• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1169-1176
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• 2007

Genes encoding proteins responsible for limonene catabolism were cloned from a limonene-degrading microorganism, Enterobacter cowanii 6L, which was isolated from citron (Citrus junos) peel. The 8.6, 4.7, and 7.7 kb fragments (CD3, CD4, and CD6) of E. cowanii 6L chromosomal DNA that confer to E. coli the ability to grow on limonene have been cloned and their corresponding DNA sequences were determined. Nine open reading frames (ORFs) were identified, and the four ORFs (921 bp of CD3-2; 1,515 bp of CD4-1; 1,776 bp of CD6-1; and 1,356 bp of CD6-2) that encode limonene hydroxylase were confirmed by independently expressing these genes in E. coli. FAD and NADH were found to stimulate the hydroxylation reaction if added to cell extracts from E. coli recombinants, and multiple compounds (linalool, dihydrolinalool, perillyl alcohol, (${\alpha}-terpineol$, and ${\gamma}-terpineol$) were the principal products observed. Our results suggest that the isolate E. cowanii 6L has a broad metabolic capability including utilization of limonene. This broad metabolic ability was confirmed by identifying four novel limonene hydroxylase functional ORFs in E. cowanii 6L.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1463-1471
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• 2015

The surface modified activated carbons (SMACs) were prepared with various $P_2O_5$ concentrations using two activated carbons (ACs: waste citrus peel-based activated carbon and coconut-based activated carbon). The characteristics and adsorptivity of bisphenol A (one of phenolic endocrine disrupting chemicals) were compared between ACs and SMACs. The contents of C, H and N of SMACs were similar to those of ACs, but the content of $P_2O_5$ for the former increased greatly than for the latter, due to the impregnation of $P_2O_5$ into the pores. The specific surface area, total pore volume, average pore diameter and iodine adsorptivity for the former decreased due to the impregnation of $P_2O_5$ into the pores, compared to those for the latter. The adsorptivity of bisphenol A for the former were higher than that for the latter, although specific surface area, total pore volume, average pore diameter and iodine adsorptivity for the former were lower than those for the latter.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.151-160
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• 1998

Tangerine peel is mostly discarded as waste in citrus processing. However, tangerine peel contains besides dietary fibers bioflavonoids such as naringin and hesperidin which act as antimicrobials and blood pressure depressants, respectively. A continuous membrane separation process was optimized for the production of bioflavonoids relative to feed flow rate, transmembrane pressure, temperature, and pH. The tangerine peel was blended with 7.5 times water volume and the extract was prefiltered through a prefiltration system. The prefiltered extract was ultrafiltered in a hollow fiber membrane system. The flux and feed flow rate didn't show any apparent correlation, but we could observe a mass-transfer controlled region of over 8 psi. When temperature increased from $9^{\circ}C\;to\;25^{\circ}C$, the flux increased about $10\;liters/m^2/min\;(LMH)$ but between $25^{\circ}C\;and\;33^{\circ}C$, the flux increased only 2 LMH. At every transmembrane pressure, the flux of pH 4.8 was the most highest and the flux at pH 3.0 was lower than that of pH 6.0, 7.0, or 9.0. Therefore, the optimum operating conditions were 49.3 L/hr. 10 psi, $25^{\circ}C$, and pH 4.8. Under the optimum conditions, the flux gradually decreased and finally reached a steady-state after 1 hr 50 min. The amount of dietary fibers in 1.0 g retentate in each separation step was analyzed and bioflavonoids concentration in each permeate was measured. The contents of total dietary fiber in the 170 mesh retentate and soluble dietary fiber in the prefiltered retentate were the highest. Naringin and hesperidin concentration in the permeate were $0.45{\sim}0.65\;mg/g\;and\;5.15{\sim}6.86\;mg/g$ respectively, being $15{\sim}22$ times and $79{\sim}93$ times higher than those in the tangerine peel. Therefore, it can be said that PM 10 hollow fiber membrane separation system may be a very effective method for the recovery of bioflavonoids from tangerine peel.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.496-502
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• 2005

The chemical properties and nitrite scavenging ability were analyzed which on a citron (Citrus junos) of 4 kinds purchased in different regions [Namhae (I, II), Tongyoung and Koheung] in Korea. Four kinds of organic acids were determined. Citric acid contents in flesh and peel of citron were $10.2\pm0.14\~17.7\pm0.17\;g/100g$. The organic acid content was the highest in citron purchased from Koheung. Total mineral content in citron was in a range of $2,844.3\~4,022.4$ mg/100 g, the potassium content was the highest in the range of $1,332.4\pm2.31\~2,308.5{\pm}3.25\;mg/l00g$. The major free amino acid from citron were proline, asparagine and glutamic acid. And the highest in peel of citron purchased from Tongyoung by 326.9 mg/100 g. However, the kinds and contents of chemical components in citron were somewhat different among various regions. The electron donating ability using DPPH method of citron juice was more than $80.0\%$ at the concentration of $0.1\~0.2\%$ and it was stronger by increased the juice concentration in the reaction mixture. SOD-like activity showed $10.2\pm0.50\~20.1\pm0.77\%$ at the concentration of $0.01\~0.2\%$. The nitrite scavenging ability was pH and sample concentration dependent. It was the highest at the pH 1.2 and more than $73\%$ in $0.1\~0.2\%$ citron juice. On the contrary in all concentration of added citron juice lower than $27\%$ at pH 4.2.

• Korean journal of food and cookery science
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• v.26 no.1
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• pp.79-87
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• 2010

The antioxidant activity of hot water extracts made from Yuza (Citrus junos SIEB ex TANAKA) cultivated in Namhae Changseon, Seolcheon and Idong-myeon was analyzed. The total phenolic compound content was significantly higher in the Seolcheon sample (116.06 mg/100 g) than in Idong or Changseon. Flavonoids and hesperidin contents were not significantly different among samples. The electron-donating ability of the Yuza peel hot water extracts was activated to over 55% in all samples with $5,000\;{\mu}g/mL$ added to the reaction system, with especially high in the Seolcheon sample (85.70%). Also, the reducing powder in $10,000\;{\mu}g/mL$ added to the reaction system was showed significantly higher in the Seolcheon (0.82) than in the other samples. The ABT cation decolorization capacity of Yuza peel extracts was activated to over 50% in all samples when $5,000\;{\mu}g/mL$ of water extracts were added to the reaction mixture, and the activity was the highest (67.59%) in the Idong samples. The nitric oxide scavenging activity was lower than 45% in all samples, with the activity of Changseon significantely lower than the other samples. The antioxidant activity of the $\beta$-carotene linoleic acid system was 33.30~42.22% when $1,000\;{\mu}g/mL$ water extracts was added to the reaction mixtures, of which the activity in the Yuza cultivated in Seolcheon showed the highest.

• Korean journal of food and cookery science
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• v.26 no.1
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• pp.18-25
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• 2010

This study was carried out to investigate the total polyphenol and flavonoid contents and antioxidative activities of enzymatic digests from dried Citrus unshiu and C. grandis peels. The yields of digests from dried C. unshiu and C. grandis peels were high in viscozyme (a carbohydrase) and kojizyme (a protease), and enzymatic digests from dried C. grandis peels appeared highly comparable to those of C. unshiu. Total polyphenol contents were high in ultaflo (a carbohydrase) and alcalase and flavourzyme (proteases), and the digests from dried C. unshiu peels appeared high in comparison to C. grandis. Total flavonoid contents were high in ultaflo, alcalase, and water extract. DPPH radical scavenging activities appeared very high in digests from dried C. grandis peels in comparison to C. unshiu, and was the highest in viscozyme and kojizyme. The viscozyme digest displayed particularly high activity. Hydrogen peroxide scavenging activities increased somewhat with increasing amounts of digests, but displayed very high activity, more than 91%, except kojizyme the digest from dried C. unshiu peel, at 2.0 mg/mL. Alkyl radical scavenging activities increased rapidly with increasing amounts of digest, and all enzyme digests from dried C. unshiu and C. grandis peels displayed very high activities at more than 0.5 mg/mL. Hydroxyl radical scavenging activities increased rapidly with increasing amounts of digests, and all enzymatic digests from dried C. unshiu and C. grandis peels displayed relatively low activities in comparison to other activated oxygen species.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1239-1245
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• 2005

Hallabong peel oils grown in open field and green house were extracted by hand-pressing flavedo and collected on ice. Volatile flavor components of Hallabong peel oils were identified and compared by using gas chromatography and mass- spectrometry. Forty-four flavor components were identified in open field oil and 45 flavor components in green house oil. (E) -Limonene-1,2-epoxide and neral were identified only in Hallabong oil grown in open field, on the other hand, $\beta$-cubebene, $\beta$-elemene and decyl acetate were detected only in green house oil. Limonene was the most abundant component in both oils as more than 86$\%$ of peak weight, followed by sabinene (1.8$\~$ 3.6$\%$) and myrcene (2.4$\~ $2.6$\%$). The difference of the volatile profile between open field and green house oils were significantly characterized by identification and quantity of alcohol group. The total alcohols in open field and green house oils accounted for 1.8$\%$ and 0.8$\%$, respectively. Among alcohols, the level of linalool was relatively high in open field oil (1.2$\%$), however, it accounted for 0.5$\%$ in green house oil. Flavor properties of fresh Hallabong peel and flesh were also examined by sensory evaluation. Flavor properties of fresh Hallabong grown in open field were relatively stronger on both peel and flesh by sensory analysis. Sweetness was strong in Hallabong flesh from open field, and sourness in that from green house. The sensory evaluation of the preference in consideration of taste and aroma was significantly high in Hallabong grown in open field (p<0.01). From the present study, the stronger flayer properties and the preference of Hallabong from open field by sensory evaluation seem to be associated with the high level of linalool in its peel oil, and the composition of monoterpene hydrocarbons such as sabinene and (E) -$\beta$ -ocimene.

• Korean Journal of Food Science and Technology
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• v.43 no.5
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• pp.577-582
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• 2011

Greenhouse satsuma mandarins (Citrus unshiu Marc., cv. Gungchun) of an early harvesting cultivar were treated by hot water showering at 65$^{\circ}C$ for 10 s at a commercial scale in a packing house and then stored at 5$^{\circ}C$ for 3 weeks and subsequently at 18$^{\circ}C$ for 1 week (simulated shelf-life) to examine the potential use of hot water treatment (HWT) as an environmentally benign method to maintain mandarin quality characteristics during postharvest storage and sale. The respiration rate just after heat treatment or during storage was at a similar level in both the treated and untreated fruit. HWT also had no detrimental effects on quality attributes including pH, titratable acidity, soluble solids content, weight loss, firmness, and peel color. The development of stem-end rot, mold decay, and black rot was lower in the heat-treated fruit compared to those in the untreated control. A sensory evaluation showed that HWT markedly improved fruit appearance, making the fruit cleaner and glossier. The results suggested that HWT can be applied to satsuma mandarin as an effective pretreatment to maintain postharvest quality during storage and marketing.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.143-147
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• 2013

'Sangdojosaeng' is a new cultivar from bud spot of Citrus unshiu 'Sasaki unshiu' which has late maturity habit. It was found in 1996, and primary selected and named as 'JARES108' in 1998. 'JARES108' was grafted on to adult satsuma mandarin trees in Seogwipo-si and Jeju-si in 2000. Four years survey on the characteristics of trees and fruits from 2003 to 2006 was carried and confirmed the superiority. Thus it was finally selected as 'Sangdojosaeng'. 'Sangdojosaeng' is a very early wase type satsuma mandarin. It shows relatively strong tree vigor among the very early wase type varieties and its branches are spreading. Its ripening time is late October, 25 days earlier than 'Sasaki unshiu'. Compared to 'Ueno wase' which has similar characteristics with 'Sangdojosaeng' such as ripening time, tree vigor, fruit type and peel color, its soluble solid content of fruit is $0.6^{\circ}Bx$ higher and acidity was a little lower than 'Ueno wase'. Because this cultivar has good quality and its tree makes vigorous growth among very early wase type varieties in Jeju, we expect to substitute it for some very early wase type varieties such as 'Miyamoto wase', 'Ichifumi wase', 'Yamakawa wase', etc.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.540-544
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• 2012

The aim of this study was to evaluate the antioxidant activity, total phenolics, flavonoids, and vitamin C contents in peels of 11 commercial fruits commonly consumed in the Republic of Korea. The antioxidant activities were evaluated by ABTS, DPPH radical scavenging methods and reducing power. The peels of plum (Prunus spp.) and golden kiwifruit (Actinidia chinensis) exhibited the highest values of antioxidant activity and total phenolics, while the highest level of ascorbic acid was recorded in the peel of citrus fruit (p<0.05). There were positive correlations between the antioxidant activity assessed by both reducing power and ABTS methods and total polyphenol content ($R^2$=0.6356), suggesting that phenolic compounds are the major contributors to these activities. The results indicate that plum and golden kiwifruit peels can be used as natural antioxidant ingredients and in production of functional foods in the Korean diet.