*2.4.1 Application of essential oils by means of edible films to foods and their effect on sensory attributes*

The application of edible packaging as adjuvants for preservation (storage, quality, and safety) of foods, is one of the most effective solutions to ensure their safety [49].

Edible films can be applied as wrapping, packaging method, or layer spacing [8]. However, when the film directly covers the product, it can change its sensory characteristics. On the other hand, migration of the compounds present in the film can occur, similar to the phenomenon of mass transfer in vapor phase, resulting in the same alteration of aromas and flavors. Despite this, very few studies have carried out sensory analysis to evaluate the acceptability of different foods that have utilized edible films with EOs as a preservation method.

**Table 4** shows several studies where EOs have been applied to edible films and their effect on the sensory characteristics of selected meat and fish products. In general, EOs modified the studied sensory attributes. Sodium alginate EF with oregano (*O. vulgare*) and rosemary (*Salvia rosmarinus*) EOs have been evaluated in beef fillets [55] and with ginger (*Zingiber officinale*) and oregano EOs in tilapia fillets [56]. Results indicated that EFs with oregano EOs in these two products negatively affected sensory properties (aroma, taste, and overall acceptability) and judges preferred beef and tilapia fillets with rosemary and ginger EOs, respectively. Nonetheless, it has been reported that oregano EO applied in an EF of chitosan in red snapper, maintained good sensory attributes (aroma and taste) even after 20 d of storage [50].


*Methods of Application of Essential Oils in Foods and Their Effects on Sensory Attributes DOI: http://dx.doi.org/10.5772/intechopen.105162*


#### **Table 4.**

*Effect of selected essential oils applied by means of edible films (EFs) on the sensory attributes of various foods.*

A less common EO is zataria (*Zataria multiflora*), its main component is thymol (spice and wood flavor); it was incorporated into a starch EF and conferred good sensory properties on ground meat pies [58]. This same compound is present in thyme (*T. vulgaris*) EO, and it has been evaluated in products such as ground meat (color, aroma, and taste) [57], beef (appearance, color, aroma, taste, and overall acceptability) [52]**,** and sausages (aroma, color, taste, and overall acceptability [54]; all these authors highlight that the use of thyme EO generated good sensory attributes on their studied meat products.

## **2.5 Liposomes**

Liposomes are another encapsulation method and are defined as vesicles with a spherical structure, consisting of a phospholipid bilayer (or two or more of these bilayers, separated by liquid regions) that enclose aqueous or lipid soluble materials. The size of liposomes can vary from a few nanometers to 1 μm in diameter, and they are often used as delivery systems for a wide variety of bioactive compounds such as EOs [59].

The conventional manufacturing process of liposomes is based on the use of organic solvents to dissolve liposome building units, removal of the solvent to form the lipid bilayer, and the subsequent high-energy dispersion of the bilayer in water to form liposomes. However, its low load capacity, the high cost of materials and the need for complex preparation procedures limits its application in the case of largescale productions [60].
