidative rancidity – synthetic antioxidants. They were cheap and, at the time, seen as an excellent answer to a long-standing difficulty.
Most of us have never heard of BHA (E 320), BHT (E 321) or TBHQ (E 319), but what we do know is that additives are being put into our food to protect it from spoilage. These additives are widely-used petroleum-based compounds that answer most of our needs for food antioxidants
Their use in food and other applications is limited by government regulations and varies from country to country. BHA and BHT can be used in a concentration of 0.01% maximum in the EU, while TBHQ is banned in Japan. On the other hand, BHT is not allowed in Australia, while the US allows up to 0.02%. These antioxidants can be found in meats, meat products, cereals, deli, snacks, chewing gum, bakery and various other products.
BHT is banned for use in food in Japan (1958), Romania, Sweden, and Australia, while the US has barred it from use in infant foods. However, some food companies have eliminated it from their products altogether, for example McDonald’s in 1986.
While their antioxidant function in food is proven, there are concerns that oxidative characteristics and/or metabolites of BHA and BHT may contribute to carcinogenicity or tumorigenicity. There are also indications that some people may have difficulty metabolizing BHA, BHT and other food additives, which may result in health and behavior changes, for example Attention Deficit Hyperactivity Disorder in children.
Natural antioxidants
Alongside the adoption of synthetic antioxidants another, natural, approach to preventing oxidation has emerged. In fact, nature has produced antioxidants everywhere - it is simply a question of knowing where to find them and how to make the best use of them.
The list of naturally occurring antioxidants is pretty impressive, and includes: vitamin E (tocopherols), vitamin C (L-ascorbic acid), provitamin A (carotenoids), rosemary extract (carnosic and rosmarinic acids), lecithin and a number of others.
Foods that are rich sources of natural antioxidants include berries (blueberries, cranberries, raspberries, strawberries and others), pecans and walnuts, green and white tea, olive and pumpkinseed oils and many more.
Eating food that is rich in natural antioxidants can be highly beneficial to the health, as antioxidants slow down the signs of skin aging, decrease risk of cancer, heart disease and Alzheimer’s. While vitamins E and C are widely used as antioxidants to prevent food rancidity and enjoy the greatest popularity of all the natural antioxidant products, rosemary extract is starting to play an increasingly important role as a powerful source of natural antioxidants.
The rosemary we know
Rosemary - Rosmarinus officinalis – a native to the Mediterranean region, is widely cultivated, including in North America. The genus and common name are derived from the Latin “rosmarinus” meaning “dew of the sea” as the plant grows profusely near the Mediterranean coast where it is sprayed by the sea’s foam.
Long considered a symbol of friendship and loyalty, the fresh and dried leaves are used frequently in traditional Mediterranean cuisine as a herb; especially in chicken- or lamb-based meals. The leaves can be harvested at any time of the year, although they are at their best during the flowering season. Rosemary is a wonderful tonic, particularly for the heart, brain and nervous system. It also stimulates blood circulation, thus heightening concentration, and its active components (carnosic, rosmarinic and ursolic acid) have skin anti-ageing properties. Its bitterness stimulates liver and gallbladder function and aids digestion.
But there is one property that has become particularly important within the food, cosmetic and nutraceutial community - rosemary is a source of very powerful natural antioxidants.
The rosemary we don’t
Although still considered a spice or flavour by the public and regulatory bodies, rosemary is now being recognized and regulated as a natural antioxidant and, as such, is widely used in ever more applications.
Carnosic and rosmarinic acids are active antioxidants and modern science has found ways of concentrating them into more powerful rosemary extracts. Rosemary extracts come in many shapes and forms, including oil and water soluble, liquid and powder forms, with various grades of odour - including odourless - and bitterness. This makes them suitable for various applications in the food, feed, cosmetic and nutraceutical industries.
One of the most promising and beneficial areas of rosemary extract application is in the meat and deli industries. Beyond providing prolonged shelf life and improved sensory attributes, producers can also enjoy rosemary’s benefits of “clean label”.
Research has shown that by adding oil-soluble rosemary extracts to fresh, minced, chilled pork and beef, shelf life can be extended five-fold. If a similar product is used to replace synthetic antioxidants in some sausages, the same extension of shelf life is achieved. Similar positive results have been achieved with hot dog applications, salami, turkey and chicken meat.
Vitiva, which has been researching the benefits of rosemary for over a decade, has developed compounds that impart no additional odour to a product and, moreover, provide clean label benefits. Additionally, rosemary is not known to be an allergen.
What’s next?
Synthetic antioxidant supporters argue that natural antioxidant use has “financial consequences” for which consumers must pay. This is not completely true.
Rosemary antioxidants are highly concentrated, offering powerful tools that can be used at minimal concentrations. This concentration can be as low as 0.02%, which would result in a maximum product price increase of EUR0.02/kg.
www.vitiva.com | |
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