• Korean Journal of Medicinal Crop Science
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• v.22 no.3
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• pp.203-209
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• 2014

Onion (Allium cepa L.) is one of the richest sources of flavonoids in human diet. Onion peel contains over 20 times more quercetin than onion flesh. In this study, we studied the effects of onion peel water extract (OPE) on the blood lipid profiles in mice. The onion peel extracts was extracted with hot water. The experimental groups were divided with 3 groups (n = 6) of ICR male mice: normal diet + distilled water (NC), high-fat diet + distilled water (HF), high-fat diet + onion peel water extract 20 mg/kg (OPE-20). The oral administration was conducted daily. The experimental period was 7 weeks. Onion peel water extract showed higher concentration of polyphenol gallic acid and anti-oxidant trolox equivalent than the ethanol extract. The body weight gain and food efficiency ratio was significantly lower in the OPE-20 group as compared with HF group (p < 0.05). The epididymal fat and retroperitoneal fat showed significantly lower weights and sizes in the OPE-20 group as compared with HF group (p < 0.05). The serum levels of total cholesterol, LDL cholesterol and triglyceride were significantly lower in the OPE-20 group as compared with HF group (p < 0.05). The OPE-20 group showed higher HDL cholesterol concentration than HF group (p < 0.05). Atherogenic index was ignificantly lower in as compared with HF group (p < 0.05). The serum levels of glucose, GOT and GPT were significantly lower in the OPE-20 group as compared with HF group (p < 0.05). In these results, we suggests that onion peel water extracts supplementation can reduces the serum lipid components and improves the lipid metabolism in hyperlipidemic mice induced with a high-fat diet.

• Food Science and Preservation
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• v.8 no.2
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• pp.131-139
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• 2001

Kiyomi tangor(Citus unshiu x sinensis) was stored at 3$\^{C}$ and 85% relative humidity, and the changes in firmness, pectin degrading enzymes activity and other physicochemical properties of citrus fruits during storage were investigated. Decay ratio and weight loss during 180 days’ storage were increased gradually to 13.0% and 12.9%, respectively. Firmness of fruits with 2 mm probe was decreased gradually from 808.7 g-force to 406.4 g-force, and moisture of peel and flesh were decreased from 76.5% to from 89.6% to 87.6% during storage, respectively. Exo-polygalacturonase activity of peel after 150 days’ storage were increased gradually to 558.09 units/100g. Pectin methylesterase activity of peel and flesh were increased from 14.7 units/g to 2.3 units/g, and from 9.4 units/ml to 2.7 units/ml at 150days’ storage, respectively. Endo-polygalacturonase activities were not changed notably during storage. Alcohol-insoluble solid(AIS) of peel was not changed notably. During storage of the fruits water soluble pectin(WSP) of peel and flesh were increased from 474.49 mg/100g to 614.29mg/100g, and from 66.91mg/100g to 92.74mg/100g as wet basis, respectively. Hexameta-phosphate soluble pectin(HMP) of peel were decreased from 405.5mg/100g to 270.43mg/100g, hydochloric acid soluble pectin(HSP) of peel was also decreased from 544.02mg/100g to 412.64mg/100g during storage. Total pectin substance(TPS) of peel and flesh were decreased from 1,424.01mg/100g to 1,297.36mg/100g, and from 165.51mg/100g to 171.54mg/100g, respectively. Composition ratio of pectin was in order of WSP > HSP > HMP.

• Journal of the Korean Society of Food Culture
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• v.20 no.6
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• pp.721-730
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• 2005

Recently, epidemiological evidence has raised concerns that moderate elevation in body iron stores may increase oxidative stress and the risk of cardiovascular disease and cancer. Onion flesh or peel contains antioxidant such as flavonoids and alk(en)ylcysteine sulphoxides. This study was conducted to examine the effect of onion flesh or peel feeding on antioxidative capacity in aged rats supplemented with high dietary iron. Thirty-two Sprague-Dawley male 16-month-old rats weighing $618{\pm}6g$ were acclimated for 10 days with medium-iron diet (35ppm in diet), and blocked into 4 groups according to their body weights and raised for 3 months on either control diets (adequate iron-35ppm or high iron-350ppm) or experimental diets containing onion flesh/peel (5% w/w in diet) with high iron (350ppm). Rats fed high iron-onion peel diet had significantly high quercetin and isorhamnetin levels in plasma whereas rats fed high iron-onion flesh diet did not show. Plasma TBARS level was lowered by onion flesh or peel diet with high iron supplementation. However, there was no significant difference in cellular DNA damage in brain and kidney tissue among all experimental groups. We concluded that high iron diet (10 times higher than requirement) tend to increase oxidative stress and it is plausible that onion flesh or peel feeding enhances antioxidative capacity in the elderly even with iron supplementation.

• Korean journal of food and cookery science
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• v.21 no.3 s.87
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• pp.354-359
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• 2005

To investigate the physiological activities and development of tangerine peel tea, we examined the antioxidant effect of tangerine peel tea and determined the physicochernical characteristics including proximate composition, mineral contents, color values and sensory evaluation. The wet weight composition of tangerine peel tea was $61.6\pm0.3mg$ of crude carbohydrate, $15.0\pm20mg$ of crude lipid, $8.3\pm2.1mg$ of crude Protein and $7.6\pm0.1mg$ of crude ash. The pH of tnagerine peel tea decreased with increasing preparation temperature. The Hunter color values (L and a values) generally increased with increasing preparation temperature. Total phenolic contents of tangerine peel tea were $16.0 mg\%\;at\;60^{\circ}\;18.9mg\%\;at\;80^{\circ}C\;and\;20.9m\%\;at\;100^{\circ}C$. As the preparation temperature of tangerine peel tea increased, the radical scavenging activity (DPPH) also increased obviously. In the sensory evaluation, the tangerine peel tea prepared with 1 g at $80^{\circ}C$ obtained the best result with high scores in overall acceptability.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.5
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• pp.388-396
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• 2002

Quality characteristics of Yukwa, Korean traditional rice cookie, added with citrus peel (2, 4 and 6%) were investigated. Yukwa was prepared by adding the water homogenate of the peel and the quality characteristics were evaluated by the expansion rate, texture, color, sensory quality and content of total carotenoid, hesperidine and naringin. The expansion rate (1,517~855%) of Yukwa with higher concentrations of citrus peel powder was lower than that of control product (1,740%) and the brittleness followed the same trend. However, the values were in the range of those of the traditional Korean Yukwa. The color of the control Yukwa (L* value: 63.3~49.9, a* value: 10.6~17.8, b* value: 12.6~56.4) was white, but with citrus peel (2~6%) light yellow~yellow (L* value. 63.3~49.9. a* value: 10.6~17.8, b* values: 12.6~56.4). Carotenoid, hesperidin and naringin contents of Yukwa with the addition of peel powder were 0.18~0.51 mg%, 36.55~101.60 mg% and 24.65~70.81 mg%, respectively. The color and the overall acceptability of yukwa with 4% of citrus peel powder were the best. This combination had some orange flavor, but no differences in both sweet and sour taste.

• Rapid Communication in Photoscience
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• v.2 no.1
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• pp.28-30
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• 2013

The extract of Punica granatum peel was separated and confirmed by HPLC, and punicalagin, one of the extract, was better antibacterial activity against Salmonella.

• Journal of the Korean institute of surface engineering
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• v.29 no.4
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• pp.238-252
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• 1996

In order to study the effect of interface oxides on the adhesion strength of the copper/epoxy system, copper foils were immersed in black oxide or brown oxide forming solutions before lamination with epoxy prepregs, and variation of peel strength with the treatment time were investigated. Results showed that peel strength decreased rapidly up to 1 minute of treatment lime and remained constant in the case of the black oxide treated specimens, which was accompanied by the thickening of $Cu_2O$ at the Copper/Epoxy interface during the period. In contrast, peel strength increased rapidly up to 1 minute of treatment time and remained constant in the case of the brown oxide treated specimens, which could be ascribed to the thickening of CuO. Subsequent heat treatments of the Copper/Epoxy laminations at $120^{\circ}C$ in air showed that peel strength remained constant in the case of the black oxide treated specimens but decreased gradually in the case of the brown oxide treated specimens. Following XPS analyses revealed that the latter was possibly caused by the coalescence of CuO at the Copper/Epoxy interface into $Cu_2O$.

• Korean Journal of Medicinal Crop Science
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• v.21 no.4
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• pp.255-261
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• 2013

The purpose of this study was to examined the antioxidant activities by water and 70% ethanol extract from durian (Durio zibethinus.) seed, sarcocarp and peel. Durian extract were studied for reducing sugar content, polyphenol content, superoxide dismutase (SOD) like activity, electron donating ability, nitrite scavenging ability, flavonoid content, hydroxy radical scavenging activity. Reducing sugar content were increased peel > sarcocarp > seed. Total polyphenol, flavonoid content, DPPH radical scavenging ability and SOD like activity were increased seed > peel > sarcocarp. Total polyphenol content was relatively high as $21.90{\pm}0.50mg/g$ in the ethanol extract of the seed. DPPH radical scavenging ability was relatively high as $62.08{\pm}2.63%$ in the water extract of the seed. Nitrite scavenging ability was no significant difference. Hydroxy radical scavenging activity was increased seed > peel > sarcocarp, was relatively high as $58.27{\pm}1.13%$ in the water extract of the seed.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.13-17
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• 1993

When mandarin orange peel was used for a substrate of citric aCid fermentation by Aspergillus niger, principal enzyme activities were investigated. Not only the activity of polygalacturonase and pectin esterase being capable of digesting pectin and crude fiber of mandarin orange peel. but also that of carboxymethyl cellulase, xylanase and amylase was high. In carbohydrate metabolism, the activity of enzymes related in HMP pathway was higher than that in EMP pathway at the orange peel medium designed hereby rather than synthetic medium. Productivity of citric acid was significantly increased when the activity of citrate synthetase was high and 5imultaneously those of aconitase and NADP-dependent dehydrogenase were low.

• Food Science and Preservation
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• v.1 no.1
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• pp.9-14
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• 1994

Soluble solids($^{\circ}$Brix), acid content and edible part ratio of Citrus unshiu collected at sorting Places in south Cheju area wee more lowered, and peel thickness was more thickened with increasing fruit size. Compared to early variety of Citurs unshiu(C. unshiu Miyakawa Mar), peel thickness of medium variety of Citurs unshiu(C. unshiu Hayashi Mar) was more thickened, and edible part ratio was more lowered with increasing fruit size. Soluble solids of medium variety of Citurs unshiu were lowered, and acid contents were increased compared to early variety. Processing properties for pressing concentrated juice was good for early variety of Citurs unshiu, especially on fruit diameter of 50-65mm. Soluble solids, acid contents and juice ratio were decreased with increasing peel thickness. The quality properties for fresh fruit with peel thickness had a good correlation on early variety of Citurs unshiu, and these data are supposed to be applied to the quality evaluation of Citurs unshiu produced in Cheju.