• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1819-1825
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• 2015

This study was carried out to investigate the effect of hydrocolloids [hydroxypropylmethyl cellulose (HPMC), xanthan gum (XG), guar gum (GG), and glucomannan (GM)] on the physicochemical properties of bread flour dough containing rice flour. In amylograph analysis, the significantly lowest gelatinization temperature was obtained in dough with XG (P<0.05). XG revealed the highest maximum viscosity while GM revealed the lowest. In viscograph test, the lowest gelatinization temperature and maximum viscosity showed the same result as in the amylograph. Breakdown value was also highest in dough containing XG, but lowest in the control and dough containing HPMC. Setback value was highest in dough containing HPMC, but lowest in dough containing XG. In farinograph analysis, consistency was greatest in dough with HPMC and XG. Hydrocolloids affected water absorption, which was highest in dough containing GM. Development times of dough containing HPMC and XG were low. Stability was lowest in dough with XG. Degree of softening was reduced in dough containing HPMC and GG compared to the control but increased in dough containing XG and GM. Dough containing HPMC and GG showed the largest volume at 3 h of fermentation. Dough with HPMC showed the lowest pH value. Hydrocolloids in this study affected physicochemical properties of dough.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.515-521
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• 2000

The effect of precipitates on the high temperature tensile properties of cast alloy 718 was investigated by phase extraction method and microstructural observation. The value of tensile strength and elongation gradually decreased with increasing testing temperature up to $760^{\circ}C$. Elongation of the alloy increased, while tensile strength decreased above 76$0^{\circ}C$. The amount of precipitates in the specimen that tensile tested at $760^{\circ}C$ showed maximum owing to stress assisted precipitation. Therefore, the alloy exhibited the lowest value of the elongation and the degree of decrease in yield strength at this temperature due to high flow stress of precipitates. Little amount of precipitate, especially $\gamma$' and $\gamma$＂, resulted in softening of the alloy at the temperature above $760^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.341-346
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• 2014

This study was conducted to evaluate the effect of trehalose on the rheological properties of bread flour dough. Farinographic and viscographic properties, pH, total titratable acidity (TTA), and fermentation power were analyzed for flour dough rheology. Flour dough containing trehalose showed greater water absorption capacity and longer development time. However the stability, degree of softening, and farinograph quality number (FQN) were lower for the trehalose-containing flour dough, however, these factors decreased with increasing amounts of trehalose. Trehalose did not affect the beginning of gelatinization temperature and maximum viscosity temperature of flour. The maximum viscosity was the lowest with 6% trehalose, the end of final holding period, breakdown and setback values decreased with increasing amounts of trehalose. Flour dough with 4% trehalose had the lowest pH value for 120 min fermentation at $30^{\circ}C$, and the highest TTA value. Addition of 4% and 6% trehalose showed larger fermentation volume of dough than the control. The results suggested that trehalose positively affected the rheological properties of flour dough such as bread volume, softness, and staling delay.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1036-1042
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• 2002

During storage at $25^{\circ}C$, the effect of gas absorbents, such as carbon dioxide scavenger, ethylene absorber, and their combinations, on respiration characteristics and quality attributes of mature-green Mume fruits packaged in $30\;{\mu}m$ low density polyethylene (LDPE) film was examined. Changes in quality attributes of the fruits were observed in terms of weight loss, titratable acidity, pH, fish firmness, color, water-soluble solid, and chlorophyll contents. In the presence of ethylene absorber $(KMnO_4)$, the physiological injury was remarkably suppressed, and there was no significant injury in Mume fruits at $25^{\circ}C$ for 10 days. Yellowing and softening were also noticeably reduced by the combination of plastic film packaging and inclusion of ethylene absorber. The respiration rate was slower in fruits sealed with ethylene absorber than in those with absorbent-free packaging. Using ethylene absorber, levels of oxygen and carbon dioxide were maintained at 2-3 and 7-8%, respectively, during storage at $25^{\circ}C$ for 10 days. The addition of carbon dioxide scavenger $(Ca(OH)_2)$, negatively affected the quality attributes and respiration characteristics of the fruits. Overall results showed that ethylene removal by gas absorbent in the film packages significantly prolonged the shelf life of the fruits at ambient temperature.

• Food Science and Preservation
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• v.23 no.1
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• pp.12-19
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• 2016

This study was conducted to determine $CO_2$ treatment condition to extend the shelf-life of 'Seolhyang' strawberry. Fresh strawberries with red color on 80% of the fruit surface were harvested. The samples at two different stages (on the $1^{st}$ and $3^{rd}$ day after harvest) were placed in a gas-tight chamber with 0, 5, 15, or 30% $CO_2$ concentration for 3 hours at $4^{\circ}C$. Then, the strawberry samples were immediately packaged in a PET tray and stored at $4^{\circ}C$. The carbon dioxide treatment was effective in maintaining the quality of 'Seolhyang' strawberries treated on the $1^{st}$ day after harvest. These samples had higher firmness, lower redness, softening index, and decay rate compared to samples treated on the $3^{rd}$ day after harvest. Treatment with both 15 and 30% of $CO_2$ concentration on the $1^{st}$ day after harvest induced an increase of firmness of 'Seolhyang' strawberry after the treatment. Samples treated with 15 and 30% $CO_2$ the $1^{st}$ day after harvest maintained quality for 10 days. However, samples treated with $CO_2$ on the $3^{rd}$ day after harvest lost marketability at 10 days of storage. At the atmosphere containing 30% $CO_2$ on the $1^{st}$ day after harvest was most effective in reducing decay rate and fruit softening, and maintaining bright red color of strawberries among different $CO_2$ concentrations. Therefore, a 30% $CO_2$ treatment within one day after harvest can be a practical postharvest technology to extend shelf-life of 'Seolhyang' strawberry.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.31-39
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• 2021

In this study, the fiber blending ratio and strain rate effect on the tensile properties synergy effect of hybrid fiber reinforced cement composite was evaluated. Hooked steel fiber(HSF) and smooth steel fiber(SSF) were used for reinforcing fiber. The fiber blending ratio of HSF+SSF were 1.5+0.5, 1.0+1.0 and 0.5+1.5vol.%. As a results, in the cement composite(HSF2.0) reinforced with HSF, as the strain rate increases, the tensile stress sharply decreased after the peak stress because of the decrease in the number of straightened pull-out fibers by increase of micro cracks in the matrix around HSF. When 0.5 vol.% of SSF was mixed, the micro cracks was effectively controlled at the static rate, but it was not effective in controlling micro cracks and improving the pull-out resistance of HSF at the high rate. On the other hand, the specimen(HSF1.0SSF1.0) in which 1.0vol.% HSF and 1.0vol.% SSF were mixed, each fibers controls against micro and macro cracks, and SSF improves the pull-out resistance of HSF effectively. Thus, the fiber blending effect of the strain capacity and energy absorption capacity was significantly increased at the high rate, and it showed the highest dynamic increase factor of the tensile strength, strain capacity and peak toughness. On the other hand, the incorporation of 1.5 vol.% SSF increases the number of fibers in the matrix and improves the pull-out resistance of HSF, resulting in the highest fiber blending effect of tensile strength and softening toughness. But as a low volume fraction of HSF which controlling macro crack, it was not effective for synergy of strain capacity and peak toughness.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.42-49
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• 2012

This experiment was conducted to find out the effects of nitrous oxide ($N_2O$) on the postharvest quality of 'Janghowon hwangdo' peach fruits. Fruits were harvested at commercial maturity for marketing in late September, and treated with 70% $N_2O$ + 20% $O_2$ + 10% air, 80% $N_2O$ + 20% $O_2$, and 90% $N_2O$ + 10% $O_2$ for 48 h, and then stored at $15^{\circ}C$. No significant treatments for soluble sugar and titratable acidity contents were detected. However, good appearance and taste in peach fruit were maintained better in 80% $N_2O$ treatment than in air treatment. The treatment with 90% $N_2O$ had negative effects on weight loss and taste because of rotting by anaerobic fermentation. 80% $N_2O$ treated fruit had significantly higher fungus (Botrytis cinerea) growth inhibition of saprogenic approximately than air treatment until 12 days of storage. The browning and rotting at surface of peach were also retarded when peaches were treated with 80% $N_2O$ before they were artificially wounded. The activity of polyphenol oxidase (PPO) was inhibited about 80% in peach of 80% $N_2O$ treatment compared with in air treatment. The result showed that 80% $N_2O$ treatment was able to extend the shelf life of peach fruits through maintaining taste and inhibition of softening and browning by rotting and wounding during storage.

• Food Science and Preservation
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• v.20 no.6
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• pp.766-774
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• 2013

The effect of storage temperatures ($0^{\circ}C$and $20^{\circ}C$) and packing functional film for fruit quality were examined in 'Fuyu' persimmon. The fresh weight loss was delay more effectively by the inhibition of transpiration when functional film was used. The firmness was effectively maintained in functional film packages at low temperature ($0^{\circ}C$), which might result from the beneficial combination of $CO_2$ and $O_2$. The soluble solid contents was higher with packing of functional film at $0^{\circ}C$ than at room temperature ($20^{\circ}C$). Highest $CO_2$ production in functional film bags was observed in room temperature storage after one week and thereafter declined sharply whereas lowest in 8 weeks. $CO_2$ concentration regardless of packing slowly increased to $5.2{\mu}L{\sim}10.2mL{\cdot}kg^{-1}{\cdot}h^{-1}$ until 8 weeks of low temperature due to persimmon respiration. Hunter 'b' value changed greatly yellowness according to temperature of storage but there were no significant differences among packaging treatments. Effects of functional film and low temperature in slower softening were consistent. This results suggested that the packing functional film at low temperature resulted in the best retention of quality market.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.376-381
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• 1992

In order to study the effect of modified atmosphere storage on extending shelf life of mushrooms, oyster mushroom and Shiitake were wrapped with polyethylene film (PE, $50\;{\mu}m$), and stored at $0.5^{\circ}C$. Mushrooms packed with conventional hardboard box (4kg) lost marketability within $5{\sim}6$ days due to weight loss, shrinkage, browning, spore formation and/or mycellium growth. PE-packing could prevent or retard the deterioration of the mushrooms in the aspects of appearance, texture, discoloration, and microbial contamination. This situation can be best characterized by the reduced respiration rate resulted from the elevated level of carbon dioxide and the reduced level of oxygen in the bag. Although the appearance of the oyster mushroom was maintained for one month, its shelf life was limited to 15 days because of tissue softening. Discoloration of the pileus of shiitake mushroom appears to be the most important factor to determine its marketability. For example, extension of shelf life of Dongo was limited to 15 days, principally due to the browning of the pileus. Shelf life of Hawgo whose color of the pileus changed little over the experimental period, however, could be extened to more than one month.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.11 no.2
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• pp.81-85
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• 2005

The mature-red tomato fruits (cv. Pinky world) were packaged with functional modified atmosphere (MA) film (0.03, 0.06 mm) and stored at 0, 5, $15^{\circ}C$. The results showed that the concentrations of $CO_2$ and $O_2$ inside MA package were about $4.21{\sim}8.17%$ and $9.78{\sim}14.45%$ under steady state during storage 29 days at 0, $5^{\circ}C$, respectively. The MA packaging(MAP) suppressed the fruits softening and the color change. The minimum lycopene content and maximum firmness were separately observed in fruits packaged with MA film (0.03 mm) at $5^{\circ}C$ storage and film(0.06 mm) at $0^{\circ}C$, which the lycopene content 6.08 mg/100 g, and firmness was 0.49 Kgf at 29 th day storage. The optimal conditions to keep high quality of tomato fruits were obtained by MAP during storage at $0^{\circ}C$ for 29 days, independently of the film thickness, in which the adequate gas composition was $CO_2$ at $4.2%{\sim}5.6%$, $O_2$ at $14.3%{\sim}14.5%$, respectively.