• Journal of Dairy Science and Biotechnology
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• v.34 no.4
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• pp.263-270
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• 2016

This study was carried out to evaluate the antioxidant activity and total polyphnol content of Greek-style yogurt in 12% solid content with added stevia leaf extracts. Stevia leaf extracts used as sweetener in preparing Greek-style yogurt were prepared in hot water ($100^{\circ}C$ for 6 h 3 times, and by 70% fermented ethanol for 24 h at room temperature 3 times). The antioxidant activities were measured by assessing the radical scavenging effect through DPPH, ABTS, and FRAP assays. To identify the compounds present, total polyphenol content was evaluated using a Folin-Dennis assay. The capability to scavenge free radicals and total polyphenolic content were the highest in Greek-style yogurt containing 1% stevia extract and fermented in 70% ethanol. According to the results, antioxidant activities significantly increased when high concentration of stevia extracts were added to the yogurt (p<0.05). Therefore, these results suggest that stevia leaf extracts can be used as a source of functional compounds in Greek-style yogurt. We also suggest that fermented ethanol extraction can be used to obtain stevia leaf extracts.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.363-367
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• 2014

In this study, the dietary fiber contents of Mozuku (Cladosiphon novae-caledoniae kylin) residue and the extraction condition (HCl, $H_2SO_4$, NaOH, $Na_2CO_3$, $Na_2EDTA$) of the dietary fiber was investigated. We examined that the contents of the total polyphenols and flavonoids in the dietary fiber from Mozuku residue, and the potent anti-cancer effect was also tested through the growth inhibition in human colon cancer cells (HT-29) in vitro. It was effective to extract soluble dietary fiber with 1.5% $Na_2EDTA$ and 0.05 N HCl in Mozuku residue. The extraction time and temperature affected the yields of soluble dietary fiber. The contents of the total polyphenols and flavonoids in the dietary fiber from Mozuku residue were the highest in 1% NaOH extract (Total polyphenols $34.4{\pm}0.055$ mg gallic acid/g dry basis, total flavonoids $34.7{\pm}0.023$ mg naringin/g extract dry basis). In DPPH radical scavenging activity, 1% NaOH extract showed the most potent antioxidant activity. In the result of viability in human colon cancer cells, growth inhibition was observed in D.W., 0.05 N HCl, and 0.5% $Na_2CO_3$ extracts in a dose-dependent manner. These results demonstrated that soluble dietary fiber from Mozuku residue significant antioxidant activity and anticancer in human colon cancer.

• Journal of Ginseng Research
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• v.30 no.1
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• pp.41-48
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• 2006

In the browning reaction of Korean ginseng, it appears that enzymatic and non-enzymatic browning reaction occurred In initial stage of steaming fresh ginseng at low temperature, and then non-enzymatic browning reaction followed in the drying period after steaming. Browning reaction of red ginseng occurred between $60{\sim}90$ min of steaming at $100^{\circ}C$, and browning pigments of red ginseng were mostly water soluble substances. The structural characteristics of water soluble browning reaction products(WS-BRPs) isolated from Korean red ginseng were showed the presence of hydroxyl, amide carbonyl and aliphatic methane groups. From sugar analysis it was identified that L and S-1, melanoidins isolated from red ginseng, contained two kinds of sugars, glucose and xylose, and the other melanoidin S-2 contained the previous and fructose. In order to find out pertinent methods for the acceleration of browning during ginseng processing, various treatment were made on fresh ginseng with sugars, amino acids and inorganic nitrogenous compounds and the extent of browning was measured. Among sugar tested, maltose resulted in the greatest acceleration of browning followed in decreasing order by glucose and lactose, whereas pentoses, fructose, sucrose and raffinose had negligible effect. A marked browning occurred in ginseng treated with basic amino acids, while the extent of browning was not greatly increased when ginseng was treated with aliphatic amino acids, hydroxyl amino acids, or acidic amino acids. The brown color intensity gradually increased with an increase of glucose concentration far up to 0.5M. L, S-1, and S-2 were found to have an ability to donate hydrogen to DPPH, and also they had anti-oxidative activity in the experiments of hydrogen peroxide scavenging, inhibitory activity in the formation of MDA from linoleic acid, auto oxidation of ok-brain homogenates, lipid peroxidation by the enzymatic and non-enzymatic system in liver microsome fraction, and mitochondrial fraction etc. The amounts of acidic polysaccharide(AP) in red ginseng were higher than those of wild and cultured Panax quinquefolius, Panax notoginseng as well as white ginseng (Panax ginseng). In white ginseng, the AP amount is no difference in root ages or sizes, also, the AP amount of ginseng body was similar to that of rhizome, but was higher than that of leaf and epidermis. Addition of red ginseng acidic polysaccharide(RGAP) increased production of nitric oxide(NO) and tumor necrosis factor (TNF)-$\alpha$ in the rodent macrophage cultures, and treatment of RGAP in vivo stimulated tumoricidal activities of natural killer (NK) cells.

• Food Science and Preservation
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• v.20 no.5
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• pp.621-627
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• 2013

This study was conducted to investigate the effect of Curcuma longa L. powder (CLP) on the quality characteristics of a dumpling shell. Dumpling shell samples were prepared with wheat flour and different amounts of CLP were added to them, after which their instrumental characteristics and sensory evaluation were investigated. The gelatinization temperature of the CLP-wheat flours composite increased, whereas its initial viscosity at $95^{\circ}C$, viscosity at $95^{\circ}C$ after 15 min and maximum viscosity all fell with the increasing CLP content, as measured via amylography. As increasing amounts of CLP were added, the L value decreased, whereas the a and b values increased. With regard to the textural characteristics, the CLP additive became harder, more cohesive and adhesive, and less springy. The DPPH free radical scavenging activity increased significantly as the CLP content increased (p<0.05). Overall, the dumpling shells with 3% CLP were preferred over the other samples, as tested via sensory evaluation.

• Journal of Life Science
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• v.19 no.8
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• pp.1132-1138
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• 2009

We investigated the physicochemical stabilities and biological activities of ethanol- extracted pigment from marine bacterium Pseudoalteromonas psicida TA20. This bacterial pigment was very stable at a pH range of between 4.0 and 8.0 at a temperature below $40^{\circ}C$. In the presence of light, the pigment was also very stable, showing more than 90 percent remaining absorbance during 14 days at $25^{\circ}C$. The stability of the pigment, when metal ions were present, showed higher stability in all examined metal ions except for $Al^{3+}$ and $Cu^{2+}$, especially in the presence of $Fe^{2+}$. This pigment showed higher stability than other pigment extracts reported. The pigment has free-radical scavenging (3,495 ${\mu}g/ml$) activity and 44% antioxidant protective effect against DNA damage of human lymphocyte cells at a concentration of 10 ${\mu}g/ml$. The results indicate that the bacterial pigment produced a significant reduction in oxidative DNA damage. The pigment also showed antimicrobial activity against major food poisoning bacteria. Therefore, these results suggest that this bacterial pigment could be used as a natural colorant in the food industry, having the advantages of antioxidant and antimicrobial activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.622-629
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• 2017

This study was carried out to investigate the effects of cold maceration and heat treatment prior to alcohol fermentation on the quality characteristics of wine made from Okrang grape cultivar. The results of this study show that alcohol contents of wines increased as fermentation period increased, whereas $^{\circ}Brix$ values decreased. The pH levels of wines ranged from 3.17 to 3.42 while the total acidities of wines ranged from 0.49~0.99%. The free sugar contents of wines tended to decrease as fermentation period increased. In particular, free sugar content of wine pre-treated at low temperature prior to alcohol fermentation slowly. Total polyphenol content of wine heat-treated prior to alcohol fermentation was higher than those of other wines and reached a maximum value after fermentation for 2 days. Campbell Early wine showed the strongest antioxidant effect, measured based on DPPH free radical scavenging activity, followed by Okrang wine pressing after fermentation. These results indicate that pre-treatment before wine fermentation greatly affects wine quality and biofunctional activities.

• Food Science and Preservation
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• v.14 no.4
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• pp.385-393
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• 2007

Much research is conducted on the biological activities of medicinal herbs, traditional plants, and agricultural products, cultivated in Korea. This study focused on optimization of hot-water extraction methods for such products, by analyzing and monitoring extraction characteristics using a response surface methodology. We found that the total phenolics contents, electron-donating abilities, and nitrite-scavenging abilities of extracts were significantly affected both by the solvent used for extraction, and by the nature of the particular herb or plant under study. The extraction efficiencies of valuable ingredients such as alliin, allicin, and total thiosulfinate, were greatly affected by extraction temperature, but not by extraction time or the solvent used. We elicited a regression formula for each variable. We first entered the optimal values of all extraction conditions giving active ingredients into the model. Next, we entered the optimal values of all extraction conditions favoring the retention of valuable antioxidant characteristics. Finally, we entered processing factors into the model. Overall, the optimal extraction was at $80^{\circ}C$ for 3.5 hr with 8.5 ml of solvent/g of sample. The predicted values of each variable were similar to the actual values.

• Food Science and Preservation
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• v.20 no.4
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• pp.475-481
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• 2013

This study was performed in order to compare the changes in fruit quality and antioxidant activity depending on the ripeness degree of the banana flesh and peel (unripe, ripe, and over ripe) when stored at room temperature for 6 days. The moisture contents showed differences such as the significantly lower maturity in the over ripe fruit peel and the moisture content increase in the fruit flesh during ripening. During the maturity stage, the L and b values decreased, while the a value increased. During ripening, the titratable acidity (TA) decreased, while the soluble solids contents (SS), sugar acid ratio (SS/TA), total sugar, and reducing sugar contents increased, respectively. Also during ripening, the glucose and the fructose contents increased considerably, thus resulting in the decrease of the sucrose content. In addition, this study revealed that the phenolic substance, which was part of the fruit skin, showed more favorable reaction to radical ability than the fruit flesh. Furthermore, the DPPH, ABTS radical scavenging ability, and reducing power showed better reaction for the fruit skin than for the fruit flesh, and there was a significant increase in the antioxidative activity as a result of the higher levels of phenolic substance. Therefore, maturity played an important role in changing the chemical composition and physiological activity of a banana. The unripe peels could be used as antioxidant ingredients and they could also enhance the biological activity in the utilization of by-products.

• Food Science and Preservation
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• v.15 no.3
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• pp.332-339
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• 2008

This study was performed to investigate the sorption characteristics and shelf-life of coated ascorbic acid Stability of ascorbic acid, which oxidizes easily during storage and processing, was achieved by applying a fluidized bed coating using Zein-DP and HPMC-FCC as covering materials. The monolayer moisture content calculated using the GAB equation showed a higher level of significance than when calculated using the BET equation. The fit to the isotherm curve was in the order of Halsey, Caurie, Oswin and Khun. The equilibrium relative humidity prediction model was established in terms of time and water activity, it had higher significance. The stability of the coated ascoribic acid during storage was investigated in terms of radical-scavenging activity, which decreased with increasing time of storage and was more affected at higher storage temperatures. The quality reduction rate constant (k) was calculated by a first-order reaction rate. The reaction rate constant increased with increasing storage temperature. The shelf-life of Zein-DP-coated ascorbic acid was estimated to be 45.83 days at 20C and 63.19 days at 10C, and the shelf-life for HPMC-FCC-coated ascorbic acid was estimated to be 28.84 days at 20C and 36.14 days at 10, the ascorbic acid was 24.52 days at $20^{\circ}C$ and 27.22 days at $10^{\circ}C$, respectively. Therefore, the fluidized bed coating effectively increased the stability of ascorbic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1357-1362
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• 2013

The objective of this study was to evaluate the effects of far-infrared (FIR) irradiation on the antioxidant and tyrosinase inhibitory activities of Schizonepeta (S.) tenuifolia. After FIR irradiation of S. tenuifolia for 30 min at 70, 90, or $110^{\circ}C$, water extracts (2 g/100 mL) were prepared at $60^{\circ}C$ for 1, 3, or 5 h. Total phenol content (TPC), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activities (RSAs), and tyrosinase inhibitory activity of the extracts were determined. TPC, antioxidant and tyrosinase inhibitory activities of the extracts increased significantly with increasing FIR irradiation temperature of S. tenuifolia. For example, irradiation at $110^{\circ}C$ for 5 h increased TPC, DPPH RSA, ABTS RSA, and tyrosinase inhibitory activity of the extract from 204.64 to $618.67{\mu}g$ gallic acid equivalents/mL, from 30.15 to 80.84%, from 24.43 to 55.33%, and from 7.05 to 33.65%, respectively, compared to the extract of untreated S. tenuifolia. These results indicate that FIR irradiation may be useful as a processing method for enhancing the quality of S. tenuifolia.