Nanoemulsions: Synthesis, Characterization, and Application in Bio‐Based Active Food Packaging

Abstract

The increasing demands for foods with fresh‐like characteristics, lower synthetic additive and preservative contents, and low environmental footprint, but still safe to consume, have guided researchers and industries toward the development of milder processing technologies and more eco‐friendly packaging solutions. As sustainability acquires an increasingly critical relevance in food packaging, bio‐based and/or biodegradable materials stand out as suitable alternatives to their synthetic counterparts. In this context, the use of nanoemulsions has represented a step forward for improving the performance of sustainable food packaging devices, especially for the successful incorporation of new compounds and functionalities into conventional films and coatings. This class of emulsions, featuring unique optical stability and rheological properties, has been developed to protect, encapsulate, and deliver hydrophobic bioactive and functional compounds, including natural preservatives (such as essential oils from plants), nutraceuticals, vitamins, colors, and flavors. This article presents the surfactants (including naturally occurring proteins and carbohydrates), dispersants, and oil‐soluble functional compounds used for designing food‐grade nanoemulsions intended for packaging applications. The improved kinetic stability, bioavailability, and optical transparency of nanoemulsions over conventional emulsions are discussed considering theoretical concepts and real experiments. Bottom‐up and top‐down approaches of nanoemulsion fabrication are described, including high‐energy (such as high‐pressure homogenizers, microfluidics, ultrasound, and high‐speed devices) and low‐energy methods (for instance, phase inversion and spontaneous emulsification). Finally, incorporation of nanoemulsions in biopolymer matrixes intended for food packaging applications is also addressed, considering current characterization techniques as well as their potential antimicrobial activity against foodborne pathogens.

Improving storage quality of refrigerated steamed buns by mung bean starch composite coating enriched with nano‐emulsified essential oils

“…This type of antimicrobial coating is widely applied in fresh‐cut fruits and vegetables, meat (chicken, pork, and shrimp, etc. ), cheese and bakery foods (Espitia, Fuenmayor, & Otoni, 2019). There are several reports available related to edible coating in steamed pastry, for example, Eom, Chang, Lee, Choi, and Han (2018) coated the steamed rice cake with the mixture of waxy corn starch and edible gums to retard starch retrogradation, but no work report applying the coating enriched with nano‐emulsified essential oil to delay the microbial spoilage and extend the shelf life of steamed buns.…”

Encapsulation Systems for Antimicrobial Food Packaging Components: An Update

“…Lipophilic compounds can be encapsulated in oil-in-water (O/W) emulsions, while hydrophilic compounds can be encapsulated in water-in-oil (W/O) or oil-in-water emulsions. Multiple emulsions such as water-in-oil-in-water (W/O/W) and oil-in-water-in-oil (O/W/O) can also be used to encapsulate active compounds in order to improve delivery requirements [125,126]. emulsion droplets takes place by adsorption of small solid particles at the surface of the emulsion droplets, although the mechanism of adsorption is very different to the one of surfactants [153].…”

Food-Grade Nanoemulsions: Preparation, Stability and Application in Encapsulation of Bioactive Compounds

“…SE, also named as emulsification by solvent diffusion (ESD), can take place through numerous mechanisms [10] and provides the potential for an affordable approach. The spontaneous formation of an O/W nanoemulsion facilitated by specific temperatures relies on the chemical compounds present in both phases, as well as the utilized emulsifier [34].…”

“…High-energy methods usually consume significant energy (~10 8 –10 10 W/kg) to form small droplets. Furthermore, in the utilization of high-energy methods, the oil and water phases are breached and blended using the powerful cavitational, shear and turbulent flow profiles created by the specifically designed devices [9,10].…”