• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.889-899
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• 2017

To investigate the quality characteristics of domestic $ros{\acute{e}}$ wines marketed in Korea, 11 kinds of wines were purchased at the Korea Wine Festival in 2016. The color, physiological activity, aroma component and sensory evaluations were conducted. The hue value of $ros{\acute{e}}$ wines ranged from 0.592 to 1.990, with the Ro7 of Delaware having the highest value. The brightness of $ros{\acute{e}}$ wines ranged from 42.96 to 94.99, the redness from 3.20 to 59.37, and the yellowness from 8.43 to 24.83. Of the 11 $ros{\acute{e}}$ wines evaluated, 1 was a dry wine and 10 were sweet wines. The average sugar content of the sweet wines was 73.89 mg/mL. Among the organic acid contents, malic acid ranged from 0.214 to 2.903 mg/mL, and lactic acid content ranged from 0 to 3.423 mg/mL. Malolactic fermentation differed, depending on the source. The total polyphenol content of $ros{\acute{e}}$ wines ranged from 50.55 to 99.55 mg%, the anthocyanin content was 2.12 to 213.30 mg/L, and the DPPH radical scavenging activity of $ros{\acute{e}}$ wines was between 73.75 to 90.41%. A total of 41 volatile components were detected, including 7 alcohols, 22 esters, 4 terpenes, 3 acids and 5 other compounds. Of these, 9 compounds had odor activity value(OAV) greater than 1; these were identified as 1-propanol (alcohol, pungent), 3-methyl-1-butanol (harsh, nail polish), ethyl butanoate (strawberry, lactic), isopentyl acetate (fresh, banana), ethyl hexanoate (green apple, fruity), ethyl octanoate (pineapple, pear, floral), ethyl decanoate (fruity, fatty, pleasant), linalool (flower, lavender) and limonene (lemone, orange). As a result of the sensory evaluation, the Ro5 wine made from Campbell Early grape, and having a good color, flavor and taste, was the most preferred.

• Food Engineering Progress
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• v.14 no.1
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• pp.14-20
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• 2010

The objective of the current study was to determine the cryoprotective effects of trehaolse on lactic acid bacteria in the frozen yoghurt during long-term frozen storage conditions. The frozen yoghurts were prepared using starter culture containing Lactobacillus bulgaricus and Streptococcus thermophilus, as well as trehalose and sorbitol as a cryoprotectant. The viable cell numbers of lactic acid bacteria in frozen yoghurt did not significantly decreased during six weeks frozen storage conditions. The MRS broth, which contains either trehalose or sorbitol, cultured with L. bulgaricus and/or S. thermophilus, and then the cultured medium was kept in the frozen condition for six weeks. The results indicated that lactic acid bacteria viability significantly increased with trehalose addition (2 and 5%) in the media compared to those of control and sorbitol supplement groups. The lactic acid bacteria viability in the yoghurts was examined on the effects of repeated freeze and thaw events. The freeze-thaw resistance of lactic acid bacteria significantly increased with trehalose supplement in the yoghurt. The major volatile aroma compounds (acetaldehyde, acetone, ethanol, diacetyl, and acetoin) in yoghurt were separated and indentified by headspace GC-FID analysis. Distinct flavor components and their ratios are known as important quality factors for yoghurt notes. Trehalose addition to the yoghurt was not influenced these factors during lactic acid fermentation. The results in this study demonstrated that trehalose potentially can be applicable as an effective cryoprotectant for lactic acid bacteria in the frozen yoghurt products.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.57-65
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• 2003

To investigate quality characteristics of kimchi prepared for the winter around Chonnam area, home made kimchi samples collected from 22 area, and they were stored at -1${\pm}$1$^{\circ}C$. The results were as follows : The pH and acidity of kimchi samples were 4.75 and 0.84%. respectively. Salt concentration was 3.50% and in Redox potential measurement, Eh value was -134.08mV. Ascorbic acid and reducing sugar contents were 10.l8mg% and 13.25mg%, respectively, In color measurement, L value was 52.29 and a and b values were 19.68 and 27.69, respectively. Total viable count was 5.5${\times}$10$\^$6/ and lactic acid bacteria count and yeast were 4.6${\times}$10$\^$5/ and 8.8${\times}$10$\^$5/. respectively. Properties of hardness of kimchi measured instrumentally was 9.26kgf. Alcohol insoluble solids(AIS) content was 5.53% and hot water soluble pectin(HWSP) content and sodium hexametaphosphate soluble pectin(NaSP) content were 17.35% and 29.65%, respectively, also hydrochloric acid soluble pectin(HClSP) content was 53.0%.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.550-556
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• 2022

The performance of enzymatic fuel cells that convert chemical energy contained in various organic molecules such as sugar, alcohol, organic acids, and amino acids into electrical energy is greatly affected by the cathode as well as the anode. This study aimed to develop a laccase-based cathode with high performance. An enzyme composite composed of an laccase, redox mediator, and carbon nanotubes was immobilized on the surface of electrode in multiple layers, and the effect of the number of layers and the presence or absence of carbon nanotubes on electrode performance was investigated. As the number of layers of the enzyme-mediator (Lac-(PVI-Os-dCl)) on the electrode surface increased, the amount of reduction current generated at the electrode increased. The enzyme-carbon nanotube-mediator composite electrode (Lac-SWCNTs-(PVI-Os-dCl)) generated a current 1.7 times greater than that of the Lac-(PVI-Os-dCl). It was found that the largest amount of current (10.1±0.1 µA) was generated in the electrode composed of two layers of Lac-(PVI-Os-dCl) and two layers of Lac-SWCNTs-(PVI-Os-dCl) in the evaluation of electrodes with different ratio of Lac-SWCNTs-(PVI-Os-dCl) and Lac-(PVI-Os-dCl). The maximum power density of the cell using the cathode composed of a single layer of Lac-(PVI-Os-dCl) and the cell using the optimized cathode were 0.46±0.05 and 1.23±0.04 µW/cm², respectively. In this study, it was demonstrated that the performance of cathode and the enzymatic fuel cell using the same can be improved by optimizing the layers of composites composed of laccase, redox mediator, and carbon nanotubes on the electrode surface.

• Journal of the Korean Society of Food Culture
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• v.22 no.6
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• pp.833-840
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• 2007

The purpose of this study was to obtain baseline data of nutritional management for women's bone health according to age. This study was conducted through questionnaire, bone mineral density(BMD) measurement by DEXA and dietary survey by 24hr recalls to 134 adult women. Subjects were divided into three groups: young women group who aged 20-29(n=48), middle aged women group who aged over 30 and were pre-menopause(n=36), postmenopausal women group(n=48). The body fat percent of postmenopausal women group was the highest among the three groups. BMD of lumbar spine(L1-L2) were $0.93\;g/cm^2$ for young women, $0.97\;g/cm^2$ for middle aged women, and $0.88\;g/cm^2$ for postmenopausal women, respectively(p<0.05). BMD of femoral neck(p<0.05), trochanter(p<0.05), and ward's (p<0.001) were significantly decreased as age increasement. Drinking alcohol and skipping meals were significantly higher in young women groups than in the other groups, however frequency of doing regular exercise was significantly lower in young women groups. Young women group consumed the significantly higher amount of cereals(p<0.05), sugar and sweeteners(p<0.001), meats(p<0.01), eggs(p<0.01), milks(p<0.05) and oils(p<0.001) than middle aged and postmenopausal women. Also, energy(p<0.001), animal protein, (p<0.01), plant oil(p<0.001), animal fat(p<0.001), retinol(p<0.001), vitamin E(p<0.01), and cholesterol(p<0.001) intakes of young women were highest among the three groups. However, young women group consumed the significantly lower amount of dietary fiber(p<0.05), vitamin C(p<0.01), folate(p<0.05) and fruits(p<0.01) than the other groups. To summarized the our results, young women who were in still undergoing bone formation activity to develope peak bone mass, had more dietary habit and lifestyle problems than middle aged and postmenopausal women. The results of this study revealed that nutritional management and education for bone health should be emphasized in young women not only aged women.

• Journal of Environmental Health Sciences
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• v.49 no.6
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• pp.289-294
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• 2023

Background: Artificial sweeteners are chemically synthesized substances used to add sweetness to foods. Representative substances include aspartame and acesulfame-K, which are 200 times sweeter than sugar. Recently, the IARC classified aspartame as class 2B, but Ministry of Food and Drug Safety of South Korea announced that it would maintain the current usage standards. Acesulfame-K, which has the potential to cause cancer, was excluded from the list of possible carcinogens, raising questions about its safety. According to a survey by the Consumers Union of Korea, 85% of makgeolli includes artificial sweeteners, but the content labelling is not indicated. It is necessary to accurately determine the intake of artificial sweeteners through makgeolli. Objectives: This study aims to evaluate the safety of makgeolli consumption by identifying the content of artificial sweeteners (aspartame, acesulfam-K) and preservatives (sorbic acid). Methods: Twenty makgeolli samples were purchased from large supermarkets and convenience stores by referring to the sales ranking of makgeolli products distributed in South Korea and the purchase ranking from online sites. The sample was sonicated to remove alcohol and carbon dioxide. Nine mL of acetonitrile was mixed with 1 mL of the prepared sample, centrifuged, and the supernatant was filtered and analyzed using HPLC. Results: As a result of the analysis, aspartame was detected in 17 products and acesulfame-K was detected in ten. The ADI of aspartame (40 mg/kg·bw/day) is higher than the EDI based on the maximum concentration 126.5 ㎍/mL. The ADI of acesulfame-K (15 mg/kg·bw/day) is higher than the EDI based on the highest concentration of 82.96 ㎍/mL. Although the health risk is low, IARC has raised the possibility of aspartame causing carcinogenesis, so there is a need to reevaluate the standards and regulations for artificial sweeteners. Conclusions: Through this study, we aimed to determine the content of aspartame and acesulfame-K contained in makgeolli currently distributed in South Korea and the safety of exposure to the human body when consumed.

• Food Science and Preservation
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• v.16 no.6
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• pp.991-998
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• 2009

We used pears to manufacture wine, and analyzed changes in pH, acidity and ethanol and sugar content during fermentation. Pear wine with added ginger (to improve quality) did not differ from ginger-free wine in pH or acidity level. The ethanol content of pear wine was the highest (13.0%, v/v) inpear wine with 0.1% (w/v) added ginger compared to pear wine with no ginger, and sensory tests examining taste and color yielded the highest scores for pear wine with 0.2% (w/v) ginger. To assess storage stability, pear wine was treated for 30 minutes at $55^{\circ}C$, $60^{\circ}C$, $65^{\circ}C$, or $70^{\circ}C$. Unheated pear wine showed rapid changes in pH and acidity level after 30 days of storage, whereas pear wine treated for 30 minutes at $60^{\circ}C$ did not show such changes. Total organic acid levels in pear wine increased by 0.71% and 0.89% (v/v), respectively. The free sugar level in pear wine decreased from 12.05% to 3.13% (w/v). Turning to phenolic compounds, caffeic acid, catechin, and epicatechin contents in pears were 1.64, 1.40, and 0.23 mg/100mL, respectively, with diverse compositions. Caffeic acid levels in pear wine decreased sharply to 0.12 mg/100 mL upon fermentation, whereas free catechin inpear wine increased to 1.16 mg/100 mL compared with 0.28 mg/100 mL in pears. Free arbutin increased from 8.34 mg/100 mL in pears to 10.39 mg/100 mL in pear wine. The free amino acid content of pear wine was 118.5 g/100 mL, but the levels of serine, alanine, glutamic acid, and aspartic acid decreased sharply upon fermentation, with corresponding increases in tyrosine, GABA, lysine, and arginine.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.305-311
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• 2017

This study aimed to evaluate the fermentation characteristics of mixed Makgeolli with barley and wheats under, fermentation at different temperatures (20, 25, and $30^{\circ}C$) and time (3, 6, and 9 days). The pH and sugar of mixed Makgeolli were 3.68~4.26 and $12.30{\sim}17.31^{\circ}Brix$, respectively. The total acidity showed proportionate increase with fermentation temperature and time; whereas, reducing sugar contents decreased with increasing fermentation temperature and time. The alcohol contents of mixed Makgeolli varied significantly by fermentation temperature and time (p<0.05). In terms of color values, the L value decreased with increasing fermentation temperatures, and a value increased significantly with increasing fermentation time. The number of microorganisms (yeast, total bacteria and lactic acid bacteria) in mixed Makgeolli decreased progressively with increasing fermentation temperature and time. Among the organic acids (citric, lactic, malic, and pyruvic acids) in mixed Makgeolli, citric and lactic acid was present at the highest concentrations. From these results, the optimum fermentation conditions of mixed Makgeolli with barley and wheat were $20{\sim}25^{\circ}C$ for 6 days.

• Applied Biological Chemistry
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• v.23 no.3
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• pp.157-165
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• 1980

Kojis were prepared from the different starch raw materials such as glutinous rice, barley rice, wheat flour and sweet potato, and were tested in an effort to reduce production cost and to improve quality of Kochuzang(red pepper paste). During the starting period of Koji preparation, there were less significant changes in pH; however, pH decreased somehow in the case of sweet potato, whereas it increased for the other Kojis. In general, the highest acidity was obtained after 72 hours of Koji preparation. Total nitrogen, soluble nitrogen and amino-nitrogen content increased in order of wheat flour, barley rice, and glutinous rice; Kojis they were markedly produced between 72 and 96 hours of Koji preparation. The maximum amount of reducing sugar was observed between 48 and 72 hours of Koji preparation during this period the reducing sugar content varied widely depending on starch source. Sweet potato Koji produced the highest level of ethyl alcohol content after 72 hours of Koji preparation; for the other Koji the same trends were observed after 24 hours. The starch liquefying activities have reached the highest level after 96 hours and for glutinous rice and barley rice; however, they kept on increasing until 120 hours for wheat flour and sweet potato. Koji Starch liquefying and saccharogenic amylase activities tended to increase in order of sweet potato, glutinous rice, barley rice and wheat flour. Kojis Various protease activities were measu-red during the Koji preparation, and they increased in order of alkali, neutral and acidic protease.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.366-370
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• 2007

Wild grapes contain various organic acids, vitamins, and inorganic salts compared to other various fruits. Their anthocyanin compounds are also known to have excellent effects in preventing cancers and heart diseases. Wild grapes are supposed to be a superior material for wine fermentation. This study was performed for searching optimum conditions for producing wild grape wines to improve their quality and taste. Four wild strains were isolated from Muscat Bailey A, ‘Kyoho’ grapevine, and wild grapes. For wild grape wine production, an optimum initial sugar concentration was $24^{\circ}Brix$ and an optimum temperature was $24^{\circ}C$. Sensory characteristics of the wild grape wine were evaluated for incense, sour taste, astringency, and sweet taste. Quality properties of the wild grape wine produced under the optimized fermentation conditions were analyzed. Total sugar, polyphenol contents, and acidity of the wild grape wine were 50.00 mg/mL, 25.30 mg/mL, and 0.95%, showing higher value than those of commercial grape wines. Amino acids, tannins, alcohol contents, and pH were 1.80 mg/mL, 1.88 mg/mL, 12%, and 3.59, respectively. The optimum fermentation conditions can be used to improve quality of the wild grape wine.