By Donna Berry, Contributing Editor
Long-distance distribution networks and convenience-craving consumers have meat processors exploring methods to extend the shelf life of all types of proteins—from marinated, raw, prepackaged chicken breasts to fully cooked slabs of ribs to simple ground beef. Factor in that an increasing number of consumers seek out labels with terms such as “natural" and “minimally processed," and take a pass on “chemical-sounding" names in the ingredient list, and this dramatically reduces the available options for ensuring product longevity.
“The shelf life of meat products is limited by microbial spoilage and oxidative rancidity," says Kristen Robbins, assistant manager of research and development, Kemin Food Technologies, Des Moines, IA. “Rancidity is responsible for flavor deterioration and color loss, and is also the primary mode of failure for frozen processed meats."
Artificial preservatives such as BHA, BHT and TBHQ have long been the standard to ensure an economically sensible shelf life for fully cooked and packaged meat products. “But today’s consumer is not interested in such alphabet soup," says Rodger Jonas, director, national sales, P.L. Thomas & Co., Morristown, NJ. “They want ingredients that have a clean label and ones that they can recognize."
Plant-based solutions
Many naturally occuring shelf-life extenders can lead a double life. For example, rosemary extract, which is obtained from the bush Rosmarinus officinalis, can be labeled as simply “natural flavor" or “rosemary extract." It is a concentrated source of carnosic acid, a potent antioxidant that slows the development of oxidative rancidity in meat.
To determine antioxidant power rosemary extracts can be standardized by carnosic acid concentration. “Available in powder and liquid form, our rosemary extracts come in a wide range of carnosic-acid concentrations, including 4%, 6%, 15%, 20%, 40% and higher," says Jonas. “They can be dispersed in brine and injected into various meats, or dispersed into a solution with other flavors and topically sprayed onto meats. Another option is to dry-blend the powdered form with seasonings and apply it topically by either tumbling or through a batter. It can also be added directly to the blender, mixer or mincer."
In a shelf-life test, rosemary extract containing 20 ppm of carnosic acid extended the shelf life of ham up to five times the shelf life obtained without any added antioxidant or preservative. “At the same time, there was no change of taste, odor or other organoleptic properties," says Jonas.
Green-tea extract is another natural, plant-derived ingredient that has been shown to delay the onset of oxidative rancidity in meat. Not only does dried green-tea extract contain as much as 40% of the antioxidants classified as catechins, half of which are highly effective epigallocatechin gallate (EGCG), it also contains an array of other compounds that facilitate its antioxidant activities. This includes gallic acid, carotenoids, tocopherols, ascorbic acid and minerals such as chromium, manganese, selenium and zinc.
Studies have shown that certain green-tea extracts work better than to synthetic antioxidants such as BHA. “The high content of catechins in our green-tea extract maintains the fresh quality of many meat applications for longer, with no unpleasant off-flavors," says Jorgen Sorensen, global business director for natural extracts, Danisco, New Century, KS.
Heng Tsang, culinary and meat industry manager, BioActives, a division of Danisco, adds: “Standardization is crucial when dealing with plant-based active ingredients. We show customers that natural extracts can be as effective and dependable as synthetic alternatives." He notes that the company fully standardizes its natural extracts, “thereby guaranteeing customers a consistent product, so they get the performance they expect."
Combinations of green-tea and rosemary extracts are also viable options. “Oxidative rancidity can be delayed in both raw and cooked ground pork when levels as low as 0.2% are incorporated into the product. Warmed-over flavor can also be delayed in cooked ground pork crumbles," says Robbins. “Pork products treated with the green tea–rosemary extract maintain a desirable meaty flavor without adding unwanted herbal or tea-like flavors, as it is highly effective at levels below its flavor threshold.
“Fresh, refrigerated, raw ground pork treated with 0.2% of this green tea–rosemary extract maintained a desirable red color for a significantly longer period of time than untreated meat or pork treated with green-tea extract alone," Robbins adds.
