• Food Engineering Progress
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• v.21 no.1
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• pp.49-56
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• 2017

Vegetable seed oils (VSOs) have been extracted and used not only as ingredients in food and as sources of dietary lipids, but also as sources of nutraceuticals used to overcome the various oxidative stresses that contribute to the development of diseases, including cancer and other chronic conditions. The chemical compositions and oxidative stabilities of various VSOs were therefore investigated; samples were stored for 35 d, with each oil having been tested under $O_2$ exposure, sealed from $O_2$ exposure and sealed from $O_2$ exposure while containing $O_2$ scavengers. Oxidative stability was evaluated by peroxide value (POV), p-anisidine value (p-AnV), iodine value (IV), and thiobarbituric acid (TBA) value. Perilla seed and flaxseed oil were mostly composed of linolenic acid (45.5% and 59.7%, respectively), whereas pine seed oil was mostly composed of linoleic acid (48.3%). Meanwhile, camellia seed and olive oils contained 80% oleic acid, which correlated strongly with oxidative stability. The POV, p-AnV, and TBA values were the highest under $O_2$ exposure, and the lowest in the presence of $O_2$ scavengers. These results indicate that VOS oxidative stability depends not only on storage conditions, but on unsaturated fatty acid profiles as well.

• Korean journal of food and cookery science
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• v.32 no.3
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• pp.253-260
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• 2016

Purpose: To develop fat-free dressing containing a resistant starch (RS) as a dietary fiber, the viscosity and stability of various type RSes prepared from wheat, maize, potato, rice, waxy rice, and amaranth starches were investigated by using Brookfield viscometer. The shape of RS granule in the dressing during storage was also observed. Methods: The viscosity of fat free dressing with different retrograded RS3 (RS3V) prepared from waxy rice starch with 0.1% lemon vinegar and ascorbate mixed solution had higher RS3 that was maintained constant during storage. Annealing and heating prior to cross-linking, and heating after cross-linking increased RS level of RS4 type starches. Results: The viscosities and stabilities of dressings with RS were different depending on starch sources and RS preparation conditions. The heated RS4 (HRS4) increased in viscosity and stability with RS4 addition. Especially the fat-free dressings with HRS4 prepared from rice and waxy rice starches maintained stability regardless of separation after one month storage with only 7% separation after 6 month storages. The shape of RS4 granule in acidic medium of dressing did not change until 6 months. Conclusion: In this study, RS4 made by the rice and waxy rice starches showed high viscosity and maintained stability of the fat-free dressings during storage.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.833-839
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• 1990

To examine the effects of nitrogen flushing on the storage stability of red pepper powders, the color and capsanthin and capsaicin contents were investigated. Capsanthin and capsaicin contents of red pepper powders during their storage decreased as the increase of temperature. Nitrogen flushing packaging was good for the retention of capsanthin and capsaicin than air packaging. Brown color of red pepper powders during their storage differed with storage temperature and packaging condition, thus low temperature and nitrogen reduced the brown color substantially, L and b values by Hunter's color were almost not changed during 10 months storage of red pepper powders, and a value was decreased as the increase of temperature. Therefore, nitrogen flushing packaging for the storage of red pepper powders was good than air packaging.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.1076-1081
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• 1999

Physicochemical, microbiological, and sensory properties of barleys irradiated by gamma ray at 1.2kGy, 10.1kGy, or 30.5kGy were investigated every 40 days during the storage at 25℃ and 50% relative humidity. Moisture content of the irradiated barleys decreased but crude lipid content increased during the storage. TBA values increased in proportion to the irradiation dose and to the storage period. In Hunter's color, L, a, and b values of 30.5kGy dose irradiated barleys were higher than those of the non irradiated barleys right after irradiation and this trend continued during the storage. Numbers of mesophilic and psychrophilic bacteria in the non irradiated barleys and 1.2kGy dose irradiated barleys were higher than those in the barleys irradiated at 10.1kGy and 30.5kGy during the storage. Numbers of yeasts and molds in the irradiated and non irradiated barleys were low and they did not greatly increase during the storage. In sensory evaluation, acidic odor of the barleys was strong at the 10.1kGy and 30.5 kGy dose irradiation but barley odor and humid odor were not significantly different among the groups depending upon the radiation dose and storage period.

• Journal of Life Science
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• v.25 no.10
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• pp.1124-1131
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• 2015

Consumer interest in the stability of medicinal herb extracts during storage has increased. Although the advent of new technologies has improved preservation conditions, increasing the storage time, there are few studies on the preservation of herb extracts. The purpose of this study was to perform microscopic observations of Samul-tang decoctions under various preservation conditions. The storage temperature (a high temperature, room temperature, with or without light, refrigeration, or cryopreservation) and storage time (0, 15, 30, 90, and 180 days) were given to each condition Macroscopic morphology, pH, UV absorption, HPLC, and bacteriological studies were performed to determine microscopic changes in Samul-tang decoctions. The biological activity (tyrosinase inhibition) of the Samul-tang decoctions was also examined. There were no major changes in the indicated observation items when the extracts were stored in each condition. However, at higher storage temperatures and longer storage times, microscopic changes increased, although no bacteria were detected. Furthermore, the higher the storage temperature was and the longer the storage time was, the bigger the change was, despite of minor microscopic changes. Therefore, to maintain the stability of herbal extracts during storage, it is recommended to keep the Samul-tang decoction in the preservation condition of refrigeration and cryopreservation or without light rather than high temperature and room temperature as possible.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2254-2261
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• 2018

This paper analyzes stability of current control in respect of four cases of battery energy storage system (BESS) in a stand-alone microgrid. The stand-alone microgrid is composed of BESS, diesel generator and controllable loads, where all of them have a rated power of 50kW. The four cases are considered as following: 1) BESS with a stiff grid 2) BESS with the diesel generator 3) BESS with passive damping + diesel generator 4) BESS with active damping + diesel generator, and their stabilities are analyzed in the frequency domain and discrete time domain. The comparative analysis for four cases are verified through simulation and experiments through demonstration site of the stand-alone microgrid, where the DC link is connected to a 115kW battery bank composed of 48 lead-acid batteries (400AH/12V). Experimental results show a good agreement with the analysis.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.1-7
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• 2008

Superconducting Magnetic Energy Storage (SMES) can inject or absorb real and reactive power to or from a power system at a very fast rate on a repetitive basis. These characteristics make the application of SMES ideal for transmission grid control and stability enhancement. The purpose of this paper is to introduce the SMES model and scheme to control the active and reactive power through the power electronic device. Furthermore, an optimal priority scheme is proposed for the combination of active and reactive power control to be able to stabilize power transient swings.

• Culinary science and hospitality research
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• v.24 no.2
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• pp.79-86
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• 2018

The purpose of current study was to evaluate the oxidative stability of soybean oil after frying according to storage temperature. The soybean oil after 10 times deep fat frying with potato sticks (10% w/w of oil) were stored during 10 days at 30, 60 and $90^{\circ}C$ and chemical properties were determined. The acid value and peroxide value were the highest and the iodine value were the lowest when the oil stored at $90^{\circ}C$. Expecially, the production rate of peroxide was fast at over $60^{\circ}C$. According to the results, frying oil should not be stored for more than 6 days at $30^{\circ}C$ after use. Since the oil used had already produced unstable peroxides, oxidation could proceed relatively quickly even at low temperatures. Therefore, it is desirable to keep the used oil at a temperature as low as possible.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.8
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• pp.841-849
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• 1992

In power system operation, the stability of synchronous machine has been recognized one of the most important things. AESOPS program developed by EPRI in U.S.A. is a frequency domain analysis program in power system stability and it computes the electro-mechanical oscillation mode. This paper presents how to analyze the power system small signal stability problem efficiently by uusing the AESOPS program and analyze the various factors affecting the damping characteristics of these oscillations in KEPCO power system of 1986 with pumped-storage plant. To reduce the computing time and efforts, selecting the poorly-damped oscillation mode and clustering technique have been used. The characteristics of load, the amount of power flow on the transmission line and the gain of exciter have a significant effects on the damping of the system while the governing system has only a minor one. With the Power System Stabilizers, the stability of the power system has been improved.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.547-555
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• 2021

A catalyst-plasma reactor was applied to the storage of agricultural products, e.g., apple and kiwi, to remove the ethylene generated during the storage. Two 1-m³ unit containers were prepared, and the long-term storage stability of the control group at room temperature was compared with that of the experimental group of which the produced ethylene was treated by the catalyst-plasma reactor. In case of the experimental group, a small amount of ozone was injected to the unit container to suppress the growth of microorganisms such as mold. The apples and kiwis were stored at room temperature for 50 and 57 days, respectively, and the changes in ethylene concentration, hardness, sugar content, acidity, and loss rate were compared. The ethylene concentration during the storage for the control group was higher than that for the experimental group, indicating that the ethylene was effectively removed. Hardness, sugar content, and sugar acid ratio after the storage were better than before the storage, and in particular, the storage stability of kiwifruit was improved significantly. In addition, after the storage, the loss rates of apples and kiwis in the control group were 10 and 54.1%, respectively, but the loss rates in the experimental group were 6 and 34.8%, respectively. Therefore, the storage stability of the experimental group was a lot better than that of the control group.