• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.596-602
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• 2014

We investigate the quality characteristics and free radical scavenging ability of yanggaeng prepared with different amounts of grape juice (GJ). GJ was incorporated into yanggaeng at different levels (containing 50, 100, 150, and 200 g of GJ in yanggaeng, respectively) based on the total weight of water. Sugar contents showed a significant increase; however, pH showed a decrease with increasing levels of GJ. In terms of color, lightness and yellowness decreased significantly but redness increased with increasing levels of GJ. In a texture profile analysis, hardness were increased; however, springiness, cohesiveness, gumminess, and chewiness decreased with increasing levels of GJ. Total polyphenol content and 1,1-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity increased significantly as the GJ concentration increased in the formulation. The sensory evaluation indicated that yanggaeng containing the 150 g level of GJ showed the best preference in terms of color, taste, texture, flavor, and overall acceptance. These results suggest that grape juice may be a useful ingredient in yanggaeng to improve quality and antioxidant potential.

• Journal of Nutrition and Health
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• v.36 no.2
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• pp.125-132
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• 2003

The present study was attempted to investigate and compare the antioxidant potency of several well-know flavonoids, antioxidant vitamin and commercially available popular beverages. The antioxidant potency was assessed by the effect on reducing oxidative DNA damage of human lymphocytes. Cellular oxidative DNA damage was measured by SCGE (single-cell gel electrophoresis), also known as comet assay. Lymphocytes were pre-treated for 30 minutes with wide ranges of doses of apigenin, kaempferol, luteolin, myricetin, rutin, quercetin, $\alpha$-tocopherol (10,25,50,100,200,500,1000 $\mu$M) ,green tea extract or grape juice (10,50,100,250,500,1000 $\mu$g/mL) followed by a $H_2O$$_2$(100 $\mu$M) treatment for 5 min as an oxidative stimulus. The physiological function of each antioxidant substance on oxidative DNA damage was analyzed as tail moment (tail length $\times$ percentage migrated DNA in tail) and expressed as relative DNA damage score after adjusting by the level of control treatment. Cells treated with $H_2O$$_2$alone (positive control) had an extensive DNA damage compared with cells treated with phosphate buffered saline (PBS, negative control) or pre-treated with all the tested samples. Of all the six flavonoids, quercetin was the most potent antioxidant showing the lowest $ED_{50}$/ of 8.5 $\mu$g/mL (concentration to produce 50% protection of relative DNA damage). The antoxidant potency of individual flavonoids were ranked as follows in a decreasing order; luteolin (18.4 $\mu$g/mL), myricetin (19.0 $\mu$g/mL) , rutin (22.2 $\mu$g/mL) , apigenin (24,3 $\mu$g/mL) , kaempferol (25.5 $\mu$g/mL). The protective effect of $\alpha$-tocopherol was substantially lower (highest $ED_{50}$value of 55.0 $\mu$g/mL) than all the other flavonoids, while the protective effect was highest in green tea and grape juice with low ED5O value of 7.6 and 5.3, respectively. These results suggest that flavonoids, especially quercetin, and natural compounds from food product, green tea and grape juice, produced powerful anti-oxidative activities, even stronger than $\alpha$-tocopherol. Taken together, supplementation of antioxidants to lymphocytes followed by oxidative stimulus inhibited damage to cellular DNA, supporting a protective effect against oxidative damage induced by reactive oxygen species.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1527-1527
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• 2001

Glucose, fructose and sucrose being the main sugars that can be found in natural fruit juice. Many instrumental methods, such as GC, LC, electrochemical or spectrometric methods provide information about both the total content of sugars and the specific concentration of each carbohydrate[1]. The simplicity of sample handling and measurement in the near IR(NIR) wavelength region, which allows the use of long pathlength, optical glass cells and optical fibers, makes NIR a good alternative for sugar determination [2]. In the present study, six varieties of persian grapes were harvested at intervals through august to october and analysed for sugars by NIR. The results were processed by principal component regression (PCR) and partial least squares (PLS) analysis. Sample juice was prepared by squeezing through gauze from crashed grape. This solution was treated by zinc ferrocyanide prior to analysis in order to eliminate colored compounds and all optically active nonsugar substances. For glucose and fructose the most characteristic wavelengths were 1456nm corresponding to the first harmonic O-H stretching and the second at 2062nm corresponding to O-H stretching and deformation; secondary characteristic combination bands were also seen at 2265 nm (O-H and C-C stretching) and at 2240 nm (C-H and C-C stretching). However these spectra were taken over a wavelength range from 1100-2500nm at room temperature of 25-$30^{\circ}C$. To test the accuracy of the described procedure, samples of six varieties of grape were analysed by the proposed NIR and a standard method[2]. Good agreement were found between these two sets of the results. To perform the recovery studies , samples of grape juices previously analysed by the proposed method, were spiked with known amounts of each individual sugars and then analysed again. Relative standard deviations varied from 1.4 to 1.8% for six independent measurements of individual and total sugar concentration. In the analysis of real and synthetic samples, precise and accurate results were obtained , providing accuracy errors lower than 1.9% in all cases. Average recoveries of ${97}{\pm}{4%}$ for total sugar and between ${95}{\pm}{5%}$ and ${99}{\pm}{2%}$ for sing1e sugars demonstrate the applicability of the methodology developed to the direct analysis of grape Juice.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.496-502
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• 2013

Grapes (Vitis vinifera) are one of the most important fruits worldwide and are eaten raw or after conversion to jelly, jam, juice and wine. Grape skins are a major source of resveratrol (3,5,4'-trihydroxystilbene), which has the ability to reduce blood sugar as well as anticancer, anti-inflammatory, and other beneficial cardiovascular effects. In this study, we investigated the increased accumulation of resveratrol in grape skin and leaves following ultrasonication treatment, which has been shown to induce resveratrol accumulation in several plants. Various ultrasonication treatment times and incubation periods were employed to identify the optimum conditions for the maximum accumulation of resveratrol. Treatment and further incubation led to increased resveratrol in both grape skins and leaves, with the highest increases of 7.7-fold and 1.9-fold occurring in response to 5 min ultrasonication treatment followed by 6 hour incubation and 15 min ultrasonication treatment followed by 3 hour incubation, respectively. The underlying mechanism for the increased amounts of resveratrol were studied by employing a semi-quantitative RT-PCR to monitor the expression levels of the resveratrol synthase (RS) gene in response to ultrasonication treatment. The RS gene increased the expression in response to ultrasonication treatment, suggesting that up-regulation of the RS gene by ultrasonication treatment triggers increased amounts of resveratrol. Taken together, these data indicate that this simple ultrasonication treatment of grapes can be an efficient post-harvest technology for increasing resveratrol in grape skins in addition to cleaning the fruits.

• The Korean Journal of Community Living Science
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• v.22 no.3
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• pp.417-427
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• 2011

This research obtained fundamental data for the development of grape foods by investigating the preference for grape foods, popularization and commercialization plan of grape foods and obtained knowledge required in order to develop grape foods. The study used 354 consumers in Seoul and GyeongGi Province. The distribution of sex on research subjects was as follows. Male was 52.0% (184 persons) and female was 48.0% (170 persons). Age distribution varied by twenties and less than twenties being 30.8%, thirties being 26.3%, forties being 24.6% and the fifties and over being 18.4%. According to the results, preference for grape foods of subjects was that rice wrapped in grape leaves ($2.14{\pm}0.7$) and sweet steamed rice($2.12{\pm}0.8$) were the highest among staple food; grape vinegar($2.38{\pm}0.7$) and grape taffy($2.25{\pm}0.7$) were the highest among spices; grape jelly ($2.53{\pm}0.6$) and grape pudding($2.45{\pm}0.7$) were the highest among snacks; grape juice ($2.70{\pm}0.5$) and grape yogurt($2.59{\pm}0.6$) were the highest among beverages. Subjects responded to the fruit group among food groups harmonized with grape foods(p<0.01). 50.7% of subjects responded to "have to be delicious" and 25.1% of subjects responded to "nutritional balance" as the most important aspects of the development of grape foods. In the popularization and commercialization plan of grape foods, Subjects chose with respected importance, personal preference($4.15{\pm}0.8$), price($4.05{\pm}0.8$) and promotional strategy($4.00{\pm}0.9$). In conclusion, the food development and revitalization plan should use grapes to find out food materials suitable for grape mixture and nutritional balance. We will expect an increase population and commercialization of grape foods if we develop grape foods and promote strategically in consideration of the preference of consumers and the price of produce.

• The Journal of Advanced Prosthodontics
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• v.12 no.2
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• pp.55-60
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• 2020

PURPOSE. The aim was to evaluate the effect of four acidic beverages on the roughness (Ra) and color change (ΔE_ab) of two brands of artificial teeth and a heat-polymerized acrylic resin (HPAR) for use in a prosthetic base. MATERIALS AND METHODS. All materials were divided into 5 groups, according to the used acidic beverage (artificial saliva - control, red wine, orange juice, coke-based, and lemon juice-based soft drink). The immersion process was divided into two stages: T1 - immersion in the acidic solutions for 10 minutes for 14 days; T2 - after T1, the samples were immersed in grape juice for 14 days. The Ra of the samples was evaluated in a rugosimeter and the ΔE_ab in a spectrophotometer, before and after the immersions. The analysis of variance of one (ΔE_ab) and two factors (Ra) and Tukey were performed (α=.05). RESULTS. There was a statistical difference for roughness after immersion (T1) for Trilux and Tritone teeth, regardless of the acid solution. For Trilux teeth, all acid solutions increased Ra (P<.05). For Tritone teeth, only the coke-based soft drink did not statistically change Ra. Grape juice (T2) altered Ra only of artificial teeth (P<.05). The color was changed for all materials, after T1 and T2. CONCLUSION. In general, the acidic solutions changed the Ra and ΔE_ab of HPAR and artificial teeth after T1. The grape juice altered the roughness only of the artificial teeth, promoting a clinically acceptable color change in the materials.

• Applied Biological Chemistry
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• v.14 no.1
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• pp.1-7
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• 1971

In order to develop an enzyme preparation for clarification of fruit juices, a microbial strain having a strong pectolytic activity was selected and a crude enzyme preparation from this strain was examined for the effects in the preparation of grape juice and wine. The results are summarized as follows: 1) A strain of Aspergillus niger was selected as having the highest productivity of pectolytic enzymes among many species of Aspergillus and Rhizopus. 2) A pectolytic enzyme preparation was purified from this selected strain and the effects of pH and temperature on its enzyme activity and stability were investigated. 3) The use of the enzyme preparation brought about the increase in the free run yield and clarity of grape juice. 4) Whereas the use of the enzyme preparation did not exhibit any effect in the brewing of red wine, its use showed a good effect on the rates of filtration and clarity in the case of white wine.

• Food Science and Preservation
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• v.18 no.5
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• pp.811-816
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• 2011

Cryoextraction (a freeze concentration using an instrument) can increase the sugar concentration in grape juice by reducing its water content, similar to the natural freezing of grapes for natural ice wine. In this study, fermentation of freeze-concentrated Campbell Early grape (Vitis labruscana) juice to 36 $^{\circ}Bx$ was carried out using Saccharomyces cerevisiae strains D8 and S13 isolated from Korean grapes. During the fermentation, strains S13 and D8 showed rapid sugar reduction and alcohol production compared with S. cerevisiae Fermivin$^{(R)}$ used as a control. After nine-day fermentation, the residual sugar contents were lower in W13(9.77%) and D8 wine(9.07) than that in Fermivin$^{(R)}$ wine(14.0%). Total acid content was high in the D8>S13>Fermivin$^{(R)}$ wine, in that order. The acetaldehyde content was highest in the D8 wine and lowest in the Fermivin$^{(R)}$ wine, among the three. The methanol content was slightly higher in the S13 and D8 wines than in the Fermivin$^{(R)}$ wine. In the sensory evaluation, the S13 wine exhibited the highest score in flavor and taste among the three wines. Both the two S13 and D8 wines exhibited higher scores than Fermivin$^{(R)}$ wine in overall preference.

• Food Science and Preservation
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• v.20 no.6
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• pp.846-853
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• 2013

We investigated the effect of the cell-wall-degrading enzyme and its skin contact time on the brewing characteristics of Cheongsoo grape. The easy of juice extraction was excellent at the cell-wall-degrading enzyme and skin contact treatments, and the aroma was best after five days of skin contact treatment. Furthermore, the juice yields of the Chengsoo grape were more dramatically increased by the cell-wall-degrading enzyme and skin contact treatments than by the control. The data on the pH, total acidity, and soluble solids did not significantly differ among the treatments, and the pH range from 3.1 to 3.4; the total acidity from 0.5% to 0.6% (as tartaric acid); and the soluble solids, from 6.7 to 7.1 $^{\circ}Brix$. The alcohol content of cell-wall-degrading enzyme treatment was highest with 13.3%. The total polyphenol was gradually increased with the longer skin contact time, and was highest after 10 days of skin contact treatment, at 306.4 mg/L. The main organic acids detected in the Cheongsoo wine were malic and tartaric acid, and citric, succinic and lactic acid were also detected. Our results show that the cell-wall-degrading enzyme and skin contact treatments were better in terms of the easy of juice extraction and significantly increased the juice yield and the volatile compound of the Cheongsoo wine.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.650-659
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• 2014

Large quantities of Korean wild grape (Vitis coignetiae, KWG) pomace, a by-product of grape juice and wine manufacture, are generated annually, and disposal cost of KWG pomace is now increasing. Therefore, this study was conducted to determine total polyphenol, flavonoid, and anthocyanin content in whole KWG, KWG skin and KWG pomace and to identify and quantify flavonoids found in whole KWG and KWG pomace using LC/MS/MS. Spectral analysis showed high total polyphenol and flavonoid in KWG skin extracted with 75% ethanol (p < 0.05). KWG pomace had higher amount of total polyphenol, flavonoid and anthocyanin than whole grape (p < 0.05). Sixteen flavonoids were identified, but only 10 flavonoids were quantifiable from whole KWG and KWG pomace. Both epicatechin and rutin were the major flavonoids, and 521 or 147 ng/g of epicatechin (p < 0.05) and 305 or 110 ng/g of rutin (p > 0.05) were found in whole KWG and KWG pomace, respectively. The results show that KWG pomace is a very rich source of flavonoids, thus KWG pomace can be used as a functional food additive. Plans to include KWG pomace in food production are necessary.