• 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.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.225-230
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• 1988

Emulsion stability, viscosity, and oil particle size of mayonnaise, prepared at various egg yolk contents, were investigated. With increasing of the egg yolk ratio, emulsion stability became stronger, viscosity became higher, and oil particle size became smaller. Freezing stability of mayonnaise containing below 6.5% egg yolk was reduced significantly. Referring to vibration separation, it was observed that stability of mayonnaise containing 2% and 3.5% egg yolk was very low and containing over 5% egg yolk was stable relatively. Viscosity of mayonnaise, stored at $-10^{\circ}C$, was reduced significantly during first 24hrs. and then levelled off. Oil particle size of mayonnaise, stored at $-10^{\circ}C$, became larger with increasing the storage time and the tendency to change was apparent in the sample containing below 6.5% egg yolk.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.237-246
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• 2014

Multiple emulsions, called multiphase emulsions, include water-in-oil-in-water (W/O/W) type and oil-in-water-in-oil (O/W/O) type emulsions. In cosmetic industry, they are used to stabilize active ingredients but the applicability of the multiple emulsions is limited because of low stability and difficulty of manufacturing. In this study, we investigated a two-step emulsification process for a W/O/W type emulsion. We also investigated the change of stability using different emulsifiers and oil polarity. The results suggested that polyglyceryl-10 stearate, as a main emulsifier, played an important role in the stability and the formation of the multiple emulsions.

• Journal of the Korean Society of Food Culture
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• v.24 no.3
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• pp.344-349
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• 2009

The principal objective of this study was to assess the effects of various ratios of sesame oil to shortening on the characteristics and stability of lipids in Yackwa. The sesame oil to shortening ratios assessed herein were 100:0, 75:25, 50:50, and 1:100. The lipid contents of Yackwa prepared with various shortening ratios ranged from 25.20 to 29.12%. The lipids in these Yackwa consisted primarily of the frying oil (soybean oil), and the oil contents were measured between 84-90%. The fatty acid compositions of the lipids in the Yackwa were unrelated to the ratio of shortening. The fatty acid compositions were as follows: linoleic acid 49.1-51.27%, oleic acid 26.05-26.77%, palmitic acid 10.07-11.71%, linolenic acid 5.51-5.72% and stearic acid 4.51-4.68%. These compositions were similar to that of soybean oil, which was the frying oil used to prepare the Yackwa. The acid value, peroxide value, and carbonyl value of the lipids in Yackwa did not differ with the various shortening ratios used during the storage time. Stability of lipids in Yackwa were mainly effected by frying oil. Our results suggest that shortening should prove useful as a substitute for sesame oil in the preparation of Yackwa.

• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.44-52
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• 2000

The dispersion of surface oil is generally described as a break-up of oil slick into small oil droplets. These small droplets are subjected to turbulence and vertical circulation so that it can be entrained into subsurface. Sometimes they tend to be submerged into sea bottom permanently. The diameter of oil droplets is a critical parameter to determine their behavioral characteristics under water surface. At the same time the variations of droplet stability depends on the weathering of it. That is why the weathered oil has different mechanism from the unweathered one. The variability of physical properties of oil including viscosity and density contribute to interfere with effective separation of oil and emulsion droplets in water. Also in the presence of interactions among the droplets there are coalescing or coagulating effects on the dispersion process of droplets.

• Food Science and Preservation
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• v.15 no.3
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• pp.437-444
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• 2008

Structured lipids(SLs) were synthesized by enzymatic interesterification with DHA-enriched fish oil(containing 27% docosahexaenoic acid) and soybean oil in the hatch-type reactor. The interesterification was performed for 24 hr at $55^{\circ}C$ and TLIM(immobilized lipase from Thermonyces lanuginosa, 10% by weight of total substrates) was mixed with 180 rpm of shaking. The fish oil and soybean oil were interesterifed with several weight ratio(fish oil : soybean oil, 2:8, 3:7, 4:6, 5:5, w:w), Reverse-phase high performance liquid chromatography with an evaporative light-scattering detector separated the triglyceride species of SLs. The products contained the newly synthesized peaks. Especially, one of peaks was distinctively increased with the increasing weight ratio from 2:8 to 5:5 while the peak of trilinolein (LLL) decreased vice versa. The effect of antioxidants such as catechin, BHT(Butylated hydroxytoluene), and their combinations on the oxidative stability in SL were investigated. Oxidative stability was carried out under oven test at $60^{\circ}C$ over 72 hr thereafter SLs were analyzed for total fatty acid content, rancimat, peroxide value, electronic nose and TBARS value. Among all combinations of antioxidant, the highest stability was obtained from 200 ppm of catechin. Besides, total tocopherol ($\alpha$, $\gamma$, and $\delta$-tocopherol), iodine and saponification value were analyzed in which iodine and saponification value of SLs were 151.19 and 182.35.

• Korean Journal of Food Science and Technology
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• v.19 no.1
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• pp.23-28
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• 1987

The effects of phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl inositol (PI), phosphatidic acid (PA), phosphatidyl glycerol (PG), and cardiolipin (CL) on the flavor stability of purified soybean oil were studied. Purified soybean oil obtained from soybean oil by silicic acid chromatography does not contain measurable iron, tocopherols and phospholipids. Three hundred ppm of PC, PE, PI, PA, PG, or CL was added to the purified soybean oil, with and without 1ppm ferrous iron added. The flavor stability of sample, which was stored at $60^{\circ}C$ for 10 days in dark oven, was determined by a combination of volatile compounds formation and molecular oxygen disappearence in the headspace of air-tightly sealed serum bottle every 48 hrs. Results showed that, in general, phospholipids worked as prooxidant in the pufified soybean oil without ferrous iron added, and worked as antioxidant in the oil, when added 1ppm ferrous iron. The results also suggest that phospholipids work as prooxidant by increasing the solubility of oxygen on the surface of oil, and work as antioxidant in the oil containing 1 ppm ferrous iron by chelating iron. The results showed that PE and PA are better antioxidants than PC and PG. CL and PI showed the lest antioxidant activities in the oil will 1ppm ferrous iron added.

• Tribology and Lubricants
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• v.27 no.3
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• pp.125-133
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• 2011

The purpose of this study is to develop an engine oil quality monitoring system to warn the abnormal condition of engine oil. To do this, first of all, it is needed a personal controller development to measure the capacitance of a pre-developed engine oil deterioration detection sensor integrated with an oil filter. To measure the capacitance of engine oil in the sensor, it is used the way measuring the electric charging time in a capacitor by impressing DC volt. This method has merits on cost and signal stability. The measured capacitance is compensated by comparing with the one measured by an impedance analyzer. Also, using the dielectric constant gained by an impedance analyzer, the calculating equation of the dielectric constant of engine oil related with the currently developed sensor is decided. Then, the deterioration degree of engine oil is estimated according to the change rate of dielectric constant between green oil and used oil. Finally, using this dielectric constant information together with engine oil temperature and pressure, the currently developed engine oil quality monitoring system is to tell the abnormal state of engine oil.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.315-321
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• 2015

The aim of the present work was to investigate the effect of NaCl concentration on the emulsifying and rheological properties of porcine myofibrillar protein (MF)-stabilized soybean oil and fish oil emulsion (SO-EMs and FO-EMs). Emulsions (EMs) were prepared from 1% MF with 10% SO or FO at various NaCl concentration (0-0.5 M). The emulsifying ability index (EAI) of the EMs increased with increasing NaCl concentration for both oil types. Conversely, increasing NaCl manifested decrease in the emulsion stability index (ESI). In addition, creaming index (CI) also increased with NaCl concentration. From the microscopic observation, droplets of the EMs were more aggregated at relatively higher NaCl concentrations, especially for FO-EMs. All EMs had a gel-like structure owing to G' > G" from the rheological analysis. Comparing the oil types, the emulsifying capacity of SO-EMs was more stable than that of FO-EMs at all NaCl concentrations as determined from the CI value and microscopic observation. Therefore, it can be concluded that SO-EMs and FO-EMs are more stable at relatively lower concentrations of NaCl. In addition, the dispersed stability of SO-EMs was better than that of FO-EMs at the same concentration of NaCl.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.438-443
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• 1993

Physico-chemical properties of glucitol fatty acid polyesters (GPE)-one of the potential fat substitutes-were analyzed and compared with conventional edible oil. The refractive Index, apparent viscosity and melting point of S-GPE (soybean oil GPE) were 1.472, 103 cps. at $37^{circ}C\;and\;-53^{\circ}C$, respectively. S-GPE were liquid at room teperature and the Yellowness of S-GPE was slightly stronger than that of soybean oil. The acid value and smoke point of S-GPE were 0.06 and $200^{\circ}C$. To supplement the weak thermal stability of S-PEG, SP-GPE (soybean-palm blended oil GPE) was prepared with soybeanpalm blended oil (70% of soybean oil and 30% of palm oil). The appearance and color of SP-GPE was not much different from S-GPE but the smoke point of that was increased to $210^{\circ}C$. It means that thermal stability of GPE can be enhanced by increasing saturation of the fatty acid composing GPE. Because most of physico-chemical properties of S-GPE or SP-GPE were similar to conventional edible oil, they are expected to be considered as a potential fat substitute with further study for confirming the safety.