Essential Oils from Citrus Fruit Peels to Control Foodborne Bacteria in Fresh-cut Guava Fruits

Abstract

Peels from Citrus sinensis and C. limon were used for the preparation of essential oils. The hydrodistilled citrus peels presented various compounds, including cyclohexene, 1-methyl-4-(1-methylethenyl)-, (S)- (91.8%) and 7-methyl-3-methylene-1,6-octadiene(3.40%). Compared with the essential oils isolated from C. limon, the C. sinensis essential oil showed maximum radical scavenging activity, with an IC₅₀ value of 4.31 µg/mL. Bacillus subtilis growth was generally inhibited by essential oils, and the zone of inhibition was 21 ± 1 mm, while the zone of inhibition was 20 ± 2 mm against Escherichia coli. The minimum inhibitory concentration ranged from 12 ± 1 to 128 ± 2.6 µg/mL. Similarly, essential oils presented lower minimum bactericidal concentrations against Bacillus subtilis, followed by Escherichia coli. The antimicrobial activity was tested using packed samples of fresh-cut guava fruit stored under refrigeration. The essential oil-treated guava fruit presented a decreased viable cell count. After 2 days of C. sinensis and C. limon essential oil treatment, the reduction in B. subtilis was approximately 1.7 log CFU/g compared with that of the control. In cut fruits treated with L. monocytogenes, the essential oils significantly reduced the bacterial population, and a 7 log CFU/g reduction was achieved after 8 days of treatment (p<0.05).