**4. Antimicrobial activity of EOs**

The antimicrobial effect of essential oils is attributed to actions including alteration of the permeability, and disruption of lipophilic cell membrane. The antimicrobial potential of essential oils can be completely associated with their constituents. Phenolic compounds with their hydrophobicity inherent, breakdown the lipid of cell membrane and mitochondria and enhance the permeability [31, 32]. The inherent of cellular energy generation system (ATP) and damage of proton motive force is a result of changing cell and cytoplasmic membrane permeability [33]. In addition, leakage of internal contents of the cell during the disruption of the membrane is another mechanism which causes cell death [32]. It is generally believed that Gram-negative bacteria are more resistance to essential oils because of their outer hydrophilic cell wall which exhibits inhibitory activity against the penetration of phenolic components [34].

Algae extracts and their components have displayed antimicrobial activity against organisms found in foods. Algae extracts and their components have displayed antimicrobial activity against organisms found in foods. The antibacterial activities of essential oils from two red seaweed *Laurencia obtuse* and *L. obtusa* var. *Pyramidata* showed that the essential oils from Laurencia obtuse exhibited the strong antimicrobial effect against Gram-positive (*Bacillus subtilis*, *Staphylococcus aureus*, methicillin-oxacillin resistant *Staphylococcus aureus*, *Enterococcus faecalis* and *Staphylococcus epidermidis*), Gram-negative bacteria (*Enterobacter cloaceae*) and yeast (*Candida albicans*) [16].

**197**

life of chilled stored fish [37].

*Application of Essential Oils for Shelf-Life Extension of Seafood Products*

Terpenoids, thymol, carvacrol, β-cubebene, β-eudesmol, β-ionone, dactylol and pachydictol A are the usual volatile compounds in seaweeds and it is known that there is correlation between β-ionone and antibacterial and antifungal activity of seaweeds [17]. However, two known sesquiterpenes (1R\*,2S\*,3R\*,5S\*,8S\*,9R\*)- 2,3,5,9-tetramethyltricyclo(6.3.0.01,5)undecan-2-ol and (1S\*,2S\*,3S\*,5S\*,8S\*,9S\*)- 2,3,5,9-tetramethyltricyclo-(6.3.0.01,5)undecan-2-ol were isolated from the red macroalgae *Laurencia dendroidea* had no antibacterial effect on eight bacteria strains (*Staphylococcus aureus*, *Bacillus subtilis*, *Enterococcus faecalis*, *Streptococcus* 

The short shelf-life of fresh seafood is a practical issue in the industries and distribution chain systems. Short shelf-life caused by chemical and microbial spoilage reactions can be stopped by traditional preservation methods but there is increasing interest in natural preservation methods. EOs are natural antioxidants and antimicrobials by which the shelf-life of seafood can be extended alone or in combination with other techniques. However, the reduction of antimicrobial effect of EOs in a food system due to some components of food and also the reverse action of EOs as antioxidant agents in some cases, has slowed down the use of them in

Combination of EOs exhibit the synergistic antimicrobial activity. Thus, using of EOs into packaging can be the safe approach for food preservation technology [35]. The antimicrobial activity of gelatin-chitosan films incorporated with organo essential oil exhibited the great inhibitory effect through reducing the *E. coli*, *S. aureus*, *B. subtilis* and *B. entritidis* growth. Its inhibition zone was larger for Grampositive bacteria compared with Gram-negative bacteria. Furthermore, the lower total aerobic plate count and total volatile basic nitrogen values that can extend the shelf life of grass carp muscle was recorded in fish muscle packed with film containing the 4% organo essential oil. It seems the high percentage of carvacrol, eugenol, and thymol as phenolic components are responsible for this antimicrobial activity by damaging the cell membrane or interfere the enzyme functionality located on the cell wall. Moreover, the TVB-N value of sample packaged with gelatinchitosan-EOs film was lower compared with control and the shelf life of grass carp muscle packaged with the film containing EOs was extended to 12 days [36]. The same observation was gained from the gelatin-chitosan film incorporated with other EOs including clove, fennel, cypress, lavender, thyme, herb-of-cross, pine and rosemary for cod fillet preservation. Among all EOs, the high antimicrobial effect was obtained from clove against a wide range of food pathogen and spoilage bacteria such as *Salmonella*, *Lactobacillus*, *Listeria*, *Citrobacter*, *Escherichia*, *Yersinia*, *Brochothrix*, *Staphylococcus*, *Bacillus*, *Listeria*, *Clostridium*, *Aeromonas*, *Shewanella*, *Vibrio* and *Photobacterium*. In addition, the film containing the clove essential oil used for preservation of cod fillets, lowered the microorganisms in particular, *Entrobacteria*. Further, by delaying the formation of TVB-N, can extend the shelf

Immersion of salmon in marinade solution containing 1 w/w% essential oil from organo, cinnamon and thyme revealed that the antimicrobial effect, however, organo and cinnamon essential oil caused to enhance the shelf life of salmon and scampi. In addition, reduction of yeast and mold was observed by cinnamon (1%) addition in marinade for 6 days. Moreover, salmon treated with marinade containing 1% essential oil, shoed appropriate sensorial properties and high hedonic score

*pneumonia*, *Klebsiella pneumoniae*, *Salmonella typhi*, *Escherichia coli* and

*Pseudomonas aeruginosa*) and the yeast *Candida albicans* [5].

**5. Shelf-life extension of seafood products**

practical systems.

*DOI: http://dx.doi.org/10.5772/intechopen.86574*

*Application of Essential Oils for Shelf-Life Extension of Seafood Products DOI: http://dx.doi.org/10.5772/intechopen.86574*

*Essential Oils - Oils of Nature*

activities, respectively [30].

**Figure 3.**

*et al. [42]).*

**4. Antimicrobial activity of EOs**

penetration of phenolic components [34].

yeast (*Candida albicans*) [16].

The lipid oxidation is one of the most important limiting factors for the shelflife seafood products. For this purpose the antioxidant activity of the EOs of five Mediterranean spices (*Origanum vulgare*, *Thymus vulgaris*, *Rosmarinus officinalis*, *Salvia officinalis*, and *Syzygium aromaticum*) was analyzed. The *S. aromaticum* essential oil, which comprised the highest level of total phenols (898.89 mg/l GAE), demonstrated the highest antioxidant activity (98.74% for DPPH radical inhibition and 1.47 TEAC for FRAP value). The EOs extracted from *T. vulgaris* and *R. officinalis* showed the highest TBARS inhibition (89.84%) and iron (II) chelating (76.06%)

*The effect of pectin-CEO coating on the bream fillets at day 1 and day 15 of the storage (adopted from Nisar* 

The antimicrobial effect of essential oils is attributed to actions including alteration of the permeability, and disruption of lipophilic cell membrane. The antimicrobial potential of essential oils can be completely associated with their constituents. Phenolic compounds with their hydrophobicity inherent, breakdown the lipid of cell membrane and mitochondria and enhance the permeability [31, 32]. The inherent of cellular energy generation system (ATP) and damage of proton motive force is a result of changing cell and cytoplasmic membrane permeability [33]. In addition, leakage of internal contents of the cell during the disruption of the membrane is another mechanism which causes cell death [32]. It is generally believed that Gram-negative bacteria are more resistance to essential oils because of their outer hydrophilic cell wall which exhibits inhibitory activity against the

Algae extracts and their components have displayed antimicrobial activity against organisms found in foods. Algae extracts and their components have displayed antimicrobial activity against organisms found in foods. The antibacterial activities of essential oils from two red seaweed *Laurencia obtuse* and *L. obtusa* var. *Pyramidata* showed that the essential oils from Laurencia obtuse exhibited the strong antimicrobial effect against Gram-positive (*Bacillus subtilis*, *Staphylococcus aureus*, methicillin-oxacillin resistant *Staphylococcus aureus*, *Enterococcus faecalis* and *Staphylococcus epidermidis*), Gram-negative bacteria (*Enterobacter cloaceae*) and

**196**

Terpenoids, thymol, carvacrol, β-cubebene, β-eudesmol, β-ionone, dactylol and pachydictol A are the usual volatile compounds in seaweeds and it is known that there is correlation between β-ionone and antibacterial and antifungal activity of seaweeds [17]. However, two known sesquiterpenes (1R\*,2S\*,3R\*,5S\*,8S\*,9R\*)- 2,3,5,9-tetramethyltricyclo(6.3.0.01,5)undecan-2-ol and (1S\*,2S\*,3S\*,5S\*,8S\*,9S\*)- 2,3,5,9-tetramethyltricyclo-(6.3.0.01,5)undecan-2-ol were isolated from the red macroalgae *Laurencia dendroidea* had no antibacterial effect on eight bacteria strains (*Staphylococcus aureus*, *Bacillus subtilis*, *Enterococcus faecalis*, *Streptococcus pneumonia*, *Klebsiella pneumoniae*, *Salmonella typhi*, *Escherichia coli* and *Pseudomonas aeruginosa*) and the yeast *Candida albicans* [5].
