• Korean Journal of Pharmacognosy
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• v.44 no.4
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• pp.391-396
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• 2013

In this study, we investigated the effects of onion(Allium cepa L.) peel extraction aplication on UVB-induced damage of mouse skin. The male C57BL/6 weeks mice were divided into three groups; the control group(Con), the UVB irradiated group(UVB) and the group treated with onion peel extract after UVB irradiation(UVB+Onion peel). Onion peel extraction were topically treated after UVB irradiation(800 $mJ/cm^2$) to dorsal skin. We were measured TEWL, melanin value, erythema index and histological of mouse skin. In the TEWL, melanin value and erythema index observation, UVB+onion peel group were decreased then in the UVB group and 120 and 168 hr groups were similar to the control group. In the histological observation, UVB+onion peel group were indicated hyperkeratosis then in the UVB. These results showed that onion peel extract as a topical application may have preventive effect against UVB-induced skin damage. Therefore onion peel extract might be good material for UVB-damage skin care.

• Journal of Nutrition and Health
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• v.37 no.8
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• pp.623-632
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• 2004

This study was performed to investigate effect of dried powder or ethanol extracts of onion flesh and peel intakes on lipid metabolism, antioxidative and antithrombogenic capacities in l6-month -old rats. Total of 40 Sprague-Dawley male rats of l6-month-old and weighing 816$\pm$6g were blocked into 5 groups according to body weight and raised for three months with control and experimental diets containing 5% (w/w) of dried powders of onion flesh or peel or ethanol extracts from equal amount of each dried powder. Contents of total flavonoids and total dietary fibers in peel powder were highest among onion preparations. Body weight gain and epididymal pad fat weight were lower in peel powder group than other groups. Plasma total lipid, triglyceride and total cholesterol concentrations of onion-containing groups were lower than control group. Above all, peel ethanol extract intake decreased them most remarkably. Plasma HDL-cholesterol concentrations in onion-containing groups were higher than control group, especially that of flesh powder group was the highest among groups. Liver total lipid, triglyceride and total cholesterol concentrations were not significantly different among all experimental groups. However, liver total lipid and triglyceride concentrations were tended to be lower in onion-containing groups than control group. Thiobarbituric acid reactive substances (TBARS) concentrations in LDL + VLDL fraction was not significantly affected by onion intakes, However peel powder group showed the lowest concentration, Plasma TX $B_2$ concentrations in onion flesh powder, peel powder and peel ethanol extract groups were lower than control group, while plasma 6-keto-PG $F_{1a}$ concentrations in these same groups were higher than control group. Clotting time was tended to be increased in peel ethanol extract group. In conclusion onion diets seemed to improve lipid metabolism and antithrombogenic capacity while effect on antioxidative was not significant.t.

• Nutrition Research and Practice
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• v.7 no.5
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• pp.373-379
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• 2013

The consumption of fruits and vegetables that have high polyphenol content has been previously associated with a reduced risk for cardiovascular disease. We investigated the effects of onion peel extract on plasma total antioxidant capacity, lipid peroxidation, and leukocyte DNA damage. This study was a randomized, double-blind, placebo-controlled, crossover trial. Healthy female subjects received either onion peel extract or placebo (dextrin) for two weeks, underwent a 1-week washout period, and then received the other treatment for an additional two weeks. After two weeks of onion peel extract supplementation, the total cholesterol level, low-density lipoprotein cholesterol level, and atherogenic index significantly decreased (P < 0.05). No changes were observed in activities of erythrocyte antioxidant enzymes or levels of lipid peroxidation markers following onion peel extract supplementation. Additionally, no significant difference was found in plasma antioxidant vitamin (retinol, tocopherols, carotenoids, and coenzyme Q10) levels or ex vivo $H_2O_2$-provoked oxidative DNA damage after onion peel extract supplementation. The present interventional study provides evidence of the health benefits of onion peel extract and demonstrates its effects in modulating lipid profiles in healthy young Korean women.

• 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 of Animal Resources
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• v.35 no.3
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• pp.277-285
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• 2015

This study was conducted to investigate the effects of kimchi powder and onion peel extract on the quality characteristics of emulsion sausage manufactured with irradiated pork. The emulsion sausages were formulated with 2% kimchi powder and/or 0.05% onion peel extract. The changes in pH value of all treatments were similar, depending on storage periods. The addition of kimchi powder increased the redness and yellowness of the emulsion sausage. The addition of onion peel extract decreased the thiobarbituric acid reactive substances value of the emulsion sausages prepared with irradiated pork. The volatile basic nitrogen value of the emulsion sausage prepared with kimchi powder was the highest, whereas that of the emulsion sausage prepared with onion peel extract was the lowest. The treatment without kimchi powder or onion peel extract and the treatments prepared with onion peel extract showed lower microbial populations than the other treatment. Sensory evaluations indicated that a higher acceptability was attained when kimchi powder was added to the emulsion sausages manufactured with irradiated pork. In conclusion, our results suggest that combined use of kimchi powder and onion peel extract could improve quality characteristics and shelf stability of the emulsion sausage formulated with irradiated pork during chilled storage.

• 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.

• The Korea Journal of Herbology
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• v.29 no.6
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• pp.141-148
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• 2014

Objectives : Onion (AlliumcepaL.) is one of the richest sources of flavonoids in human diet. In this study, we studied the effects of onion peel water extract (OPE) on the blood lipid profiles and glucose in rats. Methods : The experimental groups were divided with 5 groups (n = 6) of SD rats: normal diet + distilled water (NC), high-fat diet + Quercetin (PC), high-fat diet + onion peel water extract 4 mg/kg (OPE-4), high-fat diet + onion peel water extract 20 mg/kg (OPE-20), high-fat diet + onion peel water extract 100 mg/kg (OPE-100). Results : The liver fat showed significantly lower weights and size in the OPE-100 group as compared with NC group (p<0.05), The epididymal fat and retroperitoneal fat showed significantly lower weights and sizes in the OPE-4 and OPE-20 group as compared with NC group (p<0.05). The serum levels of total cholesterol, LDL cholesterol and triglyceride were significantly lower in the OPE-4 and OPE-20 group as compared with NC group (p<0.05). The OPE-4 and OPE-20 group showed higher HDL cholesterol concentration than NC group (p<0.05). Atherogenic index of OPE-4 and OPE-20 group was significantly lower in as compared with NC group (p<0.05). The serum levels of glucose significantly lower in the OPE-20 group as compared with NC group (p<0.05). Conclusions : In these results, we suggests that onion peel water extracts supplementation can reduces the serum lipid components and improves the lipid metabolism in hyperlipidemic SD rat induced with a high-fat diet.

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.131-137
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• 2013

The inhibitory effect of citrus peel extract, onion peel extract, calcium lactate and phosvitin on microbial growth was investigated in seasoned chicken breast meat during aerobic storage at $4^{\circ}C$, $10^{\circ}C$ and $20^{\circ}C$. Citrus peel and onion peel extract significantly improved (p<0.05) the microbial quality of the sample by reducing the initial counts of the microbial flora compared to control and other two treatments. Data clearly revealed that the counts of the total aerobic bacteria significantly increased with the increase in storage temperature. The shelf life of all samples stored under $20^{\circ}C$ was less than 6 days, while the shelf life of citrus and onion treatment can be extended more than 9 days at $4^{\circ}C$ and more than 6 days at $10^{\circ}C$ in aerobic storage condition. These results indicated that citrus and onion peel extracts are efficient treatment methods to prevent microbial spoilage of seasoned chicken products during storage at $4^{\circ}C$. However, there was an adverse effect of addition of citrus and onion peel extract on several sensory attributes which need to be improved by reformulation of seasoning.

• Journal of the Korean Dietetic Association
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• v.4 no.1
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• pp.14-19
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• 1998

This study was designed to investigate the role of onion as a natural antioxidant. Onion was distinguished as yellow onion peel and onion flesh. Onion samples were extracted with 5 different kinds of solvents such as water, 70% ethanol, 99.9%ethanol, 99.9% methanol, and 96% butanol in order to select optimal extraction solvents, In this part of study linoleic acid was used s an model system for the purpose of determining the antioxidant activities. The optimal extraction rate of various solvents containing onion samples was determined by measuring extraction yield, electron donating ability(EDA), thiobarbituric acid(TBA), and thiocyanate, which are common methods for measuring activity. As a result 70% ethanol was shown as the most effective solvent.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.364-368
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• 2014

This study investigated the antioxidant activity of onion peels extracted from onion byproducts by hot water treatment. Hot water extraction of freeze dried onion peel powder was analyzed for total polyphenol content, 2,2'-diphenyl-1-picryllhydrazyl (DPPH), and 2,2'-azino-bis(3-ehtylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities, reducing power, oxygen radical absorbance capacity (ORAC). Total polyphenol content was the highest (233.90 mg/g) in onion peel extract mix with ethanol (OPME-1). The DPPH radical scavenging activity ($IC_{50}$), reducing power, and ORAC obtainbed from onion peel extract mix with ethanol precipitation (OPMPE-1) were the highest at 1.15 mg/mL, 1.69 $A_{700}$, and $318,509{\mu}M\;TE/mL$, respectively. The ABTS radical scavenging activity was the highest at 432.78 mg amino acids (AA) eq/g in the OPM. The results of this study suggest that onion peel extracts have marked antioxidant activity, which can have significant health benefits.