Natural anti-oxidants as food preservatives. Natural, healthy, and good for your food. That’s all good for all of us. It just makes sense.
Oxidation profoundly affects the quality of food and shortens its shelf life by adversely affecting its appearance, texture, sensory properties, and nutritive value. All major food components are susceptible to oxidation, resulting in changes in flavor and aroma (lipids), texture and functionality (proteins), and loss of nutritive value (vitamins). In addition, the oxidation of pigments results in degradation of color and visual appeal and diminished product marketability. It is, therefore, extremely important to find effective solutions for prevention of oxidation processes in foods.
Long before the emergence of the modern food industry, the Native Americans made use of natural antioxidant ingredients in pemmican – a mixture consisting of dried red meat and blueberries or bilberries. The antioxidants from berries were effective in preventing meat oxidation and rancidity for months, without significant losses in quality. Since these early times, the use of natural antioxidants has evolved and become a trend of its own.
Natural antioxidants have a long history of use in various industrial applications. In the late 19th and 20th centuries, extensive research was concentrated on their use in vulcanization of rubber, fuel polymerization, and prevention of metal corrosion.1 In the food industry, early uses were focused on their utilization in prevention of lipid peroxidation and rancidity of meat. In the mid-1970s and 1980s, consumers turned to natural antioxidant ingredients and clean labels, due to skepticism about the effects of synthetic food additives on health. Since the 1980s, the demand for natural antioxidant ingredients has been on the rise.
The results of a recently conducted representative phone survey of 1,004 US adults, 50% of whom were women, pointed to the consumer demand for more natural, environmentally friendly and socially-responsible foods.2 Research has also shown that consumers are willing to pay a price premium for the health promoting properties of organic produce, such as tomato.3
The 2010 USDA database of food ORAC values was one of the first public references on the antioxidant value of food ingredients. It included ORAC values for 277 ingredients: spices, seeds, berries, and other whole food ingredients. Although the original database was withdrawn due to misuse, ORAC testing is still performed today in conjuction with more comprehensive in vitro and in vivo analyses and clinical studies.
Some examples of potent natural antioxidants and their sources include: tocopherols (nuts and seeds), ascorbic and citric acids (citrus fruits), carotenoids (fruits and vegetables) and phenolic compounds (herbs and spices, grape seeds). Plant phenolic extracts are often used in preservation of seafood, meat, fats and oils. Ascorbic acid is used in preservation of juices, cereals, jams, cured meats and some canned foods, while tocopherols found their applications in preservation of cereals, meat and poultry products, butter, oils, and dairy products.
Rosemary extract is the dominant natural extract in Europe and the US. It is derived from the Mediterranean herb Rosmarinus officinalis and used effectively in both oil and aqueous applications – in vegetable oils, butter, baked goods, fried foods, meats and beverages. The main active constituents of rosemary extracts are carnosol, and carnosic and rosmarinic acids, which are highly effective radical scavengers that may act in synergy with other antioxidants: tocopherols, ascorbic and citric acids.4
Several important factors must be considered in utilizing natural antioxidants as food preservatives. They are typically more expensive than synthetic antioxidants because they have to be extracted and purified from botanical sources, often in large quantities. In addition, special attention must be given to their impact on palatability, aroma, and color of the final product. Moreover, their solubility and stability must be addressed. For example, mixed tocopherols are resistant to high temperature food processing steps, have low volatility, and are soluble in fats and oils, which makes them suitable for use in baked goods, cereals, nuts, and meat and egg products.
The FDA regulates the permitted uses and dosages for both natural and synthetic food preservatives. Some herb and spice extracts have GRAS (Generally Recognized As Safe) status, which makes them appealing to consumers. Others are considered to be indirect additives and the solvents permitted in the extraction process, as well as remaining solvent levels, are specified.4 Finally, concentrates and resins are regulated by the FDA as dietary ingredients under the ‘’Dietary Supplement Health and Education Act of 1994’’. Important regulatory guidelines must be followed for a successful launch of a new product containing a natural antioxidant.
- 1. Mattill HA. Antioxidants. Annu. Rev. Bioch. 1947;16:177–92.
- 2. Food Labels Survey, 2014. http://www.greenerchoices.org/pdf/ConsumerReportsFoodLabelingSurveyJune2014.pdf
- 3. Defrancesco E, Trestini S. Consumers’ willingness to pay for the health promoting properties of organic fresh tomato. Rivista di Economia Agraria. 2008;63(4):517–45.
- 4. Brewer MS. Natural antioxidants: Sources, compounds, mechanisms of action, and potential applications. Comp Rev Food Sci F. 2011;10:221-247.
Jasenka Piljac Zegarac is a scientist and freelance writer. She holds a PhD in biology and a BS degree in biochemistry, and contributes on a regular basis to several health and science blogs. She may be contacted for assistance with a variety of science and medical writing projects. You van find Jasenka on LinkedIn.