<i>Eucalyptus globulus</i> Essential Oil as a Natural Food Preservative: Antioxidant, Antibacterial and Antifungal Properties <i>In Vitro</i> and in a Real Food Matrix (Orangina Fruit Juice)

• Main Authors: Mohamed Nadjib Boukhatem, Asma Boumaiza, Hanady G. Nada, Mehdi Rajabi, Shaker A. Mousa
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Applied Sciences
• Subjects: natural food preservative; <i>Eucalyptus globulus</i> essential oil; eucalyptol; antioxidant effect; vapor phase; Orangina fruit juice
• Online Access: https://www.mdpi.com/2076-3417/10/16/5581

The potential application of <i>Eucalyptus globulus</i> essential oil (EGEO) as a natural beverage preservative is described in this research. The chemical composition of EGEO was determined using gas chromatography analyses and revealed that the major constituent is 1,8-cineole (94.03% ± 0.23%). The <i>in vitro</i> antioxidant property of EGEO was assessed using different tests. Percentage inhibitions of EGEO were dose-dependent. In addition, EGEO had a better metal ion chelating effect with an IC₅₀ value of 8.43 ± 0.03 mg/mL, compared to ascorbic acid (140.99 ± 3.13 mg/mL). The <i>in vitro</i> antimicrobial effect of EGEO was assessed against 17 food spoilage microorganisms. The diameter of the inhibitory zone (DIZ) ranged from 15 to 85 mm for Gram-positive bacteria and from 10 to 49 mm for yeast strains. <i>Candida albicans</i>, <i>C.</i><i>parapsilosis</i> and <i>Saccharomyces cerevisiae</i> were the most sensitive fungal species to the EGEO vapor with DIZ varying from 59 to 85 mm. The anti-yeast effectiveness of EGEO alone and in association with heat processing was estimated in a real juice matrix (Orangina fruit juices) in a time-dependent manner. The combination of EGEO-heat treatment (70 °C for 2 min) at different concentrations (0.8 to 4 µL/mL) was effective at reducing <i>S. cerevisiae</i> growth in the fruit juice of Orangina, compared to juice preserved with synthetic preservatives. Current findings suggest EGEO as an effective and potent inhibitor of food spoilage fungi in a real Orangina juice, and might be a potential natural source of preservative for the food industry.