The application of antioxidants is an effective strategy to mitigate quality deterioration in meat and meat products during production and processing. Plant-derived natural antioxidants are characterized by wide sources, environmental friendliness, safety and excellent antioxidant properties, which satisfy the demand of consumers for healthier meat products. Consequently, they represent a prominent research focus in meat science. Therefore, this article summarizes the mechanisms by which natural antioxidants inhibit lipid, protein and myoglobin oxidation, the application of common natural antioxidants in meat and meat products and their impacts on product quality. The mechanism underlying the effects of plant polyphenols on the structure and functional properties of muscle protein are also summarized. This review aims to provide references for the application of natural antioxidants in the meat industry.

The effect of fat replacement with whey protein isolate-soybean oil pre-emulsions stabilized by ethanol and rutin on the quality of low-fat meatballs was studied. By measuring the emulsion stability, texture, viscosity, particle size and rheological characteristics of pre-emulsions, the best concentration of soybean oil in pre-emulsions was selected. The fat in meatballs was replaced at proportions of 0% (control), 25%, 50%, 75% and 100%, and the best fat replacement proportion was determined by measuring the cooking loss, color difference, texture, volatile compounds, viscosity, and sensory and antioxidant properties. The results showed that the pre-emulsion with soybean oil content of 72% had the best emulsion stability, good gel morphology and the highest viscosity; when the soybean oil concentration exceeded 72%, the particle size of pre-emulsions increased and the elastic modulus decreased. Compared with the control group, the cooking loss, the ΔE value, texture, viscosity and sensory score of meatballs with 25% fat replacement had no significant changes, and the content of off-odor compounds such as nitrogen oxides, methyl compounds and sulfide did not increase. On the 9th day of storage, the thiobarbituric acid reactive substances (TBARs) value of all samples with fat replacement was significantly lower than that of the control group (P < 0.05). Therefore, whey protein isolate pre-emulsions containing 72% soybean oil was the best fat replacer, and the best replacement level was 25%.

In order to reduce the content of saturated fat in emulsified sausage, the effects of using flaxseed gum-linseed oil (FG-LO) emulsion to replace pork backfat at different proportions (25%, 50%, 75% and 100%) on the color, cooking loss, emulsion stability, texture, moisture distribution, lipid oxidation, microstructure and sensory quality of emulsified sausage were investigated. The emulsified sausage without fat replacement was used as control. The brightness (L* value) increased significantly (P < 0.05), and the redness (a* value) decreased significantly (P < 0.05) in the fat replacement groups when compared with the control group; however, the yellowness (b* value) did not significantly change (P > 0.05), and there was no obvious difference in the color observed by the naked eye. The lowest cooking loss and water loss were observed at replacement proportions of 100% and 75%, respectively, while the fat loss had no significant changes at different replacement proportions (P > 0.05). As the replacement level of fat increased, the hardness decreased gradually and the texture became soft, indicating that fat replacement improved the texture of emulsified sausage. After adding FG-LO emulsion, emulsified sausage exhibited the conversion of free water to immobilized water, indicating that FG could interact with meat proteins to form a three-dimensional network structure to lock water molecules, thus enhancing the water-holding capacity. The extent of lipid oxidation was enhanced by the addition of FG-LO emulsion. The results of scanning electron microscopy (SEM) showed that the microstructure of the emulsified sausage with a replacement level of 25% was the most uniform and exquisite, with smaller pores. The sensory evaluation results showed that only the 100% replacement group was significantly different from the control group in terms of texture and overall acceptability (P < 0.05). The results of principal component analysis (PCA) showed that the emulsified sausage with 25% fat replacement was the most similar to the control group. Collectively, 75% fat replacement could reduce the cooking loss, increase the water-holding capacity (WHC), and result in the best emulsion stability and softer texture without causing any significant difference in the sensory quality of emulsified sausage.