Consumers today demand the use of natural additives and preservatives in all fresh and processed foods, including meat and meat products. Meat, however, is highly susceptible to oxidation and microbial growth that cause rapid spoilage. Essential oils are natural preservatives used in meat and meat products. While they provide antioxidant and antimicrobial properties, they also present certain disadvantages, as their intense flavor can affect the sensory properties of meat, they are subject to degradation under certain environmental conditions, and have low solubility in water. Different methods of incorporation have been tested to address these issues. Solutions suggested to date include nanotechnological processes in which essential oils are encapsulated into a lipid or biopolymer matrix that reduces the required dose and allows the formation of modified release systems. This review focuses on recent studies on applications of nano-encapsulated essential oils as sources of natural preservation systems that prevent meat spoilage. The studies are critically analyzed considering their effectiveness in the nanostructuring of essential oils and improvements in the quality of meat and meat products by focusing on the control of oxidation reactions and microbial growth to increase food safety and ensure innocuity.

Nanostructures are usually formed by solvent dissolution, but this paper proposes a green-chemistry method for thymol nano-encapsulation based on a chitosan–gelatin bio-copolymer matrix formation that enhances the physical stability to obtain a thymol-modified release system, with antioxidant capacity. Various ratios of chitosan–gelatin, gelatin types A and B, and crosslinkers were evaluated at a constant thymol concentration of 0.5 mg/ml. Gallic acid was chosen as the crosslinker. All batches were ultrasonicated to reduce particle size. The best conditions were obtained using a chitosan–gelatin ratio of 1:4 with type A gelatin, as those nanoparticles had higher physical stability, together with a smaller particle size (316.5 ± 2 nm) and higher thymol encapsulation efficiency (88 ± 3%). Antioxidant capacity was evaluated by DPPH, ABTS (radical inhibition 87.06 ± 4.38%, and 88.5 ± 4.42%, respectively), and a FRAP assay (1084.68 ± 54.32 µM Trolox equivalents). Release profiles were evaluated at two pH values (5.5, 7.0) and environmental temperatures (4, 25 °C). Diffusion was non-Fickian in all treatments. Gelatin type A systems exhibited a major physical stability, influencing the reduction of released thymol significantly. The research findings suggest that this submicronic dispersion can be used as a modified release system with high antioxidant activity and potentially serve as a preservative system during food storage.

Solid lipid nanoparticles (SLN) based on candelilla wax were prepared using the hot homogenization technique. The resulting suspension had monomodal behavior with a particle size of 809–885 nm; polydispersity index < 0.31, and zeta potential of −3.5 mV 5 weeks after monitoring. The films were prepared with SLN concentrations of 20 and 60 g/L, each with a plasticizer concentration of 10 and 30 g/L; the polysaccharide stabilizers used were either xanthan gum (XG) or carboxymethyl cellulose (CMC) at 3 g/L. The effects of temperature, film composition, and relative humidity on the microstructural, thermal, mechanical, and optical properties, as well as the water vapor barrier, were evaluated. Higher amounts of SLN and plasticizer gave the films greater strength and flexibility due to the influence of temperature and relative humidity. The water vapor permeability (WVP) was lower when 60 g/L of SLN was added to the films. The arrangement of the SLN in the polymeric networks showed changes in the distribution as a function of the concentrations of the SLN and plasticizer. The total color difference (ΔE) was greater when the content of the SLN was increased, with values of 3.34–7.93. Thermal analysis showed an increase in the melting temperature when a higher SLN content was used, whereas a higher plasticizer content reduced it. Edible films with the most appropriate physical properties for the packaging, shelf-life extension, and improved quality conservation of fresh foods were those made with 20 g/L of SLN, 30 g/L of glycerol, and 3 g/L of XG.

The objective of this study was to prepare zein–gum Arabic nanocapsules with rosehip oil (NC-RH), apply them to pork tenderloin, and analyze the changes in collagen structure under different conditions (pH 6.5 and 4.0) and temperatures (25 °C and 4 °C). NC-RHs were prepared using the nanoprecipitation method. Nanocapsules had a particle size of 423 ± 4.1 nm, a polydispersity index of 0.125 ± 3.1, a zeta potential value of −20.1 ± 0.41 mV, an encapsulation efficiency of 75.84 ± 3.1%, and backscattering (ΔBS = 10%); the antioxidant capacity of DPPH was 1052 ± 4.2 µM Eq Trolox and the radical scavenging capacity was 84 ± 0.4%. The dispersions exhibited Newtonian behavior at 25 °C and 4 °C. Incorporating NC-RH into acid marination benefited the tenderness, water-holding capacity, and collagen swelling, and favored changes in myofibrillar proteins corroborated with histological tests. The conditions with the best changes in pork tenderloin were a pH of 4.0 at 4 °C with an NC-RH-administered 11.47 ± 2.2% collagen area. Incorporating rosehip nanocapsules modifies collagen fibers and can be applied in pork marinades to increase the shelf life of a functional product.