In this study we investigated the effect of droplet size on the antimicrobial activity of emulsions containing two essential oil compounds that are known for their antimicrobial effectiveness: carvacrol and eugenol. Coarse emulsions were prepared by blending a triacylglyceride (Miglyol 812N) containing various concentrations of carvacrol or eugenol (5, 15, 30, 50 wt%) at an oil droplet mass fraction of 10 wt% with an aqueous phase containing 2 wt% Tween 80^®. Premixes were then further dispersed using a high shear blender, a high pressure homogenizer at different pressures or an ultrasonicator to produce droplets with a variety of mean diameters. Microscopy and light scattering storage stability studies over 10 days indicated that manufactured emulsions were stable, i.e. that no aggregation, creaming or other destabilization mechanisms occurred and droplet size distributions remained unchanged. The antimicrobial activity of emulsions was assessed against two model microorganisms, the Gram negative Escherichia coli C 600 and the Gram positive Listeria innocua, by determining growth over time behavior. The analysis yielded the unexpected result that emulsions with larger droplet sizes were more effective at inhibiting growth and inactivating cells than smaller ones. For example, emulsions with a mean oil droplet size of 3000 nm at a concentration of 800 ppm carvacrol completely inhibited L. innocua, while for 80 nm emulsions, only a delay of growth could be observed. Measurements of the concentration of the antimicrobial compounds in the aqueous phase indicated that concentrations of eugenol and carvacrol decreased with decreasing oil droplet sizes. Determination of interfacial tension further showed that eugenol and carvacrol are preferentially located in the oil–water interfaces. Theoretical calculations of Tween 80^® concentrations needed to saturate interfaces suggested that in small emulsions for the given formulation less Tween 80^® micelles are present in the aqueous phase. We therefore attribute the fact that antimicrobial nanoemulsions are less active than macroemulsions due to an increased sequestering of antimicrobials in emulsion interfaces and a decreased solubilization in excess Tween 80^® micelles.

Animal fat tissue (that is, pork or beef fat) is composed of liquid and solid fat incorporated in a network of connective tissue. Hence, their rheological and thermal properties may differ significantly from plant‐derived fats. Specifically, animal fats have elastic and melting properties that give rise to not only a certain comminution behavior during processing, but also provide meat products such as sausages with certain organoleptic properties. To mimic key properties of animal fat tissue with plant‐derived materials, a new structuring approach was used. Canola oil was mixed with <30% (w/w) of fully hydrogenated canola oil at 65 °C, hot‐emulsified with a soy protein suspension (8%, w/w) at a lipid content of 70% (w/w) using a high‐shear disperser, and cooled to 37 °C. The concentrated, emulsified fat crystal networks were then incubated with transglutaminase for 1 hr to induce protein crosslinking. Microscopy images showed that samples were composed of tightly packed lipid particles with regions of coalesced or unemulsified lipids appearing at higher solid fat concentrations. Texture analysis and rheological measurements showed that crosslinked samples possessed elasticities that decreased with increasing solid fat concentration. Above 30% solid fat, matrices reverted back to exhibiting a mainly plastic behavior. Results were attributed to the formation of either a droplet‐filled protein network, a particulate fat crystal network, or a mixture thereof. Taken together, results show that plant‐based crosslinked emulsified fat crystal networks are able to mimic mechanical properties of animal fat provided that not too much solid fat (<30% in this study) is used. This makes them useful for the manufacture of meat products or analogues. Practical Application: This study introduced a new structuring approach to mimic properties of animal fat tissue with only plant‐derived materials. The structured lipids can, for example, be used for the manufacture of processed meat analogues.

Meat color research from the last two decades suggests that a combination of different intrinsic (ultimate pH, age of the animals, muscle position, breed, slaughter weight, and sex) and extrinsic factors (production systems and feeding, pre-mortem stress, slaughter season, and chilling rates) might have a deep impact in the color of beef muscle and influence consumers’ acceptance of fresh meat. Ultimate pH and muscle position were perceived as the most determinant intrinsic factors, whereas production systems, feeding, and ante-mortem stress were the extrinsic factors that more strongly influenced beef color attributes. From an industrial perspective, the extrinsic factors can be improved through the technological process at a higher ratio than the intrinsic ones. This review aims to evaluate the effect of each of those factors on myoglobin oxidation and beef color traits from a comprehensive standpoint. All the information discussed in this manuscript focuses on an industrial environment and offers possible solutions and recommendations for the global meat industry.