• Applied Biological Chemistry
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• v.36 no.4
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• pp.284-289
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• 1993

The effect of oil refining processes-degumming, alkali-refining, bleaching and deodorizing-on oil characteristics and oxidation stability of sesame oil were investigated. The colors(L, a, b) of samples were markedly changed and their peroxide and acid values were decreased, while the other characteristics of samples were not changed during refining stages. The L values of alkali-refined, bleached and deodorized sesame oils were largely decreased and their a values were increased due to browning reaction during the storage at $70^{\circ}C$. The colors of crude and degmmed sesame oils were very stable and their peroxide, free fatty acid and conjugated dienoic acid values were slowly increased. Volatile carbonyl compounds formed by oxidation were increased during the storage at $70^{\circ}C$. The results indicated that refining processes did not affect the sesame oil characteristics but decreased the oxidation stability of sesame oil.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.4 s.34
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• pp.65-74
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• 1999

We have studied the stability of W/O high internal phase emulsions(HIPE) containing water, cetyl dimethicone copolyol and oils varying magnesium sulfate in the range 0 to 0.5 wt% and oil polarities, respectively. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of complex modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. The increasing pattern of complex modulus versus volume fraction has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion. The stability is dependent on: (i) the choice of the oil is important, the requirements coincide with the requirements for the formation of the rigid liquid crystalline phases; and (ii) addition of salts the aqueous phase opposes the instability due to coalescence. Increasing the salt concentration increases the refractive index of the aqueous phase. It lowers the difference in the refractive index between the oil and aqueous phases. This decreases the attraction between the water domains, thus increasing the stability.

• Proceedings of the SCSK Conference
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• 1999.10a
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• pp.65-74
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• 1999

We have studied the stability of W/O high internal phase emulsions(HIPE) containing water, cetyl dimethicone copolyol and oils varying magnesium sulfate in the range 0 to 0.5wt% and oil polarities, respectively. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of concentrated modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. The increasing pattern of complex modulus versus volume fraction has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion. The stability is dependent on: (i) the choice of the oil is important, the requirements coincide with the requirements for the formation of the rigid liquid crystalline phases :5; and (ii) addition of salts the aqueous phase opposes the instability due to coalescence:. Increasing the salt concentration increases the refractive index of the aqueous phase. It lowers the difference in the refractive index between the oil and aqueous phases. This decreases the attraction between the water domains, thus increasing the stability.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.303-306
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• 2003

Indonesia is a tropical country having a temperature range of 25-35$^{\circ}C$ which can affect the skin and causes damages like aging. This aging process is due, at least, to free radical reactions. For this reason, many attempts had been done to find out creams containing natural antioxidant compound which have a potential of free radical scavenger. Kluwek, a fermented form of foot ball fruit or picung (Pangium edule.Reinw), had been proved to contain antioxidant compound in its methanol fraction oil to which antiaging cream was formulated. Stability evaluation was conducted for cream with Kluwek oil compared to base cream, including organoleptic (colour and odour), pH, viscosity, particle size, centrifugation test and flow characteristics either in room temperature (27$^{\circ}C$) or stress condition (4$^{\circ}C$ and 5$0^{\circ}C$) for 8 weeks continuously, and six times cycling test at 4$^{\circ}C$ and 5$0^{\circ}C$ every 24 hours. The results showed that cream with Kluwek oil and base cream were stable at temperature 27 and 4$^{\circ}C$, cycling test and centrifugation test, but not stable at 5$0^{\circ}C$. Free radical evaluation was done by Electron Spin Resonance and the result showed that cream with Kluwek oil had less free radicals compared to base cream.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.95-101
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• 1989

For the utilization of polyunsaturated fatty acids in sardine (Sardinops melanosticta) oil, mainly as a source for dietary supplement of eicosapentaenoic acid(EPA) and docosahe-xaenoic acid(DHA), the effects of refining and storage, conditions, and addition of stabili-zing agents on the storage stability of EPA condensed and refined sardine oil were tested. Refined, sardine oil deacidified, decolored, and deodorized, was more stable to autoxidation than crude or partially purified oils such as deacidified or/and decolored. The refined sardine oil must be kept at $5^{\circ}C$ or lower temperture for longer than two month storage. The addition of $0.018\%\;\alpha-tocopherol$ or BHT could enhance the stability to autoxidation, and EDTA or citric acid was useful as synergist. Especially the addition of $0.02\%$ citric acid to the oil still hot after deodorizing process ($125^{\circ}C$) was of benefit to stabilize the refined oil.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.468-479
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• 1989

The oxidative stability of the ramyon prepared with rapeseed oil fortified with antioxidants or blended with palm oil was studied to explore the possibility of substituting it for Imported frying fats and oils. Natural tocopherols, butylated hydroxyanisole(BHA), tertiarybutyl hydroquinone(TBHQ), and ascorbyl palmitate with citric acid were used at a level of 0.02 percent. Blended oils were prepared by adding a palm oil to the rapeseed oil at ratios of 7:3, 5:5, and 3:7(w/w), respectively. Ramyon samples were stored at $35.0{\pm}0.5^{\circ}C$. for 90 days. The values of parameters, such as peroxide value, unsaturation ratio, and dielectric constant, of the extracted oils were regularly determined. An organoleptic test for the flavor of the samples was also performed. The oxidative stability of the samples was estimated on the basis of the changes of the parameter values. The effectiveness of the antioxidants was in the order of TBHQ ${\gg}$ ascorbyl palmitate with citric acid>BHA>natural tocopherols. The oxidative stability of the ramyon prepared with the rapeseed oil containing 0.02 percent TBHQ was almost as good as that of the ramyon prepared with the palm oil. The stability of the ramyon prepared with the blended oil containing 70 percent palm oil was also as good as that of the ramyon prepared with the palm oil.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.3
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• pp.97-102
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• 1994

The oxidative stability of perilla oil were examined by measuring peroxide value. The induction period of perilla oil for each storage temperature was measured by POV and indicated that it was 80 days for 45$^{\circ}C$, 22.5 days for 65$^{\circ}C$, 9.5 days for 85$^{\circ}C$ and 5 days for 105$^{\circ}C$ respectively. Also, the induction period of the perilla oil with different concentration of ginger powder at 85$^{\circ}C$was studied and has been found that 9.4 days for 6% ginger powder, 11.9 days for 4% and 11days for 2% ginger power. The relative antioxidant effectiveness of ginger power was 99% for 6% ginger power, 125% for 4% ginger power, 122% for 2% ginger power. The induction period of perilla oil with gingerol at 85$^{\circ}C$ was 13.5days for 2% crude gingerol, 11.7days for 0.2% crude gingerol and 12.0 days for 0.02% BHT. The elativi antroxidant effectiveness of perilla oil gingerol at 85$^{\circ}C$was 142% for 2% crude gingerol, 123% for 0.2% crude gingerol, 126% for 0.02% BHT.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.407-414
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• 2009

Water-in-Oil (W/O) emulsions are widely used in cosmetics. However, O/W (Oil-in-Water) emulsions are generally superior to W/O emulsions in terms of stability. In this study, we investigated the changes of viscosity, the size of emulsion droplets, and rheological properties of emulsions prepared using distearyldimonium chloride (DDC), magnesium aluminum silicate (MAS) and quaternium-18 hectorite (QH). In addition to the changes of the composition, we tested the condition of homogenization including rotation per minute of the mixer and the mixing time. The viscosity of emulsions with DDC and AMS were not changed with time and the stability of emulsions was stable during the storage time. However, the fluidity of emulsions were low due to the forming gel network in the emulsions. The gelling power of the emulsions with QH was rather weaker than that of the emulsions with DDC and MAS. The viscosity of emulsions with QH was gradually reduced and the phase separation of emulsions with high concentration of oil was observed throughout the storage time, however, the stability of emulsions with DDC, MAS and QH was excellent, the fluidity of emulsions was enhanced, and the viscosity of emulsions was sustained for a long time after setting of emulsions.

• Tribology and Lubricants
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• v.38 no.2
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• pp.41-52
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• 2022

Mineral electrical insulating oil, which is widely used in transformers, exhibits excellent cooling performance and transformer efficiency. However, given that it is composed of petroleum-based components, it is weak in terms of biodegradability. This causes environmental problems in case of leakage and a low flash point, which is a factor that would cause great damage in the event of a fire in a substation. In this context, the use of eco-friendly electric insulating oil composed of bio-based vegetable oil and synthetic ester, which has excellent biodegradability and flame retardancy performance, has recently been expanded to the field of electric power, and various research and development (R&D) studies are in progress. According to different research results, vegetable oil and synthetic ester manufacturing technology, thermal stability, oxidation stability, property change, and quality control, which are characteristics of eco-friendly electrical insulating oils, are major factors affecting the maintenance of insulating oil properties. In addition, power companies have established and operated quality control standards according to the use of eco-friendly electrical insulating oil as they expand the exploitatoin of renewable energy in electricity production. In particular, deterioration and oxidation characteristics were jointly identified in R&D as an important influencing factor according to the content of saturated and unsaturated fatty acids present in vegetable oils and synthetic esters in power transformer applications.

• 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.