• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.8
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• pp.1206-1211
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• 2015

Grape juice is consumed worldwide and studied due to the high antioxidant activities and contents. The color of grape juice is due to the presence of phenolic compounds such as anthocyanins. Therefore, color values can be an indicator of antioxidant capacities of grape juice. However, the correlation between color values and antioxidant activities in grape juice has not been well studied. In this study, the physicochemical characteristics and correlation between color values and antioxidant capacities of Korean red grape juices (five commercial juices from market and two juices prepared in the laboratory) were investigated to estimate antioxidant capacities. Antioxidant capacities were determined by 1,1-diphenlyl-2-picrylhydrazyl radical scavenging assay, ferric ion reducing antioxidant power assay, and oxygen radical absorbance capacity assay. Total phenolic contents, total flavonoid contents, and total anthocyanin contents, including five kinds of polyphenolic compounds, were examined by high performance liquid chromatography (HPLC). The results for physicochemical properties showed similar values, except titratable acidity. The color hue values of the prepared juices were higher than those of commercial juices, which was in contrast to the lower color intensity values (P<0.05). The Hunter L, a, and b values showed almost no difference between commercial and prepared juices. The antioxidant activities and total phenolic contents of commercial juices were higher than those of prepared ones. Gallic acid, catechin, and quercetin were confirmed by HPLC in all samples. The total phenolic and total flavonoid contents showed positive correlation with antioxidant activities. In addition, antioxidant activities and contents correlated with color values. Thus, estimation of antioxidant capacity could be feasible through the spectrophotometric measurement of color values.

• The Korean Journal of Food And Nutrition
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• v.28 no.4
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• pp.628-634
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• 2015

The ground red pepper puree was treated with cellulase (C treatment), pectinase (P treatment), amylase (A treatment) and/or enzyme complex (CP, CA, PA and CPA treatment) for 2~8 hours to improve the yield and bioactivity of extracts. And physicochemical and sensory properties of red pepper extracts were evaluated. The extraction yield of the control was 38.84%, which was lower than those of the enzyme treatments. And extraction yields of enzyme complex treatments were higher than that of single enzyme treatments. Especially, extraction yield was increased to 74.37% by cellulase + pectinase + amylase complex treatment (CPA treatment). The soluble solid and reducing sugar contents were higher in the extracts treated with enzymes compared with the control. CA and CPA treatment showed the highest soluble solid and reducing sugar contents. No significant changes in lightness, redness and yellowness of the control and the samples by enzyme treatments were observed during 2~8 hours experiments. The sensory evaluation results revealed that panelists preferred the extracts with enzyme treatments to the control. Therefore, enzyme treatment for red pepper extracts is a good method to improve the yield and sensory properties.

• Journal of the Korean Society of Food Culture
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• v.3 no.4
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• pp.385-390
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• 1988

This study was conducted to determine the interconversion of sugars in persimmon during the drying process and the textural properties of raw and dried persimmons using the changes of some chemical constituents, the analysis of sugar component, and the measurement of texture. Five varieties of persimmons were used in this experimment. As the drying proceeded, content of acetaldehyde and alcohol increased while soluble tannin content rapidly decreased. The rapid changes of these component obserbed in kyongsan Bansi and Hiratanenashi. Soluble sugars detected in raw persimmons were mainly glucose, fructose and sucrose. The content of sucrose was rapidly decreased in early stage of drying, while glucose and fructose were rapidly increased. The nearly same amount of glucose and fructose presented in the dried persimmon although there were some differences among varieties tested. The major component of white powder developed on the surface of dried persimmon was almost glucose. The texture profile analysis of the raw and dried persimmons was made with texturemeter and the quality of the dried persimmons was sensory evaluation method. Hiratanenashi and Sagoksi were determined as the suitable varieties in the processing of dried persimmons, but the varieties of Changdungyee and Namyang Susi were not suitable.

• Culinary science and hospitality research
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• v.20 no.6
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• pp.223-234
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• 2014

The present study relates to the development of a processed product for expansion of use of Tangor which is mostly eaten raw in winter. Furthermore, Tangor jam containing fructo oligosaccharide and isomalto oligosaccharide was prepared, and thus quality characteristics of the jam have been determined according to the sugar concentration by making a low-sugar jam by adding substitute sweeteners instead of sugar, because low-sugar products are recently preferred in the market. Furthermore, the general elements of flesh and rind of Tangor, DPPH free radical scavenging activity, chromaticity, sugar content, pH, acidity, and preference have been checked. As a result of the experiment, the chromaticity, luminosity (L), the sugar content, and pH were the lowest in the control group. In F1, F2, and F3, which gradually added fructo oligosaccharide, and I1, I2, and I3, which slowly added isomalto oligosaccharide, luminosity significantly increased with the addition of oligosaccharide. In contrast, as the amount of addition of oligosaccharide increases, red chromaticity (a), yellow chromaticity (b), and sugar content have significantly decreased. Lastly, in the preference test using a 9 point test scheme, F2 and I2 have been considered most appropriate when producing Tangor jam.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1347-1355
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• 2015

In this study, the physicochemical properties, antioxidant capacities, and volatile flavor compounds of oriental melon wine prepared by freeze concentration after heat treatment (HA), ascorbic acid treatment (AAT), and heat and ascorbic acid treatment (HAAT) were investigated. During fermentation period, the melon wine by HAAT showed greater reduction of soluble solids and reducing sugar contents compared to other treatments. In addition, the melon wine treated with HAAT also showed a higher L value and lower browning index compared to other treatments. After aging, free sugar including fructose, and organic acids including citric acid, succinic acid, and malic acid were detected in all samples. For antioxidant activities and contents, HAAT treated wine showed greater antioxidant activities and total phenolic contents than those of others. In GC/MS analysis, a total of 33 volatile flavor compounds were identified. In the principal component analysis of volatile flavor compounds, principal components 1 and 2 represented 88.15% of the whole date distribution and showed opposite tendencies. Taken together, HAAT enhanced the antioxidant activities and sensory properties of oriental melon wine. Moreover, freeze concentration gave the different volatile flavor characteristics in oriental melon wine.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1819-1825
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• 2010

This study was carried out to investigate the quality characteristics of ginseng JungKwa produced with hot-water extract from Maegmundong (MGJ) instead of sugar. Chemical characteristics of MGJ and control ginseng JungKwa produced by sucrose (CGJ) were measured by proximate constituents, free sugars, ginsenosides, total phenolic compound, flavonoid content, and antioxidative activity was measured by electron donating abilities and hydrogen peroxide scavenging activity. Carbohydrate, crude protein, crude ash contents of MGJ were 76.40, 1.46 and 3.49%, where as those of CGJ were 80.01, 0.59 and 0.96%. Free sugar compositions of MGJ were fructose (32.42%), oligosaccharide (16.91%), disaccharide (13.91%) and glucose (13.16%). Eleven ginsenosides types were detected on MGJ and 9 kinds on CGJ; their contents were 740.1 and 675.6 mg%, respectively. Total phenolic compound and flavonoid content were 5.46 and 0.016% on MGJ, 5.02 and 0.014% on CGJ, respectively. In physiological characteristics, the $IC_{50}$ of electron donating ability by DPPH on MGJ was about 34.5 mg/mL and ability was slightly higher than CGJ, although there's not much difference in ability between MGJ and CGJ. Hydrogen peroxide scavenging activities were 92% on MGJ and 96% on CJG when treated at $50{\mu}g$/mL.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.2
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• pp.145-152
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• 2002

To compare the Carbon metabolic response to high temperature stress in Zoysiagrass [Zoysia matrella (L.) Merr.] and Creeping bentgrass (Agrostis palustris Huds) with respect to heat tolerance, C metabolites were determined from April to September. Sampling was carried out on an established golf course (Muan Country Club, Chonnam, Korea). Shoot mass(g Dry weight per hole cup) of creeping bentgrass started to decrease from June and recovered from August whereas that of zoysiagrass was less varied. Chlorophyll content in creeping bentgrass was significantly higher than zoysiagrass until July, and then decreased by 43% from July to August. Zoysiagrass contained higher soluble sugar than creeping bentgrass throughout experimental period. Soluble sugar in zoysiagrass increased about 58% from April to May, and less varied until August. Soluble sugar in creeping bentgrass slightly increased until July and sharply decreased at August. Starch concentration in zoysiagrass continuously decreased to September after a significant increase from April to May. A remarkable fluctuation in both starch and fluctuation concentration was observed between June and August showing high accumulation for June to July and high degradation for July to August. These results suggest that through creeping bentgrass suffers much severely from high temperature stress than zoysiagrass especially June to August. An active accumulation and degradation in nonstructural carbohydrate in creeping bentgrass during this period might be associated with heat stress.

• Food Science and Preservation
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• v.10 no.1
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• pp.60-64
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• 2003

This paper was performed to identify and determine dietary fibers considered as nutracerticals and for pharmaceuticals in Korean fruits, citron, jujube and persimmon. In the pulp and peel of citron, jujube and persimmon, the contents of dietary fiber were determined by the method of AOAC and Van Soest et al. The contents of dietary fiber(DF) in the pulp of citron were 2.61％ of insoluble dietary fiber (IDF) and 1.25% of soluble dietary fiber(SDF) based on wet weight. The contents of DF in the peel of citron were 7.32% of IDF and 0.71％ of SDF. The total pectin contents in the pulp and in the peel of citron were 1.77% and 3.19% respectively. The contents of IDF in the pulp of jujube were 2.98%, SDF 0.91 ％ calculated on wet weight basis. The contents of IDF were 16.88%, SDF 1.53% in the peel of jujube. The contents of DF in the pulp of persimmon were 1.95% of IDF and 0.31 ％ of SDF based on wet weight. The contents of IDF were 15.71 ％, SDF 2.46% in the peel of persimmon. In dietary fibers of Korean fruits, citron, jujube and persimmon, IDE were much higher than SDF and mainly in the pulp. Therefore, they would be good source of dietary fibers.

• Food Science and Preservation
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• v.17 no.2
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• pp.202-207
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• 2010

The effects of ultrasound treatment, in combination with ascorbic acid, on the quality of fresh-cut 'Jonathan' apples was investigated. Prepared apple slices were ultrasonicated in distilled water (US) or in 1%(w/v) ascorbic acid solution (UA) and the other samples were just dipped in 1%(w/v) ascorbic acid solution (AA). All samples were stored at$10^{\circ}C$ for 12 days. UA-treated samples showed high $L^{*}$ and hue values and low $a^{*}$, $b^{*}$, chroma, and ${\Delta}E$ value. Both control and US-treated samples showed considerable browning. A significant inhibition of polyphenol oxidase activity was observed after UA treatment. The level of total phenolics in UA-treated samples was higher on the day of treatment compared with other samples. Total soluble solids, pH, titratable acidity, and gas concentrations were similar in all samples. This study demonstrated that the simultaneous treatment of ultrasound and ascorbic acid was effective in preventing enzymatic browning of fresh-cut 'Jonathan' apples and maintaining total phenolics contents.

• Food Science and Preservation
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• v.30 no.1
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• pp.155-169
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• 2023

Jerusalem artichoke (JA, Helianthus tuberosus L.) has a great potential to enhance the quality of yakju due to the plentiful inulin content which is functional and indigestible carbohydrate in human. In this study, the optimal preparation conditions such as the added amount and steam treatment of JA were investigated to improve the quality of yakju. As the amount of JA added to yakju increased, alcohol production decreased, whereas fermentation was performed well when the steam-cooked JA was added to yakju. The pH and total acidity of yakju decreased and increased, respectively, when the amount of JA added to yakju increased, whereas pH and total acidity of yakju increased and decreased, respectively, when the steam-cooked JA was added to yakju. The free sugar and organic acid contents of yakju increased and decreased, respectively, when the amount of JA added to yakju increased, whereas those of yakju decreased when the steam-cooked JA was added to Yakju. Amino acid content of JA decreased as the amount of JA added to yakju increased and that of JA significantly decreased when the steam-cooked JA was added to yakju. In the sensory evaluation analysis, the addition of 10% unsteam-cooked JA to yakju was the best when considering sweetness, flavor, sourness, and overall preference of yakju supplemented with JA. Consequently, utilizing JA to yakju may contribute to the improvement of the quality of yakju.