• Proceedings of the Korean Society of Life Science Conference
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• 2000.09a
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• pp.37-37
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• 2000

• Culinary science and hospitality research
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• v.14 no.1
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• pp.144-151
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• 2008

This study investigated the changes in the contents of allicin and diallyl disulfide and in the alliinase activity during the vacuum freeze drying of onion samples treated as the whole, sliced and crushed forms. The contents of allicin and diallyl disulfide in raw onions were 26.40ppm and 2.78ppm respectively. The contents of allicin and diallyl disulfide of onion samples treated as the whole, sliced and crushed forms increased with the progress of vacuum freeze drying. The degree of increase was different in each onion sample form prepared by vacuum freeze drying(p<0.05). The specific activity of alliinase in raw onions was 7.536 units/mg protein. The activity in onion samples treated as the whole, sliced and crushed forms decreased with the progress of vacuum freeze drying. The activity in the whole onion prepared by the vacuum freeze drying for 8 hrs reduced to 5.516 units/mg protein with 73.2% remaining and to 3.304 units/mg protein with 43.8% remaining for 36 hrs. The activity in the sliced onion prepared by the vacuum freeze drying for 36 hrs reduced to 2.366 units/mg protein with 31.4% remaining and the activity in the crushed onion prepared by the vacuum freeze drying for 36 hrs reduced to 2.232 units/mg protein with 29.6% remaining. The alliinase in onion sample treated as the whole form showed the highest remaining activity during the vacuum freeze drying.

• Korean Journal of Food Science and Technology
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• v.40 no.4
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• pp.389-393
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• 2008

This study examined the effects of cooking temperature and onion (Allium cepa L.) tissue concentrate on heterocyclic amine (HCA) formation in fried ground beef patties. Various amounts of onion tissue (2.0, 5.0, and 10.0%, w/w) were added to the ground beef patties, which were then fried at two different temperatures (190 and $225^{\circ}C$) for 10 min/side. The ground beef patties fried at $190^{\circ}C$ and containing 10.0% (w/w) onion showed a 51% decrease in mutagenicity, and formation of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP) was reduced by 58% and 63%, respectively. For the patties fried at $225^{\circ}C$, total mutagenicity decreased by 35% and 48% with the additions of 5.0 and 10.0% (w/w) onion, respectively, and PhIP formation was reduced 50, 60, and 71% with the additions of 2.0, 5.0, and 10.0% (w/w) onion, respectively.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.522-527
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• 2010

Onion has been reported to contain various organosulfur compounds which have antibiotic and anticarcinogenic properties and flavonoid like quercetin which is a valuable natural source of antioxidants. Carbohydrates in onion constitute about 80% of dry matter, and the major non-structural carbohydrate of onion bulb is fructo-oligosaccharides, well known as fructan, followed by glucose, fructose, and sucrose. The sugar concentration is associated with dormancy and storage life of onion, occurring as decrease in glucose, fructose and fructan, particularly towards the end of storage. Forced air pre-drying for 15-20 days at room temperature is an essential procedure to reduce freezing injury and sprouting, then onion bulbs can be stored at $0^{\circ}C$ for 6 months to control sprouting and decay. Bacterial soft rot caused by $Erwinia$ and $Pseudomonas$ is the main postharvest disease when the bulbs are infected with the bacteria and stored at room temperature. Browning in sliced onion is due to oxidation of phenolic compounds by polyphenol oxidase and it can be inhibited by citric acid treatment, packing with nitrogen gas, and polyethylene film.

• 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.

• The Korean Journal of Mycology
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• v.20 no.4
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• pp.302-308
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• 1992

Seven genera and 15 species of fungi were isolated from 50 samples of then different steps of dried onion (5 samples of each step) collected from an onion factory in Sohag Governorate, Egypt, and grown on glucose-Czapek's agar (7 genera and 15 species) and 10% NaCl glucose-Czapek's (2 genera and 6 species). The average total counts of fungi were gradually decreased throughout the different steps of drying from 2090 to zero and 152 to zero colonies/g on glucose-Czapek's agar and 10% NaCl glucose-Czapek's agar media, respectively. Aspergillus was the most common genus on the two types of media used. The dominant species were Aspergillus niger, A. flavus, A. terreus, Penicillium chrysogenum and Fusarium of oxysporum on glucose-Czapek's agar and A. terreus and A. niger on 10% NaCl glucose-Czapek's agar. The chloroform extracts of different samples were tested for the presence of mycotoxins using thin layer chromatographic analysis. The results indicated that aflatoxin was present at concentrations decreased throughout the different steps of the drying from step No. 1, onion bulbs, $120\;{\mu}g/kg$; to step No. 8, standard A, $20\;{\mu}g/kg$ while step Nos. 9 & 10 (completely dry powdered onion) were free from aflatoxin. Citrinin was also present in the first three steps at concentrations gradually decreased from 30 to 10 mg/kg.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.470-474
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• 2011

The objectives of this study were to identify antioxidant substance in heated onion. The isolation of active compound was performed in three steps: silica gel column chromatography, preparative TLC, and preparative HPLC. The structure of the purified compound was determined using spectroscopic methods, i.e., ultraviolet, mass spectrometry, $^1H$-NMR, $^{13}C$-NMR, and DEPT. The antioxidant activities of isolated compound were evaluated and compared with $\alpha$-tocopherol, ascorbic acid, and butylated hydroxytoluene (BHT) using DPPH and ABTS assay. The isolated compound was identified as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one(DDMP). The DPPH radical-scavenging activity ($IC_{50}$) of the DDMP was in the following order: ascorbic acid (45.3 ${\mu}g/mL$)>$\alpha$-tocopherol (69.2 ${\mu}g/mL$)>DDMP (241.6 ${\mu}g/mL$)>BHT (268.0 ${\mu}g/mL$). In addition, DDMP showed strong ABTS radical-scavenging activity of 569.0 mg AA eq/g.

• Food Science and Preservation
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• v.7 no.1
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• pp.19-22
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• 2000

This study was carried out investigate the storability of onions on calcium spraying, after cutting foliage, 6 different treatemnt , the dilution spraying of calcium nitrate 9 3%, 6%) , calcium carbonate(3%, 6%), dust scattering and the controls were evaluated for rotting, sprouting, healthy bulb and total weight loss ratio during storage. Rotting ratio on the dilution spraying of 6% calcium carbonate was lower than that of the control after 4 months storage by 16.7%. Sprouting and total weight loss were decreased in the dilution spraying of 6% calcium carbonate.

• Food Science and Preservation
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• v.20 no.1
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• pp.134-139
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• 2013

This study was conducted to develop healthy foods or natural preservatives with garlic (Allium sativum L.), ginger (Zingiber officinale R.) and onion (Allium cepa L.). The polyphenol contents of garlic, ginger and onion juice were analyzed, and they were tested for antioxidative and antibacterial activities. Their antioxidative activities were investigated in terms of their electron donating activity (EDA), SOD-like activity and nitrite scavenging ablity (NSA). Their antibacterial activities were tested against four kinds of pathogenic bacteria (L. monocytogenes, S. aureus, E. coli O157:H7, and Sal. typhimurium). The yields of the garlic, ginger and onion juice were 28.2, 24.3 and 38.3 percent, and their total polyphenol contents were 1,254, 1,523 and 412 mg/100 mL, respectively. The EDAs of the garlic and ginger juice ranged from 95 to 98 percent and over 90 percent in the 40 percent diluted solution. Their SOD-like activities were 64 and 67 percent, repectively. Onion juice had lower activities in EDAs and SOD-like activity than those of garlic and ginger juice. The NSAs of the garlic, ginger and onion juice were 56.5, 52.4 and 50.2 percent, respectively. The garlic juices showed antibacterial activity against four kinds of pathogenic bacteria (L. monocytogenes, S. aureus, E. coli O157:H7 and Sal. typhimurium) and the highest such activity against Sal. typhimurium. From all the results of the experiments, it can be concluded that garlic, ginger, onion can be used as a natural preservatives and can help develope healthy foods because of their antibacterial and antioxidative activities and abundunt polyphenols.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.476-482
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• 2001

This experiment was conducted to evaluate the effect of slow-release fertilizer application on quality elevation of onion (Allium cepa L.) in southwestern sea. The slow-release fertilizers used were NIAST (National Institute of Agricultural Science and Technology) I, II, CDU (Crotonylidene Diurea), UF (Urea-Formaldehydes), and IBDU (Isobutylidene Diurea) 30, 50. Growth of the onion plant treated with slow-release fertilizer showed better than the control. However, a rate of infected plant to downy mildew was low as compared with control. Chlorophyll and total nitrogen contents were high in control, whereas firmness, soluble solid content, number and thickness of scaly leaves were high in slow-release fertilizer plot. In early maturing onion, total marketable bulb yield was higher in slow-release fertilizer plot than all other fertilizer treatments. Total marketable bulb yield in late maturing onion treated with slow-release fertilizer was slightly decreased. Decaying loss and the rate of sprouting during storage period decreased in slow-release fertilizer application. In summary, application of slow-release fertilizer increased marketable yield, storability after harvest and also reduced labor needs for top dressing.