• Horticultural Science & Technology
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• v.35 no.4
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• pp.446-455
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• 2017

We investigated the physicochemical and sensory characteristics of oriental melon (Cucumis melo L.) to provide a consumer-oriented quality index. Oriental melon fruits were harvested at 20, 25, or 30 days after fruit set (DAFS), and each group was sorted by size (small, medium, and large). Fruits harvested at 25 and 30 DAFS had higher CIE $a^*$ and $b^*$ values, higher soluble solids content (SSC), and lower CIE $L^*$, firmness, and titratable acidity (TA) values than fruits harvested at 20 DAFS. Fruits harvested at 25 and 30 DAFS scored more highly for overall acceptance. A significant correlation was found between physicochemical characteristics and overall acceptance. In the delayed-harvest sample, increased sweetness and yellowness, and decreased sensorial texture were associated with an increase in overall acceptance. In principal component analysis, F1 and F2 explained 62.16% and 17.91% of the total variance (80.07%), respectively. Regression analysis of overall acceptance and F1 gave a coefficient of determination ($r^2$) of 0.87. Our results show that consideration of the physicochemical characteristics (CIE value, SSC, pH, SSC/TA ratio, and firmness) and sensory characteristics (yellowness, placenta area condition, oriental melon odor, sweetness, oriental melon flavor, texture, and off odor) of oriental melon in this way can be used as quality indices to predict consumer acceptance.

• Journal of Life Science
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• v.26 no.11
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• pp.1269-1274
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• 2016

The oyster is called "milk of sea" which is abundant in taurine, glycogen, cellenium. It could be used in making natural source. Recently, consumers have more interest in natural source because of their diverse preference and its special taste. The goal of this study is to optimize maillard reaction condition for manufacturing natural seasoning using oyster and oyster cooking drip hydrolysate. The result was judged by browning degree and pyrazine, which is flavor components when food heating. Hydrolysate and sugar react according primarily to type of sugar - glucose, xylose and fructose. Xylose was selected as best sugar of browning degree. In the case of sugar contents, all conditions over 1% of sugar contents are almost same. Therefore, the lowest 1% of sugar was selected as appropriate condition. According to the reaction with different temperature, browning degree and pyrazine contents had been increased over $60^{\circ}C$, but the product at $120^{\circ}C$had off-flavored. So, $100^{\circ}C$ is the best condition for the browning reaction. And in accordance with different reaction time, after 6 hours, there was no change in pyrazine and browning reaction. Therefore, to manufacture natural seasoning source, it is optimal to react xylose for maillard reaction at $100^{\circ}C$ for 6 hr with hydrolysate of oyster and oyster cooking drip.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.145-149
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• 1997

Lipoxygenase activity from brown rice varieties (Tongjinbyeo, Kumohbyeo and Kanchukbyeo) was investigated using spectrophotometric method. In all three varieties, there was an increase in the enzyme activity with the reaction time. Enzyme activity was tested at different concentration of the substrate. The $V_{max}\;and\;K_m$ values of Tongjin, Kumoh and Kanchukbyeo were 57.89, 19.85 and 31.38 units/mg protein and 0.054, 0.045 and 0.035 mM. The study of lipoxygenase activity at different pH levels showed that all the varieties had maximal activities around $pH\;7.0{\sim}7.6$. The enzyme activity and specific activity on milled fractions of different brown rice varieties, fraction II was superior to the other fractions and fraction IV was inferior to the other fractions. As the result of microwave heating for 0, 30, 60 and 90 sec, the enzyme activity and specific activity of all the varieties were decreased by the elapse of heating time.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.150-155
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• 1997

The twenty strains of Lactobacillus genus were tested for the optimal sponge fermentation of soda cracker. The six strains such as L. brevis, L. delbrueckii, L. fermentum, L. leichmanii, L. plantarum and L. sanfrancisco were selected because these strains did not smell off-flavor and showed the high value of TTA (total titrable acidity) after the fermentation. The selected strains consisted of the five strains of L. brevis, L. delbrueckii, L. fermentum, L. leichmanii and L. plantarum that mainly inhabited soda clacker and L. sanfrancisco that existed in San Francisco bread. The lactic acid bacteria were inoculated to the medium containing 10% wheat flour and then pH, TTA, acetic acid and lactic acid were measured during the sponge fermentation. The four strains of L. brevis, L. delbrueckii, L. fermentum and L. plantarum were used for the mixed lactic acid bacteria of sponge fermentation because the TTAs of L. brevis, L. fermentum and L. plantarum were higher than those of other lactic acid bacteria and L. delbrueckii rapidly produced organic acids and a large amount of acetic acid. Among the combination of L. brevis, L. fermentum, L. delbrueckii and L. plantarum, the mixed lactic acid bacteria of L. brevis, L. fermentum and L. plantarum showed the highest TTA, the lowest pH and the largest amount of acetic acid. Therefore, the mixed lactic acid bacteria of L. brevis, L. fermentum and L. plantarum were used for optimal sponge fermentation of soda cracker.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.353-360
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• 1992

This study was carried out to investigate the changes of quality in yogurt during delivery and storage. To do this, microbiological, physico-chemical and sensory properties in stirred yogurt were studied at different temperatures $(10^{\circ}C$ & $20^{\circ}C)$ and shakings (100 rpm & 200 rpm for 30 min). Titratable acidity and TCA soluble nitrogen in yogurt were increased in accordance with increase of temperature and time, while pH, lactose and lactic acid bacteria tended to be decreased. Interestingly enough, shaking conditions almost did not influence these studies. In sensory evaluation it showed that acidity was strong and sweetness was weak as increasing the storage temperature and time, but there were no significant differences until 10 days at $10^{\circ}C$ and 3 days at $20^{\circ}C$. Off-flavor was developed after 12 days at $10^{\circ}C$ with only 200 rpm shaking and after 6 days at $20^{\circ}C$ in both shaking conditions. These yogurts were not suitable for consumer. Viscosity in the yogurt became high as the temperature and time were increased. Viscosity was lower in yogurt shaked at 200 rpm than in non-shaked yogurt. Finally, this study indicates that temperature and shaking during delivery of yogurt may be critical in keeping quality of yogurt.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.806-813
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• 2000

Attempts were made to evaluate possibilities of adding water soluble chitosan to milk for improving functionality of milk, and physico-chemical and sensory properties of chitosan added milk were studied. pH and acidity of milk with ethyl alcohol washed chitosan were close to those of control. Color and consistency of chitosan added milk were better with chitosan of lower molecular weight than with high molecular weight. Chitosan of high molecular weight resulted in increased consistency and browning of milk. Milk with less than 1.0% chitosan could be sterilized at $73^{\circ}C$ for 15 sec. with minimum protein coagulation and increase of consistency. Low molecular weight chitosan$(MW\;0.2{\sim}3\;kDa)$ accelerated the growth of Bifidobacterium bifidum, showing 10 times more cell population after 32 hrs incubation. Sensory tests showed that adding chitosan to the regular city milk resulted in significant difference in color and chemical off-flavor(p<0.05). When chitosan was added to coffee milk, there was no significant difference in sensory quality from control. The storage test showed that pH, acidity, consistency and color of coffee milk with 0.5% chitosan did not change markedly during 30 days storage at 0 and $5^{\circ}C$, but changed rapidly after 16days storage at $10^{\circ}C$. Bacterial counts increased when storage temperature was high, and the growth of bacteria was delayed in coffee milk with chitosan.

• Food Science and Preservation
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• v.19 no.1
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• pp.7-11
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• 2012

This study was conducted to determine the effects of the humidity and gas composition on the quality of satsuma mandarins during their heat treatment, in an effort to reduce their acidity. To come up with different humidity and gas conditions, various plastic films were used. The fruits were wrapped with an 18-${\mu}m$ high-density polyethylene (HDPE) punched film, a 30-${\mu}m$ low-density polyethylene (LDPE) film, or a 100-${\mu}m$ LDPE film just before treatment at $30^{\circ}C$ for 55 hours. After heat treatment, the titratible acidity (TA) was significantly reduced while the soluble-solid content (SSC) showed no differences, which resulted in increased SSC/TA ratios in all the treatments. The fruits that were not wrapped with a film, however, which had low RH, developed higher ethanol and acetaldehyde contents than those wrapped with an 18-${\mu}m$ HDPE punched film, which had high RH and a similar gas composition. Among the films, the higher the $CO_2$ concentration in the film was, the more the ethanol and acetaldehyde contents increased, which induced more off-flavor. It was thus concluded that high humidity and normal gas composition are favorable conditions for heat treatment to reduce the acidity of satsuma mandarins.

• Journal of Environmental Science International
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• v.26 no.8
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• pp.967-976
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• 2017

In this study, the effect of probiotic supplementation on growth performance, blood metabolites, and meat quality of Hanwoo steer was investigated. A total of 32 Hanwoo steers (15-17 months, average body weight $462{\pm}37.9kg$) were randomly allotted to 4 dietary treatments (0, 0.5, 1.0, and 1.5% mixed probiotics), with four Hanwoo steers per pen (two replicates per treatments), and reared for 12 months. There were no differences among treatments in growth performance of Hanwoo steer (P>0.05); however, feed intake decreased linearly with increasing levels of mixed probiotics. Growth hormone and Blood Urea Nitrogen (BUN) levels responded linearly with increasing levels of dietary mixed probiotics (P<0.05), but not insulin and blood glucose did not. In particular, total cholesterol was significantly lower for the 1% mixed probiotic treatment in comparison with that of the other treatments (P<0.05). The pH, Thiobarbituric Acid Reactive Substances (TBARS), cooking loss, and meat color were influenced by increasing levels of mixed probiotics (P<0.05), but the carcass characteristics and shear force were not. Regarding sensory evaluation, the addition of mixed probiotics resulted in significant difference in meat color, tenderness, aroma, off-flavor, juiciness, and marbling score, but not in overall acceptability. In addition, fatty acid profiles indicated no differences between control and mixed probiotic treatments. In conclusion, mixed probiotic treatment at 1% levels can enhance consumer preferences possibly by reducing cholesterol and TBARS.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.415-419
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• 2007

This study was conducted to compare the storability of some sprout vegetables; alfalfa, broccoli, radish, red-cabbage, and red-radish, packed with 50 low density polyethylene (LDPE) film in MA storage. Most of all 5 different sprout vegetable crops maintained the fresh weight higher than 99% until 10 days storage at 2 and $8^{\circ}C$. The carbon dioxide concentration in packages was higher at 8 than at $2^{\circ}C$. It was higher in radish and red-radish sprouts than other crops. As the oxygen concentration showed opposite trends to carbon dioxide, that of radish and red-radish sprouts decreased more than 3% after 3 days in 8 storage. Ethylene concentration in the packages of alfalfa was 0.1 ppm, significantly higher than other four crops with less than 1.0 ppm. Temperature treatment, however, did not influence the ethylene concentration in packages. The radish and red-radish sprouts, with lowest oxygen concentration in package, showed lowest off-flavor compared to the others. The visual quality of these sprouts in packages showed higher at $2^{\circ}C\;than\;at\;8^{\circ}C$ and was maintained the highest in radish sprouts, followed by red-radish, broccoli, red-cabbage, and alfalfa sprouts in that order. In conclusion, as the sprout vegetables have different shelf-life, of which radish was $4{\sim}5$ days longer than that of alfalfa the distributed condition of sprout vegetables should be differently controlled according to kinds of crops.

• Korean journal of food and cookery science
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• v.14 no.2
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• pp.201-206
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• 1998

This study was conducted to determine the changes in the contents of vitamin C and reducing sugars of wheat flour and glutinous rice pastes added Kimchi during fermentation. Kimchi was fermented at 10$^{\circ}C$ for 14 days. Sensory evaluation of various Kimchi samples were also conducted. During fermentation, pH decreased in the order of wheat flour paste added Kimchi (WHFP-Kimchi), glutinous rice paste added Kimchi (GLRP-Kimchi) and control. Total acidity increased in the same order The contents of total vitamin C of all Kimchi samples decreased. Total reducing sugar contents of Kimchi juices from various samples decreased in the order of WHFP-Kimchi, GLRP-Kimchi and control. In sensory evaluation, the red color of Kimchi juice decreased in the order of control>WHFP-Kimchi>GLRP-Kimchi. Off flavor decreased control>WHFP-Kimchi>GLRP-Kimchi. Firmness decreased control> GLRP-Kimchi>WHFP-Kimchi. Sour tate decreased WHFP-Kimchi>Control>GLRP-Kimchi. But there were no significant difference in crispiness, ans salty taste. Overall prefernce decreased GLRP-Kimchi>control>WHFP-Kimchi.