• Food Science and Preservation
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• v.10 no.3
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• pp.288-292
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• 2003

Grapefruit seed extract powder (GFSEP), which was made with grapefruit seed extract and calcium carbonate, was investigated to retard the fermentation rate. The mixing ratios of GFSEP to salted Chinese cabbage were 0.1, 0.3 and 0.5％. Quality characteristics of kimchi such as pH, titratable acidity, reducing sugar content and microbial loads were measured during fermentation at 10$^{\circ}C$. pH and reducing sugar content of control and kimchi sample with 0.1％ GFSEP showed decreases until 10 days, and then attained to stabilized levels. Kimchi samples with 0.3％ and 0.5％ GFSEP maintained a higher pH and reducing sugar content, while microbial load was lower than others. Based on the pH and tit ratable acidity, kimchi samples with GFSEP prolong the shelf life about 3～10 days.

• Korean Journal of Plant Resources
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• v.32 no.3
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• pp.207-219
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• 2019

Ultraviolet (UV) radiation is associated with the development of extrinsic skin aging. We performed in vivo assays in order to investigate the protective effect of a combination of grapefruit and rosemary extracts (cG&Re) on UVB-induced skin aging. The results indicated that cG&Re displayed elastase inhibitory activity in a dose-dependent manner. Topical application of cG&Re mitigated photo-aging related lesions such as skin erythema and thickening in photo-aged BALB/c mice dorsal skin, by preventing UVB-induced collagen degradation. Immunohistochemical analyses revealed that cG&Re stimulated SIRT-1 expression, and suppressed MMP-1 and $IL-1{\beta}$ expression. It was observed that expression of MMP-1 and -13 mRNA was downregulated in the cG&Re-treated group. Furthermore, cG&Re treatment drastically suppressed protein expression of MMP-1 and regulated the phosphorylation of p-38 kinase. As expected, oral administration of cG&Re resulted in the same SIRT-1, MMP-1, and $IL-1{\beta}$ expression patterns observed upon topical application of cG&Re in the UV-induced mice model. Overall, the current results demonstrated that cG&Re attenuated both the downregulation of MMP-1 expression and up-regulation of SIRT-1 expression, as well as decreased phosphorylation of MAPK in UVB-induced skin ageing mice model, suggesting that cG&Re might be used as an internal food ingredient for beauty-purposes as well as a functional food material.

• 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.

• 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.

• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.485-497
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• 2003

Grapefruit seed extract has been reported to have antimicrobial effect. The purpose of this study was to evaluate the antimicrobial and anti-gingivitis effect of chewing gum containing grapefruit seed extract and xylitol. 40 healthy subjects with gingivitis or early periodontitis were divided into two groups. Subjects in the experimental group chewed gum containing grapefruit seed extract and xylitol while subjects in the control group chewed gum containing only xylitol. All subjects received scaling and tooth brushing instruction. 1 week after scaling was set as baseline. Gingival index and plaque index were scored at baseline, 1 week, 2 week, 3 week and 4 week. Bleeding index, probing pocket depth and clinical attachment level were scored at baseline, 2 week and 4 week. The number of total bacteria and Streptococcus mutans in unstimulated saliva of experimental group were counted at 1 week, 2 week, 3 week and 4 week. Gingival indices of experimental group and control group at baseline, 1 week, 2 week, 3 week and 4 week were 0.850${\pm}$0.298, 0.575${\pm}$0.345, 0.533${\pm}$0.332, 0.459${\pm}$0.311, 0.408${\pm}$0.224 and 0.758${\pm}$0.379, 0.592${\pm}$0.276, 0.563${\pm}$0.281, 0.454${\pm}$0.194, 0.413${\pm}$0.199 (mean${\pm}$SD), respectively. Plaque indices of experimental group and control group at baseline, 1 week. 2 week, 3 week and 4 week were 0.497${\pm}$0.500, 0.375${\pm}$0.484, 0.332${\pm}$0.471, 0,286${\pm}$0.452, 0.210${\pm}$0.407 and 0.411${\pm}$0.492, 0.375${\pm}$0.484, 0.354${\pm}$0.479, 0.313${\pm}$0.463, 0.193${\pm}$0.395, respectively. Bleeding indices of experimental group and control group at baseline, 2 week and 4 week were 0.377${\pm}$0.177, 0.298${\pm}$0.152, 0.192${\pm}$0.108 and 0.383${\pm}$0.124, 0.318${\pm}$0.153, 0.225${\pm}$0.126, respectively. Probing pocket depth of experimental group and control group at baseline, 2 week and 4 week were 2.56${\pm}$1.00, 2.40${\pm}$0.65, 2.23${\pm}$0.64 and 2.45${\pm}$0.682.37${\pm}$0.57, 2.19${\pm}$0.57, respectively. Clinical attachment level of experimental group and control group at baseline, 2 week and 4 week were 2.58${\pm}$1.01, 2.43${\pm}$0.67, 2.26${\pm}$0.65 and 2.49${\pm}$0.70, 2.40${\pm}$0.59, 2.22${\pm}$0.62, respectively. The % of reduction of total bacteria in saliva of experimental group at 2 week, 3 week and 4 week were 46 ${\pm}$ 53%, 53 ${\pm}$ 5% and 69 ${\pm}$ 33%. The % of reduction of Streptococcus mutans count in saliva of experimental group at 2 week, 3 week and 4 week were 52${\pm}$69%, 88${\pm}$30% and 89${\pm}$17%. From these findings, it can be concluded that regular use of grapefruit seed extract /xylitol chewing gum may be effective to control and prevent gingivitis and may have caries-preventive effect.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.255-258
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• 2018

The objective of this study was to investigate the inhibitory effect of natural antimicrobials on Listeria monocytogenes isolated from Korean slaughterhouses. A mixture of 15 strains of L. monocytogenes at low (3 Log CFU/mL) or high (7 Log CFU/mL) concentration was exposed to various extracts (grapefruit seed extract, citrus fruit extract, ginger extract, pear extract, Japanese apricot concentrate, balloon flower extract, jujube extract, and omija extract) at $0.001-4.0{\mu}g/mL$. Ginger extract, pear extract, Japanese apricot concentrate, balloon flower extract, jujube extract, or omija extract showed no antimicrobial effects on high-concentration of L. monocytogenes (7 Log CFU/mL). However, grapefruit seed extract and citrus fruit extract showed antibacterial effects against L. monocytogenes at 3 and 7 Log CFU/mL with MBCs of 0.001 and $0.002{\mu}g/mL$, respectively. These results indicate that grapefruit seed extract and citrus fruits extract can be used to control L. monocytogenes as natural antimicrobials.

• 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.

• Food Science and Preservation
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• v.11 no.3
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• pp.411-416
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• 2004

Botanical antimicrobial agent-grapefruit seed extract mixture(BAAG), which could be applied to the preparation of antimicrobial packaging paper, was investigated in order to prove the preservative function of fruits and vegetables. HAAG showed remarkable antimicrobial effects against Fusarium solani Botrytis cinerea, Pencillium crustosum, Erwinia carotovora, Phoma destructiva and Alternaria radicina causing the postharvest decay of fruits and vegetables. We have examined that HAAG could inhibit the growth of microorganims when treated with more than 500 $\mu$g/mL concentration. The activities of HAAG were stable in the wide spectrum of pH and temperature. Direct visualization of microbial cells by using scanning electron microscope showed the loss of microbial cell membrane function, which was destroyed by treating with the dilute solutions of HAAG. We could confirm that HAAG be an antimicrobial agent for the preparation of antimicrobial packaging paper.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.265-270
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• 1993

In order to retain the freshness of fruits and vegetables and to reduce the rate of disease damage, grafruit seed extract (GPSE), natural microorganism control agent, was applied during the preservation process of fresh fruits and vegetables. GFSE showed an effective inhibitory action against plant putrefactive bacteria and fungi which were involved in the decay of fruits and vegetables. Minimal inhibitory concentrations for GFSE against the microbes were in the range of 50 to 2,000 ppm. Direct observation of microbial cells and spores using electron microscopy showed their function was destroyed by the treatment of the dilute solutions of GFSE. Fresh Welsh onions, onions and red peppers treated with GFSE and stored in polyethylene film (0.1 mm) retained better quality in color and texture than the non-treated control. GFSE was efficient in controlling the germination of potatoes. It was observed that GFSE would reduce disease damages and have bactericidal and fungicidal properties during the storage of such fruits and vegetables as zucchinis, cucumbers, tomatoes and mandarin oranges.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.291-298
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• 2017

We compared the ingredients present in freeze-dried ground food samples with those present in hot air-dried and ambient ground food samples to optimize processing conditions for preserving nutrients in and for improving the ingestion of different foods. The freeze-dried ground sample of black bean showed 4.57% higher retention rate than the ambient ground sample of black bean. Mineral content was also significantly different between these two samples. Moreover, the freeze-dried ground sample of black bean contained 11.54% higher content of ${\beta}$-carotene, a precursor of vitamin A, than the ambient ground sample of black bean. Total anthocyanin content was 453.49 mg in the freeze-dried ground sample of Aronia compared with 158.98 mg in the ambient ground sample of Aronia. Contents of ${\beta}$-carotene and niacin increased by 129.47% and 439.39%, respectively, in the freeze-dried ground sample of grapefruit. Retention rates of proteins, carbohydrates, and niacin were 107.74%, 103.87%, and 156.52%, respectively, in the freeze-dried ground sample of germinated brown rice. Protein digestibility increased by 120.5% and 101.14% in the freeze-dried ground samples of Aronia and black bean, respectively, but did not increase in the freeze-dried ground samples of grapefruit and germinated brown rice.