• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.146-151
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• 1987

The storage stability of sardine oil and the effect of BHA on the oxidation of fatty acids especially, highly unsatureted fatty acids like EPA and DHA were investigated. The sardine oil was extracted from round sardine, with chloroform-methanol(2:1 v/v) solvent with/without addition of BHA, and then stored at $30^{\circ}C$. The deterioration of oil was examined periodically by measuring acid value(AV), peroxide value(POV), carbonyl value(COV), and oxygen absorption. The changes in fatty acid composition during the storage was determined by GLC analysis to elucidate the oxidative stability of individual fatty acid. Formation of free fatty acid increased rapidly according to the storage time elapsed in the BHA free oil while it was obviously inhibited in the BHA added oil. Peroxides and carbonyl compounds were formed very rapidly at the beginning of storage of BHA free oil. But in the oil extracted with BHA, formation of peroxides was somewhat inhibited and formation of carbonyl compounds was very strongly inhibited. Principal fatty acids of sardine oil were $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{20:5}\;and\;C_{22:6}$ acids, and $\omega_33$ polyunsaturated fatty acid $(\omega_3\;PUFA)$ content was very high as much as $23\%$ of the total fatty acid content. The oxidative degradation of fatty acids was enhanced at PUFA especially $C_{20:5}$ ana $C_{22:6}$ acid in BHA free oil. However, the oxidation was fairly retarded in the oil extracted with BHA and the both $C_{20:5}$ and $C_{22:6}$ acids remained at the end of a month storage.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.562-568
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• 2021

An O/W (oil in water) emulsion, wheat germ oil raw material, was produced by using natural wheat germ oil and composite sugar-ester. The effects of variables such as the hydrophile-lipophile balance (HLB) value, added emulsifier amount, and emulsification time on the average particle size, emulsification viscosity and ESI of O/W wheat germ oil emulsion were investigated. The parameters of the emulsification process produced by the central composite design model of the response surface methodology (CCD-RSM), which is a reaction surface analysis method, were simulated and optimized. The optimum process conditions obtained from this paper for the production of O/W wheat germ oil emulsion were 8.4, 6.4 wt%, 25.4 min for the HLB value, amount of emulsifier, and emulsion time, respectively. The predicted reaction values by CCD-RSM model under the optimum conditions were 206 nm, 8125 cP, and 98.2% for mean droplet size (MDS), viscosity, and ESI, respectively, based on the emulsion after 7 days. The MDS, viscosity and ESI of the emulsion obtained from actual experiments were 209 nm, 7974 cP and 98.7%, respectively. Therefore, it was possible to design an optimization process for evaluating the stability of the emulsion of wheat germ oil raw material by CCD-RSM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.521-524
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• 2003

This paper is aimed to develop the circuit of a coil-type oil sensor packaged to the automotive engine oil monitoring the deterioration in the driving condition and let a driver notify the optimized time for the exchange of engine oil. By applying the principle which the deterioration of automotive engine oil can be expressed to the dielectric constant, the capacitance bridge circuit and the integrator circuit are designed and packaged to a coil-typed engine oil. In this study. the range of operating temperature of engine oil is experimentally recommended within 55$^{\circ}C$ for the stability of a sensor designed. It is concluded that the characteristics of output voltage converted from the dielectric constant are linearly distributed.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.3 s.192
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• pp.61-66
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• 2007

This work is aimed to measure the deterioration in oil sensor. For the study, the circuit of a coil-type oil sensor packaged was developed and applied to the automobile engine for monitoring the deterioration of engine oil in driving conditions. From the principle which the deterioration of automobile engine oil can be expressed to the dielectric constant, the capacitance bridge circuit and the integrator circuit were designed. As results, the range of operating temperature of engine oil was experimentally recommended within $55^{\circ}C$ for the stability of a sensor designed. It was also concluded that the characteristics of output voltage converted from the dielectric constant were linearly distributed and predicted the optimized time for the exchange of engine oil.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2333-2341
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• 2017

Mineral oils are commonly used as transformer insulation oils but these oils are obtained from non-renewable and non-sustainable sources, which is highly undesirable. For this reason, natural ester oils are now being used in replacement of mineral oils because of their good biodegradability, high cooling stability, good oxidation stability and excellent insulation performance. Nanotechnology has gained prominence in both academic and industrial fields over the years and it has been shown in previous studies that nanoscale materials are useful for transformers due to their favourable dielectric properties. The objective of this study is to compare the AC breakdown voltage and viscosity of natural ester oil with three types of nanofluids. The natural ester oil-based nanofluids are prepared by mixing palm fatty acid ester (PFAE) oil with three types of nanoparticles at a concentration of 0.01 g/l: (1) $Fe_3O_4$ conductive nanoparticles, (2) $TiO_2$ semi-conductive nanoparticles and (3) $Al_2O_3$ insulating nanoparticles. The AC breakdown voltage of the oil samples is analysed using Weibull statistical analysis and the results reveal that the PFAE oil-based $Fe_3O_4$ nanofluid gives exceptional dielectric performance compared to other oil samples, whereby the AC breakdown voltage increases by 43%. It can be concluded that the PFAE oil-based $Fe_3O_4$ nanofluid is a promising dielectric liquid to substitute mineral oils.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.258-264
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• 2015

This study was conducted to evaluate emulsion mapping between emulsion stability and cooking yields, apparent viscosity, and hardness of reduced-fat pork emulsion systems. The reduced-fat emulsion systems were supplemented with different lipid types and brown rice bran fiber (BRF) concentrations. Compared to the control with 30% back fat, lower emulsion stability and higher cooking yield of meat emulsion systems were observed in T1 (30% back fat+1% BRF), T2 (30% back fat+2% BRF), T3 (30% back fat+3% BRF), T4 (30% back fat+6% BRF), and T15 (10% back fat+10% canola oil+2% BRF). Lower emulsion stability and higher apparent viscosity were observed in T1, T2, T3, T4, and T8 (20% back fat+3% BRF) compared to the control. Lower emulsion stability and higher hardness was detected in all treatments compared with the control, except T5 (20% back fat), T10 (10% back fat+10% canola oil+2% BRF), T11 (10% back fat+10% olive oil+2% BRF), T12 (10% back fat+10% grape seed oil+2% BRF), and T13 (10% back fat+10% soybean oil+2% BRF). This approach has been found particularly useful for highlighting differences among the emulsified properties in emulsion meat products. Thus, the results obtained with emulsion mapping are useful in making emulsified meat products of desired quality characteristics, partially replacing pork back fat with a mix of 10% back fat, 10% canola oil and 2% BRF was most similar to the control with 30% pork back fat.

• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.356-364
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• 2021

This study was carried out to investigate the effects of supercritical carbon dioxide (SC-CO₂) extracts from sweet potatoes (SP) and watermelon (WM) on the oxidative stability of perilla seed oils (POs) over the existing ones. A comparison was done between the oxidative stability of perilla oil (PO) after the addition of 0.1% of SP, and WM extracts and PO without extract. The oxidative stability was measured based on the viscosity, acid value (AV), peroxide value (POV), antioxidant (DPPH) activity, p-anisidine value (p-AV), and fatty acid composition. The viscosities ranges were: PO without extract, from 53.99±0.99 to 74.38±1.61 cps, PO with SP extract, from 53.99±0.10 to 58.73±0.8 cps, and PO with WM extract, from 53.98±0.10 to 56.00±0.70 cps. While the PO containing the SC-CO₂ extracts had significantly lower AV, POV, and p-AV, their antioxidant activity was approximately 10 times higher than that of the PO without extract. There were no significant differences in fatty acid composition between SC-CO₂ extracts added groups and PO without extract (p<0.05). The findings of this study confirmed that the SC-CO₂ extracts from sweet potatoes and watermelon enhanced the oxidative stability of perilla seed oils, and are potential natural antioxidants for use in the food industry.

• The Korean Journal of Food And Nutrition
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• v.27 no.6
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• pp.1132-1140
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• 2014

This study aimed to investigate the changes in antioxidant activities, quality characteristics, and storage stability of mayonnaise prepared with perilla oil with the addition of mulberry powder ranging from 0 to 5%. The antioxidant activities of perilla oil mayonnaise (PM), as determined by DPPH and ABTS radical scavenging activity, as well as FRAP and total phenolics content were improved by the addition of mulberry powder compared with the control sample. Antioxidant activities were dependent on the amount of mulberry powder added. Lipid oxidation of PM decreased with a higher amount of mulberry powder, based on measurements of peroxide value. The emulsion stability of PM increased with decreases in the amount of mulberry powder level. The a-value in PM color increased with increasing amount of mulberry powder. Sensory evaluation showed that the highest score in overall acceptability of PM was achieved with 4% mulberry.

• YAKHAK HOEJI
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• v.40 no.3
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• pp.243-250
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• 1996

In order to formulate aqueous multivitamin solutions containing both oil-soluble (A, D, E) and water-soluble vitmains ($B_1,\;B_2,\;B_6,\;B_{12}$, C and niacinamide) in 1ml-dose, the effects of various additives such as cosolvents (propylene glycol, polyethylene glycol, glycerin), a sweetener (sorbitol) and a surfactant (Cremophor$^{\circledR}$ RH40) on the solubility of oil-soluble vitamins in water were evaluated. Cremophor$^{\circledR}$ RH40 showed the excellent capacity on the solubilization of oil-soluble vitamins, and the simultaneous addition of cosolvents and surfactant resulted in synergetic effects on the solubilization of oil-soluble vitamins. The effects of the combination of the cosolvents and sweetener on the stability of multivitamin solutions were also evaluated by determining the amount of vitmain A and $B_1$ remained in the solutions after storing at $40^{\circ}C$ for 9 weeks. The formulation consisting of Cremophor$^{\circledR}$ RH40 15%, PG 20%, and sorbitol 20% resulted in the best stability of vitamin A and $B_1$. The stability of vitamin A and $B_1$ in this formulation was evaluated at 50, 60, and $70^{\circ}C$ up to 40 days. The shelf-lives of vitamin A and $B_1$ in the formulation, calculated using the Arrhenius equation, were 1,521 days and 475 days at $20^{\circ}C$, respectively.

• Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.21-26
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• 2015

Seasoned laver Pyropia spp. is a traditional Korean seafood that has gained popularity worldwide because of its unique taste, texture, and health benefits. It is prepared by roasting a sheet of dried laver, to which vegetable oils have been applied, at an ultra-high temperature (UHT) of $300^{\circ}C$. Therefore, the oxidative stability of the oils is the most important factor in determining the shelf life of seasoned laver products. In this study, we investigated changes in the thermal oxidative stability of six major vegetable oils (sesame, perilla, sunflower, rice bran, canola, and olive) during the seasoned laver processing. The oxidation induction time of each oil from the seasoned laver products was decreased compared with the fresh oil. These results indicate that the UHT treatment ($300^{\circ}C$, 10 s) induced thermal oxidation of the oils. Among the six seasoned laver oils, the induction times of olive (OL, 8.02 h) and sesame (SE, 5.31 h) oils were significantly higher than the other oils. The acid values (AVs) of OL and SE oils from the seasoned laver were 0.49 and 0.79, respectively. On the other hand, perilla oil had the overall worst thermal oxidative properties (induction time: 0.35 h, AV: 2.82). Our results provide useful information about seasoned laver products for researchers or manufactures.