• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.230-235
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• 2005

Volatile organic components from fresh and freeze-dried onions were extracted by SDE apparatus and analyzed by GC/MS. Components of 40 and 31 were identified in fresh and freeze-dried onions respectively. These components included esters, aldehydes, ketones, alcohols and S-containing compounds. Major compounds of S-containing compounds such as 1-propanethiol, dipropyl trisulfide, and methyl propyl trisulfide in fresh onions were clearly decreased in freeze-dried onions. Then, S-containing compounds such as methyl allyl sulfide, propyl ally sulfide, dially disulfide and 3,5-diethyl-l,2,4-trithiolane and alcohols such as pentanol, hexanol and propanol were disappeared by freeze-drying. Exceptionally, ethyl acetate, dimethyl disulfide and 2-methyl-2-pentenal were increased as different trend with major S-containing compounds. (Z)-Propenyl methyl disulfide and (E)-propenyl methyl disulfide were also changed by freeze-drying in the similar pattern as mentioned above compounds.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.5
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• pp.677-683
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• 2012

The characteristics and preservation of sulgi added with 0, 1, 3, and 5% onion juice were investigated during storage at $4^{\circ}C$, $18^{\circ}C$, and $30^{\circ}C$. The pH of sulgi added with onion juice was lower than that of sulgi without onion juice and showed higher pH levels at $4^{\circ}C$ than at $18^{\circ}C$ or $30^{\circ}C$. Hardness of sulgi gradually decreased with higher volume of onion juice. Sulgi added with onion juice had higher values of lightness and yellowness than those of the control, whereas redness value was lower. Water activity of sulgi increased upon addition of onion juice. Further, addition of onion juice inhibited growth of aerobic bacteria and mold on sulgi, and the highest suppression of microbial growth was observed at $4^{\circ}C$ compared to other storage temperatures. In the sensory evaluation, color, flavor, after swallowing, and overall quality were all higher in sulgi containing 1% onion juice, but there were no significant differences compared to control sulgi. These results imply that addition of onion juice to sulgi has health and functional benefits and also extends the self-life of sulgi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.342-347
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• 2007

Physicochemical properties of onion powder as influenced by drying methods were investigated. Moisture contents of onion powder were 13.29%, 12.99%, and 10.78% for samples dried using hot-air dryer, freeze dryer, and vacuum dryer, respectively. There were no significant differences in crude fat, crude protein, and crude ash content (p>0.05) depending on the drying methods. Samples prepared by freeze drying showed a significantly higher L-value as compared with those prepared by hot-air and vacuum drying (p<0.05). Scanning electron micrographs showed that freeze drying produced smaller particle-sized sample which in turn resulted in the higher porosity of the sample. Freeze dried samples revealed significantly lower degree of rehydration than other samples (p<0.05) probably due to small particle size of the sample. Water solubility of freeze dried sample appeared to be higher than that of other drying methods while the swelling ratio of the same sample appeared to be lower than that of the others. Browning index was significantly lower in samples prepared by freeze drying (p<0.05) but not significantly different between samples dried by hot-air and vacuum drying. Vitamin C content was higher in freeze dried onion powder due to the lower temperature applied to the sample. Freeze dried onion powder contained significantly lower amount of total polyphenol and higher amount of total sugar as compared to other samples (p<0.05).

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1043-1047
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• 2002

This study was carried out to investigate the effect of packaging materials (Ny/PE, PET/Al/PE, PET/PE/LDPE/CPP, PET/Al/Ny/CPP films, and bottle) and packaging methods (atmosphere and vacuum) on the physicochemical properties of Onion Kimchi and Rosemary-onion Kimchi stored at $5^{\circ}C$. Reducing sugar contents and pHs of Onion Kimchi and Rosemary-onion Kimchi decreased, whereas levels of titratible acidity and vit C contents increased with increasing the storage time. The fermentation of Rosemary-onion Kimchi was slower than that of Onion Kimchi. PET/PE/LDPE/CPP film was the most effective for Onion Kimchi packaging among all packaging materials tested.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1783-1789
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• 2010

The aim of this study was to examine the effects of 10 week onion extract supplementation on blood lipid profiles in borderline hypercholesterolemic participants. The study consisted of 10 males and 17 females aged $45.9{\pm}10.0$ years. At baseline, serum total cholesterol level was $228.6{\pm}4.1$ mg/dL (201~239 mg/dL). This study was designed as randomized single blind placebo controlled cross-over study. After 1 week wash-out period, subjects were randomized into two groups; they took onion extract (150 mL/1 pack, containing 30 mg quercetin) or placebo for 10 weeks. After 1 week wash-out period again, subjects took exchanged samples for another 10 weeks. The total-cholesterol ($226.7{\pm}4.6{\rightarrow}206.8{\pm}3.6$ mg/dL; p<0.01), LDL-cholesterol ($151.6{\pm}5.0{\rightarrow}127.1{\pm}4.1$ mg/dL; p<0.01) and atherogenic index (AI: $4.0{\pm}0.3{\rightarrow}3.4{\pm}0.2$; p<0.05) decreased significantly after 10 weeks of onion extracts supplementation, while there were no significant changes during placebo periods. The levels of HDL-cholesterol (onion extract: $46.5{\pm}2.0{\rightarrow}50.2{\pm}2.1$ mg/dL, placebo: $47.8{\pm}2.1{\rightarrow}50.1{\pm}2.4$ mg/dL), GOT (onion extract: $36.8{\pm}1.8{\rightarrow}32.3{\pm}1.8$ IU/L, placebo: $35.1{\pm}2.1{\rightarrow}32.8{\pm}2.0$ IU/L), and GPT (onion extract: $36.5{\pm}3.2{\rightarrow}32.9{\pm}1.8$ IU/L, placebo: $36.6{\pm}3.8{\rightarrow}33.8{\pm}2.8$ IU/L) showed no significant changes in both periods. These results indicate that the consumption of onion concentrated extracts exerts beneficial effects on dyslipidemia through the decrease of serum total cholesterol and LDL cholesterol levels in borderline hypercholestrolemic subjects. In conclusion, onion was useful as dietary therapy for hypercholestrolemia and adequate onion intake may help to prevent cardiovascular disease.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.368-371
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• 2001

This study was conducted to evaluate the effects of dietary onion supplementation on the growth rate and blood cholesterol level in finishing pigs. Sixty $Duroc\;{\times}\;Yorkshire\;{\times}\;Landrace$ pigs ($69.75{\pm}0.79kg$ average BW) were used in a 50 day growth assay. Dietary treatments included 1) corn-SBM (Con), 2) 1)+dietary onion rice bran 1.0% (ORB1), 3) 1)+dietary onion rice bran 2.0% (ORB2). For overall period, average daily weight gain and average daily feed intake were increased by the addition of dietary onion compared with Con (linear effect; p<0.01). Feed efficiency ratio was successfully improved by supplementation of dietary onion (linear effect; p<0.01). The total cholesterol concentrations in serum decreased as the concentration of onion in the diets was increased (linear effect, p<0.06). Also, LDL-cholesterol concentrations in serum tended to decrease in pigs fed onion than in those fed Con diet group (linear effect, p<0.04; quadratic effect, p<0.09). The HDL-cholesterol and triacylglyceride concentrations in serum were not influenced by the onion supplementation. The results obtained from this feeding trial suggest that the dietary onion supplementation for finishing pigs weighed 70 to 108 kg had improved growth performance and reduced total cholesterol level of serum.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.12
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• pp.1776-1783
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• 2016

Onions cultivated with (SY) or without (SN) sulfur application were stored for up to 36 weeks at $4^{\circ}C$ since harvest, after which they were analyzed for chemical composition and antioxidant activity in relation to sulfur (S) application and storage duration. Compared with SN onions, SY onions showed lower moisture and higher protein, soluble solids, and flavonoid contents at the time of harvest, and moisture and protein contents remained the same until 20 weeks of storage. However, soluble solids decreased while antioxidant activities, including flavonoids content, total reducing capacity, and superoxide dismutase (SOD)-like activity, appreciably increased as storage time increased to 20 weeks, which could be attributed to onion respiration and protective response to environmental stresses, respectively. There were abrupt decreases in flavonoid content and SOD-like activity at 36 weeks, presumably due to severe deterioration. Interestingly, all phenomena observed depending on storage time were independent of S application of onions. The results show that the critical factor influencing the chemical composition and antioxidant activity of onions during storage was postharvest storage duration rather than S application during onion cultivation.

• Food Science and Preservation
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• v.15 no.6
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• pp.796-803
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• 2008

To aid in manufacturing, this study investigated quality characteristics of onion Jangaji during maturation at 0C, 10C, 20C and room temperature. [Please check that the rewriting of the previous sentence retains the intended meaning]The $^{\circ}Brix$ of onion Jangaji and the maturation solution were 1516% at the end of the maturation process. The salinity of onion Jangaji and the solution increased, and the pH declined to 3.934.31 during processing. The L, a and b color values of onion Jangaji and the solution changed slightly. The total acidity of onion Jangaji and the solution rose slowly. The texture (hardness, fracturability, adhesiveness, cohesiveness, springiness, gumminess and chewiness) of onion Jangaji was determined using a texture analyzer, and varied with storage temperature. In the sensory evaluation of onion Jangaji, low temperature storage gave higher acceptability ratings than room temperature with respect to taste, color, flavor, texture and overall acceptability.

• Food Science and Preservation
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• v.15 no.6
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• pp.816-823
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• 2008

To develop onion processing, this study investigated the change in physicochemical properties of onion Jangaji with processing age in relation to the composition of the maturation solution (the solution). The Brix of onion Jangaji and the solution was high with addition of a high soy sauce ratio. During processing the salinity of onion Jangaji and the solution increased, and the pH decreased. The "L", "a", "b" color values of onion Jangaji and the solution changed slightly, and the total acidityrose slowly. The hardness, fracturability, adhesiveness, cohesiveness, springiness, gumminess and chewiness of onion Jangaji varied. In the sensory evaluation, the 100% sauce maturation solution received the highest acceptability ratings for color, flavor and taste.

• Journal of Life Science
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• v.18 no.9
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• pp.1271-1277
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• 2008

We investigated to determine the inhibitory effects of solvent extracts from dried onion on growth of cancer cell lines (HT-1080 human fibrosarcoma and HT-29 human colon cancer cells) and $H_{2}O_{2}$-induced oxidative stress. Two different drying methods, low temperature vacuum dryer and freeze dryer, were employed to dry onion. Inhibitory effects of acetone with methylene chloride (A+M) and methanol (MeOH) extracts from onion by two drying methods on the growth of HT-1080 and HT-29 cancer cells increased in a dose dependent manner (p<0.05) and the higher inhibitory effect was shown in onion extracts dried by low temperature vacuum dryer. The treatments of hexane, 85% aq. methanol, butanol and water fractions significantly inhibited the growth of both cancer cells (p<0.05) and onion fractions dried by freeze dryer showed a higher inhibitory effect compared with those dried by low temperature vacuum dryer. In order to determine a protective effect on H2O2-induced oxidative stress, DCHF-DA (dichlorodihydrofluorescin diacetate) assay was conducted. All fractions including crude extracts of dried onion appeared to significantly reduce the levels of intracellular reactive oxygen species (ROS) (p<0.05). Higher antioxidant effect was observed in onions dried by the low temperature vacuum dryer method. These results indicate that the low temperature vacuum dryer is useful to dry and produce onion powder.