• Food Science and Preservation
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• v.22 no.1
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• pp.12-18
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• 2015

The objective of this research was to investigate the antioxidant and antimicrobial activities of muscadine grape extracts. Three different cultivars of muscadine grapes including Higgings, Jumbo, and Noble were selected. The skin/pulp and seed parts of three selected muscadine grape cultivars were used for extraction. The total phenolic contents of muscadine grape extracts were expressed as gallic acid equivalents (GAE). The antioxidant activity of muscadine grape extracts were determined by scavenging activity of diphenylpicrylhydrazyl (DPPH) radical and expressed as effective concentration ($EC_{50}$), which represented the concentration of the extract exhibiting 50% DPPH radical scavenging. The antimicrobial activity against E. coli K12 was determined and expressed as the minimum inhibition concentration (MIC). The seed extracts exhibited greater total phenolic contents than the skin/pulp extracts, ranging from 231.24 to 294.81 mg/mL GAE. The seed extracts exhibited greater antioxidant activities than the skin/pulp extracts ($EC_{50}$ of Higgins seed extract=0.026 mg/mL). However, the skin/pulp extracts exhibited greater antimicrobial activities than the seed extracts, exhibiting the minimum inhibition concentration (MIC) in Higgins skin/pulp extract (MIC=4.0 mg/mL). This research indicated that the seed part and skin/pulp parts of the muscadine grapes possessed antioxidant activity and antimicrobial activity, respectively. Therefore, it was concluded that muscadine grapes possess the potential to be utilized as functional foods or nutraceuticals.

• Food Engineering Progress
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• v.13 no.1
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• pp.32-37
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• 2009

Central composite design was applied for the ultrasound-assisted extraction from peel and seed of Campbell Early grapes and the extraction processes were optimized for the antiradical activities of the extracts by using response surface methodology. Optimal conditions were 53.45% of ethanol concentration, 45.99${^{\circ}C}$ of extraction temperature and 23.93 min of extraction time for the maximum antiradical activity of grape peel extract (54.98%) and 53.14% of ethanol 56.03${^{\circ}C}$ of temperature and 29.03 min of time for maximum antiradical activity of grape seed extract (90.60%).

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.961-966
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• 2006

This study was worked out to investigate antioxidant activity of solvent extracts from wild grape skin by measuring electron donating ability (EDA), reducing power, superoxide dismutase (SOD)-like activity, thiobarbituric acid reactive substances (TBARS) and nitrite scavenging ability. Total phenolic compound and flavonoids contents were the highest in ethyl acetate extract, $54.4{\pm}1.18\;mg/100\;g$ and $645.1{\pm}5.05\;mg/100\;g$, respectively. The EDA and reducing power of solvent extracts from wild grape skin were proportionally increased with concentration and ethyl acetate extract $(79.2{\pm}0.06%)$ showed the stronger than BHT $(74.1{\pm}0.15%)$ at concentration of $100\;{\mu}g/mL$, especially. SOD-like ability of ethyl acetate $(25.1{\pm}0.41%)$ and butanol $(20.2{\pm}0.13%)$ extracts were stronger than other extracts at concentration of $100\;{\mu}g/mL$. TBARS of ethyl acetate extract was higher than ascorbic acid. Nitrite scavenging ability of solvent extracts from wild grape skin (pH 2.5, $1000\;{\mu}g/mL$) were in order of ethyl acetate $(90.5{\pm}0.75%)$>butanol $(65.9{\pm}2.16%)$>hexane $(58.1{\pm}1.74%)$>chloroform $(55.4{\pm}1.02%)$>water $(40.9{\pm}0.35%)$. Antioxidant activity of solvent extracts from wild grape skin was the highest in ethyl acetate extract from the results of our experiments.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2002.04a
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• pp.72.2-72
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• 2002

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.12
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• pp.1491-1496
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• 2007

As an oriental medicinal plant, wild grape (WG, Vitis coignetiae) has been known to contain abundant nutrients compared to grape (Vitis vinifera L.) and as a source of stilbenes, a kind of polyphenol. This study was performed to investigate the antioxidative activity of WG extracts by measuring electron donating ability (EDA), nitrite scavenging ability (NSA), super oxide dismutase (SOD)-like activity and total polyphenol content (TPC). The extracts were obtained using microwave-assisted extraction (microwave power: 90 W, extraction time: 5 min, extractant: water, 50 and 100% ethanol). EDAs, SOD-like activities and TPCs were the highest at 50% ethanol extracts while conversely lowest at 100% ethanol extracts. EDAs of 50% and 100% ethanol extracts at 1.6 g/dL concentration, $97.70{\pm}0.55\;and\;98.05{\pm}0.36%$, were higher than those of 0.1 and 1% L-ascorbic acids, $101.44{\pm}0.98%\;and\;99.43{\pm}0.78%$, respectively. At the concentration of 1.6 g/dL, 50% ethanol extract showed lower NSA (pH 1.2) than water extract unlike EDA, TPC and SOD-like activity. Regarding TPCs of WG extracts, the activities were the highest at 50% ethanol extracts (1.6 g/dL: $38.76{\pm}0.23$ mM gallic acid equiv.) followed by water and 100% ethanol extracts. The results suggest the usefulness of developing functional foods using antioxidative active compounds of WG with high polyphenol contents.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.576-585
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• 2003

An improved method in place of a conventional vanillin spectroscopic method (CVSM) was developed for determination of catechin and its derivatives in extract and oil of grape seeds. For the CVSM, grape seed extracts had relatively high catechin content in the range of $17{\sim}43%$ (g/100g of extract), while grape seed oils had relatively smaller catechin content in the range of $30{\sim}40mg%$ (mg/100g of oil). For the improved vanillin spectroscopic method (IVSM) using a polyamide cartridge, catechin content of grape seed extracts was in the range of $4.0{\sim}7.5%$, while that of grape seed oils was below 5 ppm. Meanwhile, the quantities of catechin and its derivatives were determined by HPLC in the grape seed extracts and oils. Four major catechins [(+)-catechin, procyanidin B2, (-)-epicatechin, and epicatechin gallate] were detected from grape seed extracts, and the ranges of concentrations were as follows: (+)-catechin, $1.35{\sim}2.60%$; procyanidin $B_2$, $0.77{\sim}1.36%$; (-)-epicatechin, $2.35{\sim}4.59%$; (-)-epicatechin gallate, $0.06{\sim}0.30%$. In contrast, four catechins were barely detectable in the grape seed oils. The reproducibility of four major catechins in grape seed extracts, given as coefficient of variation, was below 5%, and the recovery close to above 95%. The achieved detection level of four catechins was $1{\sim}5\;ppm$. Additionally, the contents of catechin compositions in grape seed extract were also determined by HPLC in relation to different cultivars and producing areas. Thus, HPLC method and IVSM using polyamide cartridge can be used as alternative to CVSM for determination of catechin and its derivatives in extract and oil of grape seeds.

• Food Science and Preservation
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• v.18 no.1
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• pp.119-123
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• 2011

In order to compare what kinds of transcription factors are associated with the inhibition of preadipocyte cell proliferation, we prepared several grape extracts and tested the expression patterns by reverse transcription-polymerase chain reaction. As a result, 50% ethanol extract of Campbell early seed inhibited adipogenesis derived from the MDI solution. Extract of Campbell early seed was significantly inhibited lipid droplet formation and expression of molecular factors C/EBP-alpha and delta in 3T3-L1 cells. It is suggested that grape extracts of fractions would be a good candidate for the development of regional skin fat modulator.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.884-888
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• 2007

The aim of this study was to analyze the antioxidant properties of different cultivars of grape skin extract in an in vitro system. The extracts were prepared from eight grape cultivars: 'Campbell Early' (CE), 'Kyoho' (K), 'New Kyoho' (NK), 'Muscat of Alexandria' (MOA), 'Seibel' (S), 'Morgen Schow' (MS), 'Gold Finger' (GF), and 'Meru' (M). The total phenolic acid contents were highest in MS and K. Resveratrol content was high in NK (50.88 mg/l g of coat), and quercetin content was significantly higher in K (0.68 mg/l g of coat) than in the other grape species (0.21-0.44 mg/l g of coat). The K and MS grape species, in which total phenol content was comparatively high (K: $24.15\;{\mu}g/mL$, MS: $25.52\;{\mu}g/mL$), also showed a high level of electron donating activity (K, 53%; MS, 59%). The hydrogen radical scavenging activity of M (50.36%) was significantly higher than the other grape species, including the S (50.21%), MS (49.43%), and K (49.06%) cultivars. Antioxidant activity varied depending on grape species, but overall it was highest in the MS and K cultivars.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.12
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• pp.1679-1683
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• 2008

The objectives of this study were to determine inhibitory effect on tyrosinase activity and antioxidant activity of the methanolic extract from grape seeds and to investigate relationships between tyrosinase inhibitory activity and antioxidant activity of the extract. The 80% methanol extracts of grape seeds were fractionated subsequently with hexane, chloroform, ethyl acetate and water. The methanolic extract and fractions from grape seeds inhibited tyrosinase activity in a concentration dependent manner. The methanolic extracts showed the highest inhibitory effects on tyrosinase activity. The inhibitory effects of the ethyl acetate fraction from the methanolic extract on tyrosinase activity was higher than other fractions. The ethyl acetate fraction from methanolic extracts showed higher antioxidant activity and contained higher polyphenolic and flavonoid contents compared to other fractions. The correlation coefficients among the polyphenoilc content of methanolic extracts, ABTS radical cation scavenging activity and inhibitory effect of tyrosinase were relatively high. These results suggest that grape seeds may have potential as a depigmentation agent for cosmetics and functional food products.

• Food Science and Preservation
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• v.15 no.6
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• pp.859-863
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• 2008

The proanthocyanidin content and antioxidant characteristics of seeds of grape cultivars were examined. Grape seeds were extracted in 70% acetone solution for 12 hr. The total phenolic content of the extracts ranged from 16.71 to 28.60 mg/100 g. The proanthocyanidin content ranged from 18.36 to 55.30 mg/100 g. The Jaok cultivar had the highest total phenolic and proanthocyanidin content, and showed the strongest antioxidant activity in the FRAP and DPPH assays. The total phenolic and proanthocyanidin content of grape seeds was correlated with their antioxidant capacities (r > 0.92). Acetone extracts of grape seeds could be effective antioxidant materials.