• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.223-229
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• 1997

This study was undertaken in order to elucidate the elimination of fenitrothion residues during the dietary fiber and bioflavonoid preparations from mandarin orange peels. Dietary fibers were prepared from contaminated mandarin orange peels through homogenization, enzyme treatment, ethanol precipitation, acetone washing and air drying, at the yields of 17.4% total dietary fiber, 13.1% insoluble dietary fiber and 1.7% soluble dietary fiber. The removal rate of fenitrothion residues at 13 and 0.5 ppm levels in orange peels was 98.4% and 91.9% in total dietary fiber, 99.7% and 97.1% in insoluble dietary fiber, 100% and 99.6% in soluble dietary fiber, respectively. When bioflavonoid was prepared from contaminated mandarin orange peels through homogenization, soaking, ethanol precipitation, hexane and butanol extractions, the removal rate of fenitrothion residues was 92.7% in intermediate extract and 100% in final extract.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.39-46
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• 1997

Mandarin orange fruits were artificially contaminated with an organophosphorus insecticide phenthoate by dipping and the residue level of phenthoate was investigated during the purification steps of dietary fiber or bioflavonoid. The removal rate of phenthoate at 8 and 0.5 ppm levels was 98% in the total dietary fiber, 99% in the insoluble dietary fiber and 99.8% in the soluble dietary fiber preparations. Kuring the preparation of biflavonoid from peels at a 5 ppm pesticide level, the removal rate was 90% in the intermediate extract and 99.9% in the final extract. In conclusion, phenthoate residues in the peels of mandarin orange were mostly removed during the preparation processes of dietary fiber of bioflavonoid and its residue level would not raise any problem in safety aspects of the purified products.

• Journal of the Korean Wood Science and Technology
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• v.51 no.2
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• pp.98-108
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• 2023

In this study, the boards were manufactured according to the mandarin peels addition rate using sawdust and mandarin orange peel. After that, the mechanical properties and density profile of ceramics prepared by conditions through resin impregnation process and carbonization process were investigated. The bending and compression strengths of ceramics tended to increase as the resin impregnation rate increased. When the resin impregnation rate was 70%, the highest values were 8.58 MPa and 14.77 MPa, respectively. Also, the mechanical properties of ceramics according to carbonization temperature showed the highest values at 1,200℃ for bending strength of 11.09 MPa and compression strength of 17.20 MPa. The bending strength and compression strength according to the mandarin peels addition rate showed the highest values at 8.62 MPa and 14.16 MPa, respectively, when the mandarin orange peel addition rate was 5%. The mechanical properties tended to decrease when the addition rate of mandarin orange was increased. The density profile of ceramics showed a similar tendency to the mechanical properties. It can be seen that the density distribution from the surface layer to the center layer is more uniform as the resin impregnation rate and carbonization temperature increase and the mandarin peels addition rate decreases.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.510-518
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• 1989

Most of orange peels are disposed from orange juice manufacturing process. Thus, our purpose is to utilize these orange peels as fermentation substrate. We have investigated culture conditions and factors influencing citric acid production by an isolated strain, Asp. niger. Citric acid production was much higher in semisolid culture than in submerged culture and the particle size of ground orange peels was favored at 20 mesh in semisolid culture. The optimal pH and temperature were 4.5-5.0 and 3$0^{\circ}C$ respectively and the temperature cycling at 35$^{\circ}C$ for 20 hrs durig exponential phase, 1$0^{\circ}C$ for 4 hrs and 3$0^{\circ}C$ during stationary phase showed higher citric acid production than did at fixed temperature, 3$0^{\circ}C$. The addition of NH$_4$NO$_3$0.2%, MgSO$_4$7$H_2O$ 0.1%, methanol 2.5%, ethanol 1.5%, to culture medium promoted citric acid production but the addition of trace metal ions as nutrients had not effect on the acid production in orange peel medium. Under the optimal culture conditions, maximum yield of citric acid was 80.4% in solid medium. Almost of all original components of citrus peel was consumed by Asp. niger during fermentation.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.528-534
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• 2013

This study was carried out to explore a new application of board and obtain fundamental properties for producing composite board from sawdust and orange peels. As the mixing rate of orange peels increased from 10% to 40%, water absorption, thickness swelling, modulus of rupture and brinell hardness decreased as follows : 94.1%~86.5%, 27.2%~18.0%, $65.1kgf/cm^2{\sim}39.2kgf/cm^2$ and $195.3kgf/cm^2{\sim}180.3kgf/cm^2$, respectively. As the density of board increased from $0.4g/cm^3$ to $0.8g/cm^3$, thickness swelling, modulus of rupture and brinell hardness increased as follows: 6.4%~17.9%, $4.2kgf/cm^2{\sim}96.6kgf/cm^2$ and $40.4kgf/cm^2{\sim}196.2kgf/cm^2$, respectively. But the water absorption decreased from 149.2% to 58.6%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.143-149
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• 1994

Carotenoids isolated from orange peels were determined physicocohemical properties with TLC, UV-spectrophotometer and HPLC etc., and the results were as follows . Maximum absorption wavelength of the isolated carotenoids was 415nm when the result was similar to $\beta$-carotene as 423nm. Eight spots were obtianed from TLC, and identified lutein, lycopene, $\alpha$-carotene and $\beta$-carotene with HPLC. The effect pH during the storage period of isolate carotenoids, the period when the amount of pigment retention was over 50% in pH 5, 6 and 7 , after 10 days . The amount of pigment retention was lower in control than in treatment of sugars such as fructose, glucose and sorbitol , but sucrose was similar to the control, Isolated carotenoids were stable to ascorbic acid, and the amount of pigment retention was over 70% after 10 days. The amount of pigment retention in the effect oforganic acid was higher in treated citric acid , lactic acid and tartaric acid than in control, but lower in treated maleic acid and succinic acid. Isolated carotenoids were stable at 50 $^{\circ}C$, and the amount of pigment retention was over 50% at 10$0^{\circ}C$.

• Food Science and Preservation
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• v.30 no.2
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• pp.321-333
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• 2023

The study investigated the pH, acidity, soluble solids, total sugar, polyphenol, flavonoid, anthocyanin content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and color of kombucha with a variety of added fruit peels during the fermentation process. Pear, grape, plum, orange, apple, and golden kiwi peels were added during fermentation. The pH showed a decrease, while an increase in acidity was observed. An increase in soluble solids, which was higher in most experimental groups than the control group, was also observed. A decrease in total sugar was observed over time. However, an increase was observed in reducing sugar. On Day 0, higher total sugar and reducing sugar were detected in the peel addition group compared with the control group. The antioxidant capacity of polyphenol, flavonoid, anthocyanins, and DPPH radicals scavenging increased with fermentation and was higher in all addition groups, except for pear, compared with the control group. Except for grapes and plums containing high levels of anthocyanins, an increase in the L-value was observed over time, and an increase in the a-value of grapes and plums was also observed (p<0.05). The possible utilization of inedible fruit peel in kombucha was shown. Applying inedible fruit peels to kombucha is proposed to increase antioxidant content and modulate color and pH.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1237-1242
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• 2009

Polymethoxylated flavones (PMFs) extracted from Citrus sinensis 'Jincheng' peel were characterized by chromatographic and spectroscopic techniques. Seven individual PMF were identified. 3, 3', 4', 5, 6, 7-hexamethoxyflavone (HEX), nobiletin (NOB), heptamethoxyflavone (HEP), 5-demethylnobiletin (DN), and tangeretin (TAN) were characterized through electrospray ionization mass spectrometry (ESI-MS) in positive mode of protonated molecular ions $[M+H]^+$, the diagnostic fragment ions, together with the UV-Vis spectra and high performance liquid chromatography (HPLC) elution order from literature data. Sinensetin (SIN) and tetramethyl-O-scutellarein (SCU) were isolated and identified through their MS, $^1H$ nuclear magnetic resonance (NMR) and UV-Vis spectral studies. The levels of PMFs in peels from different cultivars of citrus fruits grown in China were determined for the first time. The results showed that C. aurantium 'Bitter orange' peel was the most promising variety for HEP. C. sinensis peel was a good source for SIN and SCU.

• 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 the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.247-254
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• 2016

This study evaluated the effects of low-dose X-ray irradiation treatment on quality characteristics and sensory evaluation of imported navel oranges during storage at $3^{\circ}C$ for 45 days. The samples were irradiated at doses of 0.2, 0.4, 0.6, 0.8, and 1.0 kGy, and changes in their color value, hardness, Brix/acid ratio, total sugar content, reducing sugar content, vitamin C contents, and sensory evaluation were investigated. There was no significant increase or decrease in Brix/acid ratio, total sugar content, reducing sugar content, or vitamin C content between the non-irradiated and irradiated samples. Color value of orange peels decreased with increasing levels of irradiation treatment. Color b value of orange pulp increased with an increase in irradiation dose. Difference in hardness between the non-irradiated and irradiated samples decreased at the end of storage. For the sensory evaluation after 30 days, sweetness and overall acceptability of irradiated samples at more than 0.6 kGy were low. These results suggest that X-ray irradiation under 0.6 kGy does not affect quality characteristics and sensory evaluation.