• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.179-184
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• 1998

As a way of mass process of onion, Allium cepa L., the oleoresin decompressed and concentrated is an alternative process to minimize lowering in the quality of onion during storage, to improve the original flavor and taste, and to increase variety as processing aids. This study was performed to investigate on the quality stability during storage of oleoresin. Oleoresin product was manufactured by mixing a concentration of onion juice and ethanol extract homogenously, emulsified by an additional 2% PGDR(polyglycerol condensed ricinoleate) and 1% cysteine. During 60 days storage at 5$^{\circ}C$, $25^{\circ}C$ and 4$0^{\circ}C$ the total sugar content in oleoresin product was very stable, and absorbances at 420nm as browning reaction index were 0.38, 1.53 and 3.32, respectively, addition of 1% cysteine retarded the browning reaction effectively. When oleoresin product was centrifuged(2000$\times$G, 60 minutes), the volumes of emulsion level without separation were 96.8%, 94.1% and 9.06%, respectively during 20 days, 40 days and 60 days storage at 5$^{\circ}C$, and those during 60 days storage at $25^{\circ}C$ and 4$0^{\circ}C$ were appeared to be 83.2% and 75.4%. Showing lower level as increasing storage temperature. Antioxidant indexes(AI) of soybean oil added 1% oleoresin without storage and 0.02% BHA were 1.39 and 1.72. The former showed 80.8% antioxidant activity on induction time extension effect of the latter. Antioxidant indexes of oleoresin decreased slightly as increasing storage temperature and were 1.37, 1.30 and 1.08. Total pyruvate contents were 89.9%, 79.7% and 65.2%, respectively during 60 days storage at 5$^{\circ}C$, $25^{\circ}C$ and 4$0^{\circ}C$. Rate constant, Q10 value and activation energy were 1.381~4.735 mmol/$\ell$.hr, 1.537~1.694 and 11.649 ㎉/g mole for the reduction of pyruvates in the range of storage temperatures during oleoresin storage.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.171-178
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• 2013

In this study, the sludge that occurs in the initial operation of coagulation system developed for the treatment of CSOs were returned to the flocculation reactor. The purposes of this study were to analyze the Characteristics of flocs that are generated through the recycling sludge and settling characteristics of sludge, and to evaluate the possibility that high concentrations of particulate matter in the initial inflow of CSOs could be used as an weighted coagulant additive. As a result, the concentration of treated CSOs pollutants at the beginning of the CSOs influent with a large amount of particulate matter over 20 ${\mu}m$ was low, after gradually increasing the concentrations of them. The flocs generated from the sludge return were similar in size compared to flocs generated through injection of micro sands, and settling velocity in case of return sludge injection was decreased from 55.1 cm/min to 21.5 cm/min. SVI value of the sludge accumulated at the bottom of the sedimentation tank was 72, and settled sludge volume decreased rapidly due to the consolidation of sludge to the time it takes to 10 minutes. these mean that sludge used for recycling has good settling characteristic. A condition of returned sludge which is 0.1% return of 0.3% extraction was formed in the balance of settlement and extraction. In this case, This condition was to be adequate to maintain the proper concentration such as 100~200 mg/L of TS and 50~100 mg/L of VS in the flocculation reactor. The usage of the return sludge containing particulate matters of CSOs as an weighted coagulant additive was able to secure a stable treated water quality despite the change of influent water quality dynamically. Furthermore, it can be expected to reduce the alum dosage along with the sludge production.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.217-225
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• 2004

This study was carried out to reduce the loss of frozen dough quality during frozen storage. Using response surface method, ascorbic acid 160.4 ppm, L-cysteine 63.1 ppm, and SSL 0.6% were found to be optimum, with xanthan gum 0.3% (formula A) and Ultra tex-3 5% (formula B) added as cryoprotectants. During frozen storage at $-20^{\circ}C$, control rapidly deteriorated after 4 weeks, while formulas A and B showed slight deterioration with immutable quality after 10 weeks.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.426-438
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• 2023

Lithium-sulfur batteries, recently attracting attention as next-generation batteries, have high energy density but are limited in application due to sulfur's insulating properties, shuttle phenomenon, and volume expansion. This study used an economical and simple vacuum filtration method to prepare a freestanding electrode without a binder and collector. Carbon nanotubes (CNTs) are used to improve the electrical conductivity of sulfur, where CNT also acts as both collector and conductor. In addition, metal oxides (MO_x, M=Ni, Mg), which are easy to adsorb lithium polysulfide, are added to the CNT/S electrode to suppress the shuttle reaction in lithium-sulfur batteries, which is a result of suppressing the loss of active sulfur material due to the excellent adsorption of lithium polysulfide by metal oxides. The MO_x@CNT/S electrode exhibited higher capacity characteristics and cycle stability than the CNT/S electrode without metal oxides. Among the MO_x@CNT/S electrodes, the NiO@CNT/S electrode displayed a high discharge capacity of 780 mAh g^-1 at 1 C and an extreme capacity decrease to 134 mAh g^-1 after 200 cycles. Although the MgO@CNT/S electrode exhibited a low discharge rate of 544 mAh g^-1 in the initial cycle, it showed good cycle stability with 90% of capacity retention up to 200 cycles. Further, to achieve high capacity and cycle stability, the Ni_0.7Mg_0.3O@CNT/S electrode, mixed with Ni:Mg in the ratio of 0.7:0.3, manifested an initial discharge rate of 755 mAh g^-1 (1 C) and a capacity retention rate of more than 90% after 200 cycles. Therefore, applying binary metal oxides to CNT/S provides a freestanding electrode for developing economical and high-performance Li-S batteries, effectively improving lithium polysulfide's high capacity characteristics and dissolution.