• Food Science and Preservation
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• v.30 no.5
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• pp.833-846
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• 2023

Onions are essential vegetables for Koreans' diet and have various physiological activities. However, problems arise every year due to the imbalance between production and demand. Therefore, in this study, nutritional and functional components, and antioxidant activity were analyzed for each growth period in order to utilize onions at the disposal period. Whole onions harvested before June showed higher values of general ingredients, inorganic ingredients, organic acids, spiraeoside, quercetin, total chlorophyll, and antioxidant activity than bulbs harvested in June. On the other hand, the free sugar content was higher in the bulb of the harvest season in June than in whole onions. The total thiosulfinate content was similar to that of whole onions and bulbs in the early stages of growth. In addition, as a result of comparing the flavonoid compound and antioxidant activity of each onion variety, whole onions harvested at 25 weeks were higher in content than onion bulbs harvested in June. In conclusion, onions before the harvest season in June had excellent utilization value as food. Harvesting before 21 weeks is desirable for growing onions with excellent nutritional value, while harvesting after 23 weeks is recommended for excellent functional components and antioxidant activity in onions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.12
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• pp.1784-1791
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• 2016

Garlic was subjected to eight different cooking methods (raw, boiling, steaming, microwave cooking, deep-frying, oven-roasting, pan-frying, and pan-roasting) utilized for typical Korean cuisine. Garlic was analyzed for antioxidant activities and physicochemical properties to elucidate effects of cooking. Garlic cooked at higher temperatures showed significantly lower lightness and higher yellowness (P<0.001). In particular, deep-frying and pan-frying resulted in lowest lightness and soluble solid content, indicating that non-enzymatic browning reactions were more facilitated. Compared with raw garlic, all cooked garlic tended to have lower thiosulfinates, presumably due to decomposition into polysulfides and/or leaching into cooking water and oil. Microwave cooking retained organic acids, total reducing capacity, and flavonoids, which can be attributed to low microwave intensity and shorter cooking time under which heat-labile bioactive components might have undergone less decomposition. Cooking significantly increased metal-chelating activity (P<0.001). In addition, oven-roasting and pan-roasting enhanced total reducing capacity and flavonoid content, indicating that thermal treatments increased the extractability of bioactive components from garlic. However, boiling, deep-frying, and pan-frying, in which garlic is in contact directly with a hot cooking medium, reduced antioxidant activities. Deep-frying resulted in largest reduction in DPPH radical scavenging activity of garlic, which correlated well with reduction of total reducing capacity and flavonoid content. The results show that the antioxidant activity of garlic could be affected by cooking method, particularly heat intensity and/or direct contact of the cooking medium.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.301-306
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• 2001

An invistigation was carried out to study the effects of heat treatment of garlic and storage temperature of garlic extracts on functional properties of garlic extracts. The garlic was heated at 40, 60, 80, 100, $120^{\circ}C$ for 10 minutes and extracted with 50% ethanol. The extracts were stored at 4, 25 and $50^{\circ}C$ for 30 days, and then electron donating ability(EDA), nitrite-scavenging effects(NSE) and total thiosulfinates contents were determined. Among the functional properties, total thiosulfinates were rapidly reduced as the heating and storage temperature increased. The total thiosulfinates in the extracts were not detected for those heat-treated at 100 and $120^{\circ}C$. The EDAs were also decreased to almost half of their initial level by heat treatment of garlic at higher temperature than $80^{\circ}C$ while NSE was decreased a little. As the storage temperature increased, EDA and thiosulfinate contents decreased. Particularly the thiosulfinates were ditected none after 11 days of storage at $25^{\circ}C$ and $50^{\circ}C$. Therefore, mild heat treatment of garlic at lower temperature than $60^{\circ}C$ and storage at refrigerated condition are recommendable for preparation and storage of garlic extracts.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.103-114
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• 2011

Physicochemical characteristics of garlic collected from the different growing regions were analyzed to provide basic data for preparing nutritional composition of garlic. Moisture of garlics on cultivars from growing on China was $71.53{\pm}0.34%$ that significantly higher than domestic garlics ($59.37{\pm}0.63$-$66.92{\pm}0.72%$). Total phenol contents were $12.69{\pm}0.18$-$22.02{\pm}0.27mg/100g$, total flavonoids contents were $12.69{\pm}0.18$-$22.02{\pm}0.27mg/100g$. Total thiosulfinate and pyruvate contents were $96.28{\pm}2.55$-$150.81{\pm}0.09mg/100g$ and $132.87{\pm}0.45$-$161.37{\pm}1.58mg/100g$. Sucrose, glucose and fructose were detected from garlics, sucrose content average errors about 2-4 times due to cultivated area. Namhae garlic has the highest fructose contents than other province cultivated. 8 kinds of organic acids 11 kinds of mineral and 17 kinds of composition amino acids were detected in garlics. 5 kinds of free amino acids such as proline, alanine, tyrosine, phenylalanine and arginine were detected in all garlic samples.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.357-365
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• 2011

This study was conducted to compare biological activity of browning compounds from fresh, red and black garlic. Water soluble browning compounds were separated from fresh, red and black garlic by dialysis membrane. Antioxidation and other biological activities of freeze dried inner and outer parts from garlics were compared. pH of fresh and red garlic dialysis solutions were higher in inner part of membrane, but black garlic dialysis solution showed reverse tendency. Browning intensities of all tested samples were higher in outer part of dialysis solutions. In inner part dialysis solutions, contents of total phenol compounds were the lowest in red garlic while their contents were the highest in black garlic and thereafter, were the highest in inner part of dialysis solution made from red garlic. Flavonoids content was the highest in inner part of red garlic dialysis solution. Total pyruvate content was higher in outer part of fresh and red garlic dialysis solution which showed the opposite results in black garlic. Total thiosulfate content was the highest in black garlic, red garlic and fresh garlic in order. Antioxidant activities have some similarities among garlic products. DPPH radical scavenging activity was higher in inner part of fresh and black garlic and outer part of red garlic. Tyrosinase inhibition activity was higher in browning compounds of red garlic than fresh and black garlic. $\alpha$-glucosidase inhibition activity of tested samples were higher in inner part of dialysis solution than outer part, and showed higher activity in red garlic than fresh garlic at low sample concentrations.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.507-513
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• 2001

An effective extraction methods of a garlic were investigated in order to improve the functional properties of the extracts. The solid yield, electron donating ability (EDA), nitrite-scavenging effects (NSE), peroxide value (POV) and total thiosulfinates contents of garlic extracts were determined. In order to improve the functional properties of extracts prepared with several organic solvents and acids, concentration and pH adjustment of the selected solvent and addition of acids and salts to solvents were also examined. Among the solvents tested, the methanol and ethanol extracts were found to be the most effective on the base of functionality and solid yields. The highest EDA, NSE and thiosulfinate value were obtained with 50% ethanol. The pH control of solvent and addition of citric acid, NaCl and phosphates to 50% ethanol did not affect on the functionality of the extracts. Therefore the optimal solvent for the best functional properties of garlic extract was 50% ethanol.