Impact of extraction techniques on phytochemical profile and antimicrobial activity of garlic essential oil

Fresh garlic and its essential oil serve as natural antioxidants, taste enhancers, and antimicrobials in the food industry. So, the aim of the work was to study the impact of different extraction methods of garlic essential oil (GEO) on phytochemical profile and antimicrobial activity. In this study 3 techniques for oil extraction such as conventional hydrodistillation (HD), supercritical fluid (SCF), and ultrasound-assisted (UAE) were used. The phytochemical, antioxidant activity, total phenolic, antimicrobial activity, and minimum inhibitory concentration (MIC) of GEO were evaluated. Fresh raw garlic pulp contains 65 % moisture, 27.5 % carbohydrate, 3 % protein, 2 % fiber, 2 ash and 0.5 fatty acids. Higher yield of oil extracted by SCF with ratio < 42% compared to HD and UAE. Total phenolic contents were 24.6%, 12.9%, and 5.3% for the SCF, HD, and ultrasound-assisted methods, respectively. A potential DPPH radical scavenging activity is showed in GEOs with IC50 values of 37.91, 218.7 and 262.54 µl/mL for SCF, HD, and UAE processes respectively. The results demonstrated that GEO obtained by HD was higher than those of SCF and UAE extracts was active against all tested strains i.e. Salmonella typhi, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, Staphylococcus aureus. Aspergillus niger, Aspergillus flavus, Candida albicans, and Saccharomyces cerevisiae. Results concluded that the GEO obtained using SCF demonstrated significantly (P ≤0.05) higher yield, higher quantities of bioactive compounds (TPC) and higher antioxidant. On the other hand, GEO made by SCF and UAE had lower antimicrobial and minimum inhibitory concentrations (MIC) than extracts made by HD.