• Journal of Nutrition and Health
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• v.44 no.6
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• pp.488-497
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• 2011

Oxygen is necessary to sustain life, yet cellular oxygen metabolism creates destructive elements called free radicals. Free radicals are chemically unbalanced and carrying free electrons that can damage molecules, potentially damaging the cell itself. For this reason, many antioxidant products, including supplements and functional foods, are being developed. In particular, natural products are rich sources of pharmacologically active compounds. The purpose of this study was to investigate the antioxidant effects of target biomaterials in Korean traditional spices such as diallyl sulfide (DAS), capsaicin (CAP), and gingerol (GGR), and to investigate the response of the antioxidant defense system to oxidative stress by hydrogen peroxide ($H_2O_2$) compared to sulforaphane (SFN) in HepG2 cells. After the analysis of the cell viability using Cell Counting kit-8 (CCK-8) assay, we determined that the optimum levels were $200{\mu}M$ DAS, $25{\mu}M$ CAP, $50{\mu}M$ GGR, and $12.5{\mu}M$ SFN. Antioxidant enzymes were measured and protein expression was detected by Western blotting. All treatments showed a significant decrease in antioxidant enzyme activity such as superoxide dismutase, catalse, and glutathione peroxidase in HepG2 cells. Additionally, DAS, CAP, GGR and SFN increased the antioxidant system-related transcription factor Nrf2 which was found to be regulated by the activation of MAPK-JNK in this study. In conclusion, these results indicate the protective effects of DAS CAP, GGR, and SFN against $H_2O_2$-induced oxidative stress.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.96-104
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• 2003

Ginger (Zingiber officinale Roscoe) is traditionally used as appetite enhancer, improver of the digestive system, antithusive, anti-cold, antipyretic, analgesic, and antiinflammation. In vitro evaluation using human lymphocyte cultures showed almost similar indication with those in in vivo mouse study, NK cell lysing activity was improved significantly. Proliferation activity of B and T cells, and CD3$^{＋}$ and CD3$^{＋}$CD4$^{＋}$T cell subset were better observed using oleoresin or gingerol and shogaol fractions. Although there were higher activities in gingerol, the improvement was almost equal to that by oleoresin. Shogaol did not show better improvement except at higher concentration. It could be concluded that treatment with single bioactive compound, such as gingerol, did not show significant effects compared to oleoresin, the crude extract. In human study, involving healthy male adult, the improvement of NK cell lysing activity was again demonstrated and even more apparent. The mechanism involved in the protection seemed to be through the antioxidant activity of gingerol. However, other mechanism underlying the improvement of NK cell lysing activity must be involved since this improvement seemed to be specifically toward NK cell activity. Since NK cells ave specific for the elimination of virus-infected cell and mutated cells, this positive effect on the immune system are very interesting. This work has also scientifically proved that the traditional beliefs that ginger had preventive effects on common cold appeared to be reasonable.

• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.322-328
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• 2010

This study was conducted to examine the sensory attributes, gingerol content and volatile components of ginger paste resulting from microbial fermentation. In the ginger samples, a total of eighteen attributes were determined to characterize the sensory attributes from descriptive analysis. These eighteen attributes consisted of the following: one appearance, eight odor/aroma, eight taste, and one aftertaste attribute. The ginger fermented using Lactobacillus plantarum produced a ginger aroma and putrid taste, whereas the sample fermented with Lactobacillus brevis showed a decreased ginger aroma and taste, and generated a lemon flavor. A total gingerol content of fresh and fermented ginger was 100.19 mg% and 89.55 mg%, respectively. Sixty-one volatile components in the fresh and fermented ginger were identified, and constituted eight kinds of monoterpenes, twenty-one kinds of sesquiterpenes, eight kinds of oxygenated monoterpenes and nine kinds of oxygenated sesquiterpenes. The most abundant volatile component identified in the fresh ginger was $\alpha$-gingerberine (26.52%), whereas fermented ginger was increased in its alcohol components.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.404-412
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• 2011

This study was carried out to compare and analyze the active ingredients of Korean native ginger and rhizome derived from in vitro shoot-tip culture of Korean native ginger. Proximate compositions, mineral nutrients, free sugars, fatty acids, volatile components, 6-gingerol, and 6-shogaol were analysed and evaluated. Korean native ginger was proved to have a little more contents than in vitro rhizome in proximate compositions (crude ash, crude lipid, crude protein, carbohydrate). Mineral nutrient contents (Cu, Fe, Mn, Zn) of in vitro rhizome were higher than those of Korean native ginger. Among the mineral nutrients, the quantity of K was the highest, followed by P, Mg, Na, and Ca. Free sugar contents (fructose, glucose, sucrose) of in vitro rhizome were higher than those of Korean native ginger. Fatty acids containing less than C14 was the major among the fatty acids in ginger. Citral ingredient of the unique aromatic compound of Korean native ginger was stronger than that of the rhizome derived from in vitro shoot-tip culture. Gingerol concentration was increased by shoot-tip culture.

• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.264-272
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• 2023

The aim of this study was to compare the antioxidant activities and functional contents of Korean conventional and Chinese seed gingers from the Jeollabuk-do Wanju and Chungcheongnam-do Seosan regions. Ginger samples were subjected to steaming treatments for different durations (2-8 h) at 121℃ using an autoclave. The antioxidant activity was evaluated by measuring total polyphenol and flavonoid contents and ABTS and DPPH radical scavenging activities, while functional ingredient contents were analyzed for gingerols and shogaols. The results showed that Wanju conventional seed ginger (WO-2) had the highest total polyphenol (85.24 mg GAE/g) and flavonoid (98.14 RE/100 g) contents, surpassing that of the control in all steamed groups at 6 h. ABTS radical scavenging activity showed a strong correlation with total polyphenol and flavonoid contents. The control groups indicated that Korean conventional seed ginger had 1.0-1.3 times higher gingerol contents compared to Chinese seed ginger. Furthermore, the content of shogaols, considered major functional ingredients, increased significantly with longer steaming durations, reaching the highest content (1,793 mg/kg) at 8 h, which was 1.0-1.8 times higher in Korean conventional seed ginger than that in Chinese seed ginger. These experiments provide valuable data supporting the excellence of Korean conventional seed ginger in the future.

• Nutrition Research and Practice
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• v.5 no.5
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• pp.412-420
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• 2011

The aim of the present study was to investigate the hypocholesterolemic effect and potential of tyramine derivatives from Lycii Cortex Radicis (LCR), the root bark of lycium (Lycium chenese Miller) in reducing lipid peroxidation. The activities of enzymes, hepatic 3-hydroxy 3-methylglutaryl (HMG) CoA reductase and acyl-CoA:cholesterol acyltransferase (ACAT) and LDL oxidation were measured in vitro and animal experiments were also performed by feeding LCR extracts to rats. The test compounds employed for in vitro study were trans-N-p-coumaroyltyramine (CT) and trans-N-feruloyltyramine (FT), LCR components, N-(p-coumaroyl)serotonin (CS) and N-feruloylserotonin (FS) from safflower seeds, ferulic acid (FA) and 10-gingerol. It was observed that FT and FS at the concentration of 1.2 mg/mL inhibited liver microsomal HMG CoA reductase activity by ~40%, but no inhibition of activity was seen in the cases of CT, CS, FA and 10-gingerol. Whereas, ACAT activity was inhibited ~50% by FT and CT, 34-43% by FS and CS and ~80% by 10-gingerol at the concentration of 1 mg/mL. A significant delay in LDL oxidation was induced by CT, FT, and 10-gingerol. For the animal experiment, five groups of Sprague-Dawley male rats were fed high fat diets containing no test material (HF-control), 1 and 2% of LCR ethanol extract (LCR1 and LCR2), and 1% of extracts from safflower seed (Sat) and ginger (Gin). The results indicated that total cholesterol level was significantly lower in Saf, LCR2 and Gin groups, and HDL cholesterol level was lower only in Gin group when compared with HF-control group; while there was no difference in the serum triglyceride levels among the five experimental groups. The level of liver cholesterol was significantly lower in LCR1 and LCR2 groups than HF-control Serum levels of TBARS were significantly lower only in LCR2 group when compared with HF-control group. From the observed results, we concluded that LCR can be utilized as a hypocholesterolemic ingredient in combination with ginger, especially for functional foods.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.166-171
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• 2012

6-Shogaol, a dehydrated form of 6-gingerol, is a minor component in ginger (Zingiber officinale Roscoe) and has recently been reported to have more potent bioactivity than 6-gingerol. Based on the thermal instability of gingerols (their dehydration to corresponding shogaols at high temperature), we aimed to develop an optimal process to maximize the 6-shogaol content during ginger extraction by modulating temperature and pH. Fresh gingers were dried under various conditions: freeze-, room temperature (RT)- or convection oven-drying at 60 or $80^{\circ}C$, and extracted by 95% ethanol at RT, 60 or $80^{\circ}C$. The content of 6-shogaol was augmented by increasing both drying and extraction temperatures. The highest production of 6-shogaol was achieved at $80^{\circ}C$ extraction after drying at the same temperature and the content of 6-shogaol was about 7-fold compared to the lowest producing process by freezing and extraction at RT. Adjustment of pH (pH 1, 4, 7 and 10) for the 6-shogaol-richest extract (dried and extracted both at $80^{\circ}C$) also affected the chemical composition of ginger and the yield of 6-shogaol was maximized at the most acidic condition of pH 1. Taken together, the current study shows for the first time that a maximized production of 6-shogaol can be achieved during practical drying and extraction process of ginger by increasing both drying and extracting temperatures. Adjustment of pH to extraction solvent with strong acid also helps increase the production of 6-shogaol. Our data could be usefully employed in the fields of food processing as well as nutraceutical industry.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.249-254
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• 2011

Applying ginger to processed foods to improve health is limited due to its pungent odor. In this study, fermented gingers were prepared using lactic acid bacteria from dairy products or kimchi and their chemical and sensory properties were examined. Adding dried ginger or fermented gingers (GSt, GLa, GLm) to plain yogurt made them less tasty and lowered the overall acceptability of yogurt except GLp. For all fermented gingers including GLp, the characteristic flavors of the ginger decreased by fermentation so adding fermented ginger into yogurt did not affect its flavor significantly. Thus GLp would be expected to be a food ingredient instead of dried ginger without lowering organoleptic qualities. The content of 6-gingerol, a bioactive component in ginger, decreased in all fermented gingers. However, 6-shogaol, which increased in GSt, GLa, and GLm, was not detected in GLp.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.469-474
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• 2011

Ginger (Zingiber officinale Rosc.) is a well known edible plant that is traditionally used to treat various illnesses related to inflammation and oxidative stress. Steam distillated ginger oil or water extract are mainly used for related products; however, it is unclear whether these fractions contain most of the bioactive compounds or the highest efficacy. This investigated the antioxidant effects of extracts prepared by supercritical fluid extraction (SFE). 6-Gingerol was the most abundant component in hexane fraction of ethanol extract from ginger. The antioxidative properties of SFE oil and Marc ethanol fractions were demonstrated using the 2,20-diphenylpicrylhydrazyl (DPPH) and 2,2'-azinobis 3-ethyl benzothiazoline-6-sulfonic acid (ABTS) radicals scavenging assays. A clear correlation was observed between total polyphenol contents and $RC_{50}$ values in the Marc ethanol fraction. These results indicate that not only SFE oil but the marc after SFE could be good sources for the food industry.

• Journal of Life Science
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• v.28 no.2
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• pp.153-161
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• 2018

Hot-air and freeze dried powder from aged black ginger were mixed under the ratio conditions of sample "A" (8:2), "B" (5:5), "C"(2:8), "D" (10:0) and "E" (0:10), respectively. The physicochemical properties and antioxidant activities in the 5 kinds of powder were compared. The water absorption index was significantly higher in freeze dried powder, and it tended to be significantly increased depend on the ratio of freeze dried sample. The browning intensity was significantly higher in the hot-air dried samples, but the color intensity was not significant. Total and reducing sugar contents were significantly higher in freeze dried sample. Total sugar content in mixed sample tended to significantly increased as the amount of freeze dried sample. Total phenol content was significantly higher in the sample "A". The contents of gingerol and shogaol were significantly higher in mixed sample "A", 6-gingerol content showed no significant difference according to the drying method. Cholesterol absorption activity was significantly higher in the freeze dried sample "E". The DPPH radical scavenging activity showed a little difference according to the drying method, but the ABTS radical scavenging activity and reducing power in the hot-air dried sample were significantly higher than those of freeze dried. And the activity of mixed powder "A" was significantly higher than others. These results suggest that aged black ginger was superior in terms of quality and functionality of the hot-air drying compared to freeze-drying, and it would be economically effective to the mixed sample "A".