• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.15-21
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• 2013

This study investigated the oxidative stability of oils when dough was fried under a lower pressure than the ambient atmosphere. The pressure during the frying process was controlled at measures of 760, 560, 360 or 160 mmHg. The oil containing the dough was heated at $180^{\circ}C$ for 48 hours. Rancidity values, including acid value, peroxide value, fatty acid analysis, color changes, and browning of oil samples, were measured every 8 hours. As the frying process continued at all 4 pressure levels, the acid values (AV) increased. However, compared to the other pressure levels, the increase in AV was the least at 160 mmHg. In addition, the peroxide value at 160 mmHg was only 0.81 meq/kg compared to 1.52 meq/kg at 760 mmHg. For all pressure levels, stearic acid, oleic acid, ${\omega}$-6 linolenic acid were increased, while linoleic acid and ${\omega}$-3 linolenic acid were decreased. In terms of color, a-values representing redness were decreased, whereas b-values were increased as the frying proceeded. These results revealed that the oxidation of frying oil was decreased under reduced pressure condition. Thus, the usage of frying oil may be extended, owing to less oxidative concerns. This leads to a lower cost to the manufacturer, and furthermore, helps the environment by reducing industrial wastes.

• Journal of Biosystems Engineering
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• v.26 no.3
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• pp.209-220
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• 2001

This study was carried out to investigate the usability of the used frying oil, which was extracted from soybean, as one of the alternative fuel of a small diesel engine. For the experiment, NO. 2 diesel oil [D], used frying oil [UF], and their volumetric blends were applied and analysis of the properties and compositions of the experimental fuels were conducted. A four cycle diesel engine with single cylinder, water cooling system, maximum output 8.1 ㎾/2,200 rpm was selected and a direct injection chamber and a precombustion chamber were attached alternately. The results obtained were as follows: 1. Engine power (BHP) were increased from 4.13~4.27㎾ to 9.08~9.15㎾ for diesel oil, from 4.05~4.19㎾ to 8.44~8.92㎾ for UF, and from 4.01~4.48㎾ to 8.69~9.16㎾ for blend fuel, as the engine speed increased from 1,000 rpm to 2,200 rpm. The BHP in case of the direct combustion chamber were fluctuated higher than those of the pre-combustion chamber. 2. With the engine speed increased, torque of the engine were increased from 39.50~40.80 N.m to 42.89 N.m, then decreased to 39.44~39.77 N.m for diesel oil, and increased from 38.73~40.04 N.m to 40.12~40.82 N.m then decreased as 36.53~38.76 N.m for UF. Torque of the blend fuels were increased from 38.75~41.76 N.m to 40.47~42.89 N.m then decreased to 37.73~39.78 N.m. There is no significant difference of torque between the type of combustion chambers. 3. The specific fuel consumption of the UF was increased about 20 percent depending on the engine speed variations. And in case of direct injection chamber, about 12 percent lower fuel consumption was observed than that of precombustion chamber. 4. NOx emission of the UF was higher than that of diesel oil at above 1,800rpm of the engine speed. In case of the direct injection chamber, NOx emission was revealed higher about 59 percent than that of the precombustion chamber, depending on the range of the engine speeds. 5. Smoke emission was decreased in case of UF compared with diesel oil on direct injection chamber. When using precombustion chamber smoke emission was a little higher than that of the direct injection chamber were showed at the engine speed range. 6. At all the engine speed range, exhaust gas temperatures were decreased 2~3$^{\circ}C$ for UF used engine compared with those of the diesel oil. The exhaust gas temperature of the direct injection chamber was higher than that of the precombustion chamber by 72$^{\circ}C$. 7. Unburnt materials remained in the cylinder in case of the pre-combustion chamber was smaller and softer than that of the direct combustion chamber. 8. The feasibility of the blend fuel B-1 and B-2 were verified as a direct combustion chamber was attached to the diesel engine, with respect to the power performance of the engine.

• 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.

• Particle and aerosol research
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• v.16 no.1
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• pp.9-17
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• 2020

The characteristics of particulate matter made from daily cooking at a Korean residential apartment house with three dwellers had been investigated for about 3 months. All data were recorded by an optical particle counter every minute at the kitchen. Types of cooking such as boiling, frying, and grilling that performed in the house were listed. Boiling only was used in 32% cases among total 234 meals. Frying and grilling were 14% and 11%, respectively. From an initial indoor particulate matter smaller than 10 ㎛ in diameter, the increases due to cooking are reported by size. In case of boiling, PM at 1-10 ㎛ size and under 1 ㎛ size little increased. Normally, particles from oil or combustion in a process of frying or grilling increased indoor PM. In a case of grilling, particle mass concentration in a region of 1-10 ㎛ in diameter increased as much as 295 ㎍/㎥. Mass concentration of particles smaller than 1 ㎛ increased as much as 33 ㎍/㎥.

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.214-221
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• 2008

The production of biodiesel by transesterification of waste frying oil was conducted on various zeolite catalysts with different acidity and pore structure. $H^+$ ion exchanged MOR, MFI, FAU, and BEA zeolites were employed in the reaction with silicalite which has no strong acid sites. $H^+$ ion exchanged MOR(10) zeolite, which has more acid sites and stronger acid strength than other zeolites, exhibited the highest methyl esters yield as 95%. Dealumination to the HMOR zeolite induced decreasing of acid amount and acid strength. It brought about the decrease of fatty acid methyl esters (FAME) yield. The yield increased linearly with enhancing of acid strength and increasing of amount of strong acid sites. The yields were independent on pore structure of the zeolites.

• Korean Journal of Food Science and Technology
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• v.17 no.2
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• pp.114-120
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• 1985

This study was carried out to investigate the storage stability of Yackwa (a Korean fried cake made from wheat flour, honey and 20% oil), with the variation in frying oils (soybean oil of fresh or heat-treated corn oil and rapeseed oil) and storage conditions (temperature, humidity and in dark or under fluorescent light) for 20 weeks period. In $5^{\circ}C$ storage, acid and peroxide values increased slowly, showing the peroxide value of 20 meq/kg after 13 weeks. In $40^{\circ}C$ storage, acid and peroxide values increased remarkably. The product became harder at storage humidity of 25% and softer by moistening at storage humidity of 80%. Acid and peroxide values of Yackwa from corn, rapeseed and soybean oils increased with storage period, to a different extent. The values of fluorescent groups, especially rapeseed oil group, were higher than those of control groups and the heat-treated oil groups were higher than those of fresh oil groups. Sensory scores for rancid flavor were gradually increased with the storage period in all groups. There was no significant difference with the kinds of frying oils, storage conditions and heat treatment. Correlation of sensory scores with acid values was positive throughout whole storage period, with low ${\gamma}-values$. Its correlation with peroxide values was positive up to 6th week but negative at 9th week of storage.

• Korean journal of food and cookery science
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• v.27 no.6
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• pp.671-680
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• 2011

In this study, frying mix was prepared containing 0.5, 1.0, 1.5 or 2.0% brown rice fiber(BRF). The samples along with a control were then compared regarding their quality characteristics, including pasting properties, spreadability, pick-up ratio, color, textural characteristics, moisture and oil contents, and sensory qualities, all to determine the optimal ratio of BRF. For the pasting properties of frying mix, the control group was evidenced by a significantly higher peak viscosity, through viscosity, and final viscosity than that observed in the BRF samples. Breakdown was the highest at the 1.0% addition level, and time to peak viscosity and pasting temperature were maximal with the 0.5% addition. There was no significant difference in setback among the experiments. Spreadability and pick-up ratio of frying batter were not significantly different among the samples. As the BRF content increased, the lightness, greenness decreased, whereas yellowness increased. The BRF samples presented significantly higher hardness of fried batter than the control group and there was no significant difference in crispiness among the samples. Moisture content of fried sweet potato decreased with increasing BRF and oil content was the maximum on the control group. In the sensory evaluation, appearance, color, flavor, savory taste, yellowishness, coating thickness, off-flavor, and oiliness were not significantly different among the fried sweet potato samples. Bindingness, crispiness, and chewiness were highest in the control samples but minimal at a addition level of 2.0%. The control group evidenced significantly higher overall acceptability than were observed in the BRF samples. In conclusion, the results demonstrated that 0.5~1.0% BRF may prove quite useful as a additive for frying mix in the preparation of fried sweet potato and may provide favorable textural and functional properties.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1238-1249
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• 2023

In this study, we sought to investigate the production and optimization of biosurfactants by soil fungi isolated from petroleum oil-contaminated soil in Saudi Arabia. Forty-four fungal isolates were isolated from ten petroleum oil-contaminated soil samples. All isolates were identified using the internal transcribed spacer (ITS) region, and biosurfactant screening showed that thirty-nine of the isolates were positive. Aspergillus niger SA1 was the highest biosurfactant producer, demonstrating surface tension, drop collapsing, oil displacement, and an emulsification index (E₂₄) of 35.8 mN/m, 0.55 cm, 6.7 cm, and 70%, respectively. This isolate was therefore selected for biosurfactant optimization using the Fit Group model. The biosurfactant yield was increased 1.22 times higher than in the nonoptimized medium (8.02 g/l) under conditions of pH 6, temperature 35℃, waste frying oil (5.5 g), agitation rate of 200 rpm, and an incubation period of 7 days. Model significance and fitness analysis had an RMSE score of 0.852 and a p-value of 0.0016. The biosurfactant activities were surface tension (35.8 mN/m), drop collapsing (0.7 cm), oil displacement (4.5 cm), and E₂₄ (65.0%). The time course of biosurfactant production was a growth-associated phase. The main outputs of the mathematical model for biomass yield were Yx/s (1.18), and µ_max (0.0306) for biosurfactant yield was Y_p/s (1.87) and Y_p/x (2.51); for waste frying oil consumption the So was 55 g/l, and Ke was 2.56. To verify the model's accuracy, percentage errors between biomass and biosurfactant yields were determined by experimental work and calculated using model equations. The average error of biomass yield was 2.68%, and the average error percentage of biosurfactant yield was 3.39%.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.635-640
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• 1997

The oxidative stability of the potato chip prepared with canola oil fortified with antioxidnats was studied to explore the possibility of substituting it for imported frying fats and oils. BHT, BHA, TBHQ and silicone were added to the oil at a level of 0.02% and 10 ppm, respectively. Potato chip samples were prepared in a commercial scale and stored at $25.0{\pm}0.5^{\circ}C$ for 5 months. The oxidative stability of the extracted oils from potato chips during storage was estimated on the basis of some their physico-chemical changes, such as acid values, peroxide values, iodine values, ansidine values, fatty acid composition of the oils. An organoleptic test for the flavor of the samples was also performed. The oxidative stability of the samlpes was estimated on the basis of the changes of the parameter values. The effectiveness of the antioxidants was in the order of canola oil+TBHQ (0.02%)+silicone (10 ppm) > canola oil+TBHQ (0.02%) > canola oil+BHA (0.02%)+silicone (10 ppm) > canola oil+BHT (0.02%)+silicone (10 ppm) > canola oil+BHA (0.02%) > canola oil+BHT (0.02%) > canola oil. The antioxidant effect of canola oil+TBHQ (0.02%)+silicone (10 ppm) was more salient than any other antioxidant used in the potato chip.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.2
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• pp.223-228
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• 1989

In order to modelize the pretreatment procedure of the cyanide-free apricot seed oil, the conditions of crushing, frying, drying and steaming were investigated. Hydrogen cyanide was formed in the crushed seed at wide temperature range of $5{\sim}70^{\circ}C$, and the highest formation temperature was $40^{\circ}C$. The cyanide content in the crushed seeds incubated 5 and $40^{\circ}C$ for 96 hours was 200 and $780{\mu}g/g$ respectively, however the cyanide contained small amount in the non-crushed seeds. Consequently, emulsin inactivaton procedure was required for the preparation of cyanide-free oil. Steaming for 15 min. was the most desirable pretreatment procedure for the cyanide-free apricot seed oil. But oil production from the steamed seeds was lower than those from frying.