By Renée Gan, Contributing Editor
It is no secret that consumers today are looking for natural ingredients on their food labels—or perhaps more accurately, the absence of chemical-sounding ones. The natural arena is heating up, buoyed by the growing popularity of the locavore and sustainability movements. In a recent release from the Natural Marketing Institute (NMI), Harleysville, PA, “pure and simple” was listed as one of the top trends for the new decade, with “cleaner labeling” and “less is more” specifically cited. This puts the onus on food scientists to develop products without the old stand-by preservative systems.
Tying up free radicals
Oxidation―particularly of fats―can be one of the biggest issues in manufactured foods. Synthetic antioxidants, such as BHA and BHT, are very effective, but not very natural. Therefore, demand for naturally occurring antioxidants is rising.
First, a quick review of the autoxidation reaction: Oxidation occurs when free radicals formed in the initiation step combine with oxygen to form peroxy radicals. These peroxy radicals yield hydroperoxides in the propagation phase.
Antioxidants act by either inhibiting the formation of free radicals in the initiation phase or hindering the free-radical chain reaction in the propagation phase. The majority of the antioxidants in food act as free-radical scavengers, thereby terminating the chain propagation reaction. In addition, synergists scavenge free radicals along with the primary antioxidant, or metal chelators inhibit the formation of free radicals in the initiation step.
A natural against oxidation
Plant-based antioxidants, such as essential oils, tocopherols and extracts, have shown they are able to stand up with the synthetics when it comes to antioxidant and antimicrobial activity. One such example is rosemary extract, which is quickly becoming one of the go-to natural antioxidants because it contains phenolic compounds that can bind free radicals. Commercial applications have shown protective effects similar to that of BHA and BHT. “Specific rosemary extracts can replace synthetic antioxidants in meat applications,” says Jim Bacus, Ph.D., managing partner, Technology Ingredient Solutions LLC, Gainesville, FL. “Carnosic acid is the key indicator for rosemary activity. We evaluated natural pepperoni for 130 days at 36°F, and found that 100 ppm carnosic acid provided the same oxidative inhibition as did a combination of BHA and BHT used at the maximum allowable limit.” Similarly, just 50 ppm carnosic acid was able to protect color stability in fresh pork sausage compared to BHA and BHT.
