ATR-FTIR, DSC, GC–MS of garlic (Allium sativum), parsley (Petroselinum crispum), and thyme (Thymus vulgaris) essential oils and their synergistic effects on antioxidant and antimicrobial properties

The study explored the chemical, antimicrobial, and antioxidant properties of essential oils from garlic (GEO), parsley (PEO), and thyme (TEO) using GC-MS, ATR-FTIR, and DSC techniques, and examined the synergistic effects of their combination on antioxidant and antimicrobial properties. The oils' antimicrobial effectiveness against pathogens was also tested. GC-MS analysis revealed diverse chemical profiles. The garlic, thyme, and parsley mixture (GTP) showed the highest phenol content (533.05 milligrams of gallic acid equivalent per 100 grams of dry weight sample), flavonoids (284.16 milligrams of quercetin equivalent per 100 grams of dry weight sample), and antioxidant activity (94.14% DPPH scavenging). The oils demonstrated significant antimicrobial effects, particularly against gram-negative bacteria and molds, with the GTP mixture being highly effective against Aspergillus niger . The bioactive compounds and antimicrobial effects were ranked as GTP > GT > GP > TP > GEO > TEO > PEO. These findings suggest that combining these EOs enhances their bioactivity, positioning them as natural preservatives for food safety and shelf-life extension. • GPT synergistic effects on antioxidants and antimicrobial properties were studied. • Garlic-thyme-parsley oil mixture showed the highest phenol and flavonoid content. • Essential oils displayed significant antimicrobial activity, especially against molds. • GC-MS analysis identified key bioactive compounds in garlic, parsley, thyme oils.