Natural carotenoids like zeaxanthin may extend the shelf-life of refrigerated sausages and allow formulators to remove artificial preservatives to tap consumer trends, says a new study.
Sausages formulated with zeaxanthin and norbixin were found to reduce levels of oxidation products, indicating reduced spoilage after refrigerated storage for 45 days, according to findings published in Meat Science.
Furthermore, the natural pigments performed significantly better than the synthetic preservative sodium erythorbate (NaEry), reported the researchers from the University of Campinas and the University of São Paulo in Brazil, and the University of Massachusetts, Amherst.
“It might be suggested that in a meat emulsion, a great part of the oxidation occurs at the surface of the oil droplet or membrane lipid. Polar compounds, such as NaEry, tend to locate in the continuous aqueous phase, while very apolar ones, such as beta-carotene and lycopene, preferentially locate inside the oil droplets,” report the researchers.
“Norbixin and zeaxanthin, the carotenoids that showed the best antioxidant activity, are more polar than beta-carotene and lycopene, and would tend to locate near the emulsions droplet interface or phospholipid membrane, exactly where oxidation seems to be more prevalent,” they added.
Oxidation processes in food can lead to organoleptic deterioration in taste, colour and texture. The food industry has long been aware of this, and is increasingly seeking natural solutions rather than artificial additives, such as like sodium erythorbate (NaEry), butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT), to extend the shelf life of milder-tasting products.
According to a 2003 report by Frost and Sullivan, the synthetic antioxidant market is in decline, while natural antioxidants, such as herb extracts, tocopherols (vitamin E) and ascorbates (vitamin C) are growing, pushed by consumer desire acceptance and easier market access.
The Brazilian and American scientists produced six sausage formulations with sodium erythorbate, norbixin, lycopene, zeaxanthin, beta-carotene, or dextrose at a level of 0.05 grams per 100 grams.
Following refrigerated storage for 45 days, oxidative stability was determined by measuring levels of MDA (malondialdehyde), a reactive carbonyl compound and a major end product of lipid oxidation. Results showed that zeaxanthin and norbixin were the most effective, while no effect was observed for sodium erythorbate.
“Although all pigments were able to preserve the oxidative stability of the sausages stored at 4 degrees Celsius for 45 days, zeaxanthin and norbixin seemed to be the most efficient antioxidants when MDA equivalents were used as the oxidation marker,” wrote the researchers.
“This can be associated with the intermediate polarities and locations in the emulsion interface of both zeaxanthin and norbixin. Other volatile secondary oxidation products besides MDA should be evaluated in further studies involving natural pigments and sensory stability,” they concluded.
Source: Meat Science
Published online ahead of print, doi:
“Effect of natural pigments on the oxidative stability of sausages stored under refrigeration”
Authors: A.Z. Mercadante, C.D. Capitani, E.A. Decker, I.A. Castro