Plant-Derived Natural Antioxidants in Meat and Meat Products

Abstract

The global meat industry is constantly evolving due to changes in consumer preferences, concerns and lifestyles, as well as monetary, geographical, political, cultural and religious factors. Part of this evolution is the introduction of synthetic antioxidants to increase meat and meat products' shelf-life, and reduce meat spoilage due to lipid and protein oxidation. The public perception that natural compounds are safer and healthier per se has motivated the meat industry to replace synthetic antioxidants with plant-derived ones in meat systems. Despite several promising results from in vitro and in situ studies, the effectiveness of plant-derived antioxidants against lipid and protein oxidation has not been fully documented. Moreover, the utility, usability, marketability and potential health benefits of natural antioxidants are not yet fully proven. The present review aims to (i) describe the major chemical groups of plant-derived antioxidants and their courses of action; (ii) present the application of spices, herbs and fruits as antioxidants in meat systems; and (iii) discuss the legislative framework, future trends, challenges and limitations that are expected to shape their acceptance and mass exploitation by the meat industry.

Keywords: antioxidant activity; fruit-derived antioxidants; lipid oxidation; meat; meat-based products; natural antioxidants; protein oxidation; spices and herbs.

Figure 1

Mechanism of lipid oxidation. I: initiation, II: propagation, III: completion, RH: unsaturated fatty acid, ROS: reactive oxygen species, R^●: alkyl radical, RR: non-radical product, ROO^●: peroxide radical, ROOR: organic peroxide, ROOH: hydroperoxides, ^●OOH: hydroperoxyl radical, RO^●: alkoxy radical, ^●OH: hydroxyl radical, O₂: oxygen.

Figure 2

Mechanism of protein oxidation. PH: protein, ^●OH^.: hydroxyl radical, P^●: protein carbon-centered radical, H₂O: water, O₂: oxygen, POO^●: analkylproxyl radical, PO^●: alkoxyl radical, POOH: alkylperoxide, Mⁿ⁺: reduced forms of transition metals (Fe²⁺ or Cu¹⁺), OH⁻¹: hydroxide, POH: hydroxyl derivative, HO₂: hydroperoxyl, H⁺: hydron.

Figure 3

Basic chemical structures of selected phenolic antioxidants. Phenols: (a) phenol, (b) benzoquinone, (c) phenolic acid, (d) acetophenone, (e) phenylacetic acid, (f) hydroxycinnamic acid, (g) 2-phenylpropene, (h) coumarin, (i) chromone, (j) xanthone, (k) naphthoquinone, (l) lignans, (m) stilbene. Tannins: (n) proanthocyanidins, (o) catechin, (p) ellagic acid, (q) gallic acid. Flavonoids: (r) flavone, (s) flavanol, (t) flavanone, (u) isoflavone, (v) flavan-3-ol. Other natural antioxidants: (w) α-tocopherol, (x) β-carotene, (y) lycopene, (z) vitamin C.