• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.277-283
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• 1994

An antimicrobial chitinase was purified from grapefruit extract and its properties were characterized. The chitinase was purified with a single step chromatography on regenerated chitin affinity gel column. The molecular weight of the purified chitinase was 29 kDa. The grapefruit extract contained the chitinase protein more than 50% of its total soluble proteins measured by coomassie stained protein bands. When the purified chitinase was incubated with polymers of N-acetylglucosamine (NAG), such as mycelia of Fusarium oxysproum and swollen chitin, they were degraded to oligosaccharides, and the oligosaccharides were then further hydrolyzed by the same enzyme to monomer and dimer of NAG. This result suggests that the chitinase contained both endo- and exo- chitinase activities. The chitinase was stable to heat and pH treatment; its activity was not diminished by the heat treatment upto 7$0^{\circ}C$ for 1 hr, and it showed a pH stability in the range of pH 4.0 to 12.0.

• Food Science and Preservation
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• v.13 no.2
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• pp.168-173
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• 2006

To investigate the effect of grapefruit seed extract pretreatment and packaging materials on the quality of dried persimmon, dried persimmons were stored for $60{\sim}100$ days at room temperature $(15^{\circ}C)$ after dipping in grapefruit seed extract and then packing with LDPE (low density polyethylene) film and Nylon/LDPE film pouch $(30{\times}30cm^2)$. Weight loss of dried persimmon packaged with Nylon/LDPE film was not exceeded 86% of control. 60% mold occurrence and 50% browness were observed compared to control. There were no significant differences in the firmness, soluble solid content and color between grapefruit seed extract pretreatment and control. Grapefruit seed extracts pretreatment had an effect on the inhibition of color change in Hunters value.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.6
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• pp.948-956
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• 2013

This study investigated methods to improve the quality of Topokkidduk using grapefruit seed extracts and acid regulation agents. Topokkidduk was investigated in terms of its moisture, color, pH, texture, microbial composition, and sensory properties. The moisture content of Topokkidduk was highest for Topokkidduk supplemented with grapefruit seed extracts. The color of Topokkidduk (the L value) decreased, whereas the "a" value increased with the addition of grapefruit seed extracts. The texture of Topokkidduk was affected more by additives than storage temperature. The addition of grapefruit seed extracts and acid regulation agents were effective for the inhibition of microbial activity in Topokkidduk during storage. The overall acceptability values of Topokkidduk (without supplements) were highest among the samples. These results suggest that grapefruit seed extracts and acid regulation agents can be used to control microbial load and moisture levels in Topokkidduk.

• Journal of Food Hygiene and Safety
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• v.37 no.5
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• pp.356-363
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• 2022

To investigate the functional activity of different citrus fruit peels, antioxidant compounds in 70% ethanol extracts of mandarin, lemon, orange, and grapefruit peel powders were identified, and antioxidant and antibacterial activities were quantitated. Mandarin peel contained the highest content of total phenolic compounds and total flavonoid substances (21.46±0.12 mg GAE/g and 11.57±0.05 mg RE/g, respectively). The total phenolic compound content of the three other citrus fruits was 14.16±0.18-18.44±0.07, and their total flavonoid content was 5.51±0.10-7.46±0.09 mg RE/g. DPPH radical scavenging activity was the highest in lemon peel (87.64±0.21%), and mandarin peel displayed the best antioxidant activity with respective ABTS radical scavenging activity and FRAP measurements of 43.20±0.61% and 78.82±1.06 mM TE/g. Grapefruit peel antimicrobial activity increased with treatment time, and was the most potent among the four tested citrus species, inhibiting Staphylococcus aureus by about 4.05 log cycle. These findings demonstrate that mandarin and grapefruit peel can be used to prevent oxidation, improve food storage capabilities, and potentially preserve food quality.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.141-149
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• 1994

To investigate the distribution of Vibrio parahaemopyticus in the southern 4 coastal areas, Vibrio parahaemolyticus was isolated from seawater, shellfish and sediment from May to October in 1991, and antimicrobial effect of grapefruit seed extract (GFSE) on the growth of isolated strains were examined. In the 120 sample from 4 coastal areas, 16 strains of Vibrio parahaemolyticus were isolated and identified. The distribution serotype of isolated strains was 10 types of monovalent k-antiserum. Especially k-5 and k-28 were highly distribyted with 3 and 4 strains. 31.3% of isolated strains showed positive on Kanagawa phenomenon test. All isolated Vibrio parahaemolyticus were sensitive to chloramphenicol and gentamycin, 5 and 6 strains were resistant to streptomycin and colistin, respectively. Isolated strains were compared with geographical, month and sample. The distribution of 16 isolated Vibrio parahamolyticus was high at Hadong with 50%(8 strains), on July with 43.8%(7 strains) and from seawater with 37.5%(6 strains) respectively. Minimal inhibitory level of GFSE to Vibrio parahaemolyticus was 50 ppm. With 100 ppm treatment of GFSE, the destroy of cell membrane function, outflow of cell ingredients and ghost morphology of cell were investigated.

• Preventive Nutrition and Food Science
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• v.6 no.1
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• pp.1-5
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• 2001

Pigment extracts obtained from Star Ruby grapefruit pulp were stored at different temperatures (4.5$^{\circ}C$, 23$^{\circ}C$) and exposed to light. many carotenoid oxidation products were formed due to light-exposure during storage periods. They were monitored by using HPLC with photodiode array detection and tentatively identified. Including (all-E)-lycopene and trans-$\beta$-carotene as predominant carotenoids in red grapefruit, 5Z-lycopene, 9Z-lycopene, 13Z-lycopene, and 15-cis-$\beta$-carotene were formed at 4.5$^{\circ}C$, 23$^{\circ}C$. Degradation of all-tarns lycopene was more susceptible to light-exposure and temperature a than that of all-trans $\beta$-carotene. The formation of lycopene cis isomers was favored under lighted condition. Respectively, (5Z)-lycopene was formed in greater amounts than other isomers at 23$^{\circ}C$ storage. The concentration of 15-cis-$\beta$-carotene was significantly increased during storage at 23$^{\circ}C$ storage. The concentration of 15-cis-$\beta$-carotene was significantly increased during storage at 23$^{\circ}C$.

• Toxicological Research
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• v.17
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• pp.127-133
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• 2001

Together with cytochrome P450 (CYP), flavin-containing monooxygenase (FMO) present in liver microsomes oxidizes various endogenous and exogenous chemicals. In an effort to determine the human FMO activity, we have developed two non-invasive urine analysis methods using caffeine (CA) and ranitidine (RA) as the probe compounds. As the production of theobromine (TB) and ranitidine N-oxide (RANO) from CA and RA is catalyzed primarily by the hepatic FMO, we have assigned the urinary molar ratios of TB/CA and RA/RANO as the in vivo FMO activity. In 200 age-matched Korean volunteers, the obtained TB/CA ratio ranged from 0.4 to 15.2 (38-fold difference) and the RA/RANO ratio from 5.7 to 27.2 (4.8-fold). The FMO activity of 20's, determined by caffeine metabolism, was the highest (2.5$\pm$l.9) and those of 30's, 40's, 50's, 60's and 70's were 40%, 50%, 24%, 39% and 36% of the 20's, respectively. Intake of grapefruit juice, known to contain flavonoids, inhibited the in vivo FMO (TB/CA) activity by 79%. Addition of the flavonoids like naringin, quercitrin and kaempferol, present in grapefruit juice, to the in vitro microso-mal FMO assay, thiobenzamide S-oxidation, produced 75%, 70% and 60% inhibition, respectively. Obtained Ki values of quercitrin, kaempferol and naringin on the in vitro FMO activity were 6.2, 12.0 and 13.9 $\mu\textrm{M}$, respectively. This suggested that the dose of drug should need to be adjusted to suit the individual FMO activities when the drugs metabolized by FMO are given to patients. As the intake of grapefruit juice has been identified to inhibit the FMO as well as CYP3A4 and lA2 activities, patients taking drugs metabolized by these enzymes should not drink grapefruit juice as the carrier.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3559-3567
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• 2016

Background: In recent years, there has been considerable research on recycling of agro-industrial waste for production of bioactive compounds. The food processing industry produces large amounts of citrus peels that may be an inexpensive source of useful agents. Objective: The present work aimed to explore the phytochemical content, antioxidant, anticancer, antiproliferation, and antigenotxic activities of lemon, grapefruit, and mandarin peels. Materials and Methods: Peels were extracted using 98% ethanol and the three crude extracts were assessed for their total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant activity using DPPH (1, 1-diphenyl-2-picrylhydrazyl). Their cytotoxic and mitogenic proliferation activities were also studied in human leukemia HL-60 cells and mouse splenocytes by CCK-8 assay. In addition, genotoxic/antigenotoxic activity was explored in mouse splenocytes using chromosomal aberrations (CAs) assay. Results: Lemon peels had the highest of TPC followed by grapefruit and mandarin. In contrast, mandarin peels contained the highest of TFC followed by lemon and grapefruit peels. Among the extracts, lemon peel possessed the strongest antioxidant activity as indicated by the highest DPPH radical scavenging, the lowest effective concentration 50% ($EC_{50}=42.97{\mu}g\;extract/mL$), and the highest Trolox equivalent antioxidant capacity (TEAC=0.157). Mandarin peel exhibited moderate cytotoxic activity ($IC_{50}=77.8{\mu}g/mL$) against HL-60 cells, whereas grapefruit and lemon peels were ineffective anti-leukemia. Further, citrus peels possessed immunostimulation activity via augmentation of proliferation of mouse splenocytes (T-lymphocytes). Citrus extracts exerted non-cytotoxic, and antigenotoxic activities through remarkable reduction of CAs induced by cisplatin in mouse splenocytes for 24 h. Conclusions: The phytochemical constituents of the citrus peels may exert biological activities including anticancer, immunostimulation and antigenotoxic potential.

• Journal of Food Hygiene and Safety
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• v.6 no.1
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• pp.67-72
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• 1991

This study was carried out to investigate the preservative effect of grapefruit seed extract on fish meat product. he effect of GFSE has been tried on fish meat product divided into three lots; Control (no treatment), 500 ppm and 1,000 ppm of GFSE-treated samples. The results were summarized as follows; 1 During the storage of fish meat product, chagnges of crude protein contents of GFSEtreated samples were smaller than the control. 2 Texture was inclined to decrease as the storage period goes, the decrease ratio of GFSEtreated samples was smaller than the control. 3. SDS-PAGE patterns of fish meat product treated with or without GFSE showed that Mw 30,000-32,000 of major proteins were hydrolyzed and disappeared. The deterioration of fish meat product proteins occured in the storage period of 2 days in the control and 4-5 days in GFSE-treated samples. Conclusivery, the excellent preservative effects of GFSE on fish meat product were shown in the rheological, chemical test and sensory evaluation.

• 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.