• Journal of Convergence for Information Technology
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• v.11 no.6
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• pp.198-205
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• 2021

Objectives: Antibiotics help treat Vaginitis, and prolonged usage of antibiotics can lead to resistance. Methods: This study investigates the antimicrobial activity of two types of lactic acid bacteria using essential oils. After cultivation by adding grapefruit seed extract (GSE), eucalyptus, tea tree, clove bud, cinnamon, lemongrass, thyme, and ginger oils in a specific ratio, pathogenic microorganisms, namely E. coli, C. albicans, and lactic acid bacteria were released. The number of bacteria was measured using a medium suitable for the strains. Results: The essential oils and GSE inhibited pathogenic microorganisms, and the inhibitory concentration of GSE against pathogenic bacteria (E. coli, C. albicans) was confirmed. The non-inhibitory mixing ratio was also confirmed (50 μl of eucalyptus globulus (EG) oil and 50 μl of melaleuca alternifolia oil (tea tree oil, TTO) at 200 ppm GSE (pH 5.0, 5.5, 6.0)). Conclusion: Essential oils can be considered as an alternative to antibiotics because of their antibacterial properties. They are useful as auxiliary antibacterial agents for patients under long-term antibiotic treatment.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.90-94
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• 2006

Bactericidal activity of grapefruit seed extract (GSE)-based disinfectant, as a safe disinfectant, was measured against five bacteria by Korean Food & Drug Administration (KFDA) dilution-neutralization method. GSE-based disinfectant showed a 99.9999% bactericidal activity against Escherichia coli ATCC 10536, Salmonella typhi ATCC 29629, Staphylococcus aureus ATCC 6538, Bacillus cereus ATCC 11778, and Listeria monocytogenes ATCC 1911 at the concentration of 2.15% GSE. It showed better bactericidal activity against Gram-negative bacteria of E. coli ATCC 10536 and S. typhi ATCC 29629 at lower concentration of GSE (0.43%). Based on the results, it was suggested that a possible bactericidal mechanism of GSE active ingredients was due to the abrupt osmotic shift during the bactericidal activity test by KFDA method.

• Food Science of Animal Resources
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• v.37 no.3
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• pp.429-439
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• 2017

This study investigated the antioxidative and functional effects of a curing agent containing grapefruit seed extract (GSE) on the quality and storage characteristics of chicken breast. The total polyphenol and total flavonoid contents of GSE were 45.06 mg/g and 36.06 mg/g, respectively. The $IC_{50}$ value of 2,2-diphenyl-1-picrylhydrazyl hydroxyl scavenging of GSE was $333.33{\mu}g/mL$. The chicken breast comprised six groups: no-treatment (N), 0.2% ascorbic acid + 70 ppm sodium nitrite (C), 0.05% GSE (G0.05), 0.1% GSE (G0.1), 0.3% GSE (G0.3), and 0.5% GSE (G0.5). The pH and cooking loss of cured chicken breast decreased with increasing GSE levels, and the water holding capacity increased with increasing GSE levels. The hardness and chewiness of GSE-treated chicken breast were higher than those of N and C. Hunter's L and a color values increased significantly after GSE addition. Moreover, 0.1% GSE (G0.1) increased the flavor and total acceptability scores. The 2-thiobarbituric acid and volatile basic nitrogen values of the 0.5% GSE group decreased significantly compared with those of C group. Total microbial counts of GSE-treated chicken breast were higher than those of C, but that lower than those of N. Adding GSE to chicken breast delayed lipid peroxidation and had antimicrobial effects during cold storage. GSE improved shelf life and palatability; therefore, it could be used as a natural antioxidant and functional curing agent ingredient in meat products.

• Food Science and Preservation
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• v.16 no.1
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• pp.134-137
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• 2009

The gelatin film containing grapefruit seed extract (GSE) was prepared by incorporating different amounts (0, 0.02, 0.05, 0.08, 0.1%) of GSE into the film. The tensile strength (TS) of the film increased by the addition of GSE, and water vapor permeability (WVP) of the film decreased. In particular, the gelatin film containing 0.1% GSE had a TS of 10.28 MPa, while the control had 8.68 MPa. WVP of the film containing 0.1% GSE decreased to 2.18 ng m/m2 s Pa, compared to 2.48 ng $m/m^{2}s$ Pa of the control. In addition, incorporation of 0.1% GSE to the gelatin film decreased the populations of Escherichia coli O157:H7 and Listeria monocytogenes by 2.67 and 3.15 log CFU/g, respectively, compared to the control. These results suggest that as a packaging material, gelatin film containing GSE can have antimicrobial activity against pathogenic microorganisms in foods.

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1177-1183
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• 2019

Grapefruit seed extract (GSE) is a safe and effective preservative that is used widely in the food industry. However, there are few studies addressing the anti-biofilm effect of GSE. In this study, the anti-biofilm effect of GSE was investigated against biofilm-forming strains of Staphylococcus aureus and Escherichia coli. The GSE minimum inhibitory concentration (MIC) for S. aureus and E. coli were $25{\mu}g/ml$ and $250{\mu}g/ml$, respectively. To investigate biofilm inhibition and degradation effect, crystal violet assay and stainless steel were used. Biofilm formation rates of four strains (S. aureus 7, S. aureus 8, E. coli ATCC 25922, and E. coli O157:H4 FRIK 125) were 55.8%, 70.2%, 55.4%, and 20.6% at $1/2{\times}MIC$ of GSE, respectively. The degradation effect of GSE on biofilms attached to stainless steel coupons was observed (${\geq}1$ log CFU/coupon) after exposure to concentrations above the MIC for all strains and $1/2{\times}MIC$ for S. aureus 7. In addition, the specific mechanisms of this anti-biofilm effect were investigated by evaluating hydrophobicity, auto-aggregation, exopolysaccharide (EPS) production rate, and motility. Significant changes in EPS production rate and motility were observed in both S. aureus and E. coli in the presence of GSE, while changes in hydrophobicity were observed only in E. coli. No relationship was seen between auto-aggregation and biofilm formation. Therefore, our results suggest that GSE might be used as an anti-biofilm agent that is effective against S. aureus and E. coli.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.239-246
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• 2016

This study was performed to investigate changes in characteristics of Umbilicaria esculenta Yakju added with 0.5% and 1% grapefruit seed extracts (GSE) during storage for 75 days at $25^{\circ}C$ and 165 days at $4^{\circ}C$. Quality characteristics of pH, titratable acidity, turbidity, total aerobic microbes, and ethanol, glucose, acetic acid, and lactic acid contents were analyzed. Control group showed sharply increased pH, titratable acidity, turbidity, and acetic acid and lactic acid has contents while the 0.5% and 1% GSE groups added to Yakju did not show significant changes in pattern (P<0.05). Total aerobic microbes increased rapidly during storage from 15 days in the control group, and the 0.5% and 1% GSE groups showed gradually increased total aerobic microbes from 30 days of storage compared to the control group (P<0.05). In addition, in all test groups, coli, yeast, and fungus were not detected. Ethanol content slightly increased during storage and glucose content slightly decreased, but there were no large changes during storage between the control group and GSE groups. Therefore, 3 months and $4^{\circ}C$ are considered safe for 6 months of storage, and GSE is effective to improve shelf-life and quality improvement of Yakju.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.370-374
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• 2008

The Gelidium corneum (GC)-whey protein isolate (WPI) blend film containing grapefruit seed extract (GSE) was prepared by incorporating different amounts (0, 0.02, 0.04, 0.08, 0.1%) of GSE into the film. The film's tensile strength (TS) and water vapor permeability (WVP) were improved by the addition of GSE. The film containing 0.1% GSE had a TS of 3.27 MPa, whereas the control had 2.64 MPa. WVP of the film was also significantly decreased by the addition of GSE. Addition of 0.1% GSE decreased the populations of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium by 1.0, 1.6, and 0.6 log CFU/g, respectively, compared to the control. Fish paste was packed with the GC-WPI blend film containing GSE, and microbial change in the fish paste inoculated with E. coli O157:H7, L. monocytogenes, and S. Typhimurium during storage was examined. Populations of E. coli O157:H7, L. monocytogenes, and S. Typhimurium were decreased by 0.60, 0.48, and 0.85 log CFU/g, after 7 day of storage, respectively. These results suggest packaging fish paste in the GC-WPI blend film containing GSE can extend the shelf life.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.246-253
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• 2003

Application of xylitol (Xyl) and grapefruit seed extract (GSE) to improve the quality and preservation of baechu kimchi was attempted. Xylitol and grapefruit seed extract at various combinatory concentrations were added into baechu kimchi and fermented for 25 days at $10^{\circ}C$. Assay was performed on sensory value, acidity, and bacterial growth. Addition of 0.1% GSE and 2% Xyl showed the highest score in the overall acceptability, sour taste, and texture. Score of intensity characteristics in smell and sour taste were the highest in the control and that of texture the highest in 0.1% GSE plus 2% Xyl treatment. The pH decreased, and titratable acidity, and growth of total viable cells and lactic acid bacteria were remarkably retarded in 0.1% GSE plus 2% Xyl group compared to the control. Results showed that application of 2% Xyl plus 0.1% GSE to the kimchi fermentation enhanced sensory value of the fermented product and extended the storage period by about twofold.

• The Korean Journal of Food And Nutrition
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• v.36 no.6
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• pp.515-525
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• 2023

This research aimed to examine the effects of grapefruit seed extract (GSE) at various concentrations on the microbial safety and physicochemical characteristics of onion puree (0.01~0.1%). The onion puree was kept at 4℃ for 14 days. The results of the study indicated that the addition of GSE did not cause any significant changes in the sample's brix degree and viscosity in onion puree (p<0.05). However, as the concentration of GSE increased, the pH level decreased. On the other hand, as GSE was added, the lightness of the onion puree increased, while the redness and yellowness decreased. Compared to pure onion puree, the GSE-incorporated onion puree had higher levels of total flavonoid and total polyphenol content, indicating that it helps to maintain antioxidant activities. Based on the microbial safety test, aerobic bacteria, yeast, and mold were absent until day 14 of storage. In conclusion, the study suggests that the addition of GSE to onion puree increases its antioxidant activity and shelf-life.

• Food Science and Preservation
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• v.17 no.2
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• pp.196-201
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• 2010

Gelatin films containing grapefruit seed extract (GSE) were prepared by incorporating different amounts (0, 0.6, and 1.0%, w/v) of GSE into film-forming solutions. Film elongation was improved by the addition of GSE, but film tensile strength decreased to 31.96 MPa for film containing 1.0% GSE, compared with 46.39 MPa for the control. Incorporation of 1.0% GSE inhibited the growth of pathogenic bacteria such as Escherichia coli O157:H7 and Listeria monocytogenes. Packaging of strawberries with a gelatin film containing 1.0% GSE decreased the levels of total aerobic bacteria and yeast/molds after 12 days of storage by 1.60 and 1.43 log CFU/g, respectively, compared with control values. Sensory evaluation results indicated that packaging of strawberries with GSE-gelatin film resulted in better sensory scores than those of the control. These results indicate that strawberries can be packaged using gelatin film containing GSE, to extend shelf-life.