• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.286-290
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• 2007

The esterification efficiency of several ionic liquids has been investigated to determine the feasibility for the conversion of free fatty acids to alkylester. Five ionic liquid catalysts having strong acidity, BPC[$AlCl_3$], BMIM[$Bf_4$], BMIM[$Pf_6$], EMIM[$Ntf_2$], BMIM[Otf], have been employed in this work. BPC[$AlCl_3$] has the highest esterification efficiency among the ionic liquid catalysts. Over 90% conversion efficiency has been achieved in the esterification of the simulated used cooking oil by BPC[$AlCl_3$] with two hours reaction time. Since BPC[$AlCl_3$] has several advantages such as high esterification activity, ease of separation from reaction mixture and reusability after treatment procedure, it will be a promising catalyst for the conversion of free fatty acids to esters in waste fats.

• 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 CROP SCIENCE
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• v.59 no.4
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• pp.413-426
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• 2014

This study was conducted to investigate changes of physicochemical properties and fatty acid compositions of rough rice stored at different storage temperatures and periods. So we analyzed texture, alkali digestion value (ADV), toyo glossiness value, pasting properties, fat acidity and fatty acid compositions of five rice varieties every 4 month on the condition of which rough rice had been stored at different temperatures (ambient and low temperature condition at $15^{\circ}C$) for 2 years. Hardness of cooked rice was increased by storage periods and cohesiveness of cooked rice was not considerably different among varieties according to storage temperatures and periods. ADV was significantly different among varieties and storage periods but not different with storage temperatures. Toyo glossiness value of cooked rice was continuously decreased from 4 months after storage regardless to storage temperature. The pasting properties were considerably affected by storage temperatures and periods of rough rice. Increase in peak viscosity, final viscosity and breakdown was observed but setback was decreased by storage periods. Fat acidity of brown rice was much higher than that of milled rice during storage of rough rice and tend to increase by storage period. Oleic acid among fatty acids of brown rice except Sindongin and Hitomebore tended to be decreased by storage periods and linoleic acid among fatty acids of brown rice of Hopum was decreased by storage periods. The contents of linoleinic acid and stearic acid among fatty acids of milled rice were comparatively decreased from 4 months after storage, whereas the content of palmitic acid tended to be increased by storage periods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.266-270
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• 1991

Storage in the form of brown or milled rice saves space and cut cost rather than storage of rough rice, the common way of grain storage in Korea. But, brown or milled rice may be more susceptable to grain aging and sensory change than rough rice. Rice stored in government warehouse for 20 months after harvest was hulled into brown or milled rice and packaged with kraft paper bag (paper package), polyprophylen (PP package), and polyethylene (PE package). Then, after those rice packages were stored under room condition for one year, we investigated germinability, fat acidity, and sensory change to determine milling and packaging effects. Germinability of rough and brown rice was decreased significantly after long-term storge. In germination rate, Chucheong cultivar was lower than Milyang #23, brown rice was lower than rough rice, but there was no differences within packaging materials. TTC test which had a significant correlation with germinability can be used as a handy procedure for predicting grain germination. Fat acidity was increased as the order of rough < milled < brown rice in terms of milling, and PP < paper < PE package in terms of packaging materials. Especially, storage of brown rice increased fat acidity above 30 mg KOH, indicating one of characteristics of grain aging. To prevent from high fat acidity it was necessary to store in forms of rough grain with paper or PP packaging and milled rice with paper, or PP, or PE packaging. In sensory test of stored grain, eating quality in brown rice was the worst because of acidification of fatty acid. Also, eating quality of stored grain became worse as fat acidity increased.

• Korean journal of food and cookery science
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• v.16 no.2
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• pp.121-127
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• 2000

To assess the quality characteristics of home-made Doenjang prepared by traditional methods, general components, organic acids, amino acids and fatty acid composition of Doenjang were investigated. The contents of moisture, crude protein, crude lipid, salt and the titratable acidity(as milliliter of 0.1 N NaOH consumed) of Doenjang were 57.3%, 11.6%, 8.3%, 13.9%, and 11.8, respectively. There were wide variation in the contents of crude protein and salt among all samples. The average content of amino type nitrogen was 308.4mg%(w/w), however, it ranged from 202.3 to 416.3 mg% in which the contents some samples were 1.3∼2.1 folds greater than others. Hunter color values of L(lightness), a(redness) and b(yellowness) were 37.3, +19.6, and +17.5, respectively. Browning index value(expressed as optical density at 425 nm) of water-soluble compound(2.23) was more than 5.7 times higher than that of water-insoluble compound(0.39). The contents of free and total amino acids were 2908.9 and 9019.3 mg%, respectively, and the range of free amino acids(1.8∼6.2 times) were much wider than the range of total amino acids(1.2∼2.0 times). Glutamic acid was most abundant in free and total amino acids as 576 and 1,126 mg%, respectively. The main organic acid was lactic acid as 326.8 mg% ranging from 59.4 to 613.4 mg%. Linoleic acid(49.24%) showed the highest content in total fatty acids. Unsaturated fatty acid comprised 81.97% of total fatty acids and polyunsaturated fatty acid ranged from 51.79 to 62.97%.

• Analytical Science and Technology
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• v.30 no.4
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• pp.174-181
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• 2017

Bio-liquid is a liquid by-product of the hydrothermal carbonization (HTC) reaction, converting wet biomass into solid hydrochar, bio-liquid, and bio-gas. Since bio-liquid contains various compounds, it requires efficient sampling method to extract the target compounds from bio-liquid. In this research, fatty acid methyl ester (FAME) in bio-liquid was extracted based on hollow fiber supported liquid phase microextraction (HF-LPME) and determined by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography/Mass Spectrometry (GC/MS). The well-known major components of biodiesel, including methyl myristate, palmitate, methyl palmitoleate, methyl stearate, methyl oleate, and methyl linoleate had been selected as standard materials for FAME analysis using HF-LPME. Physicochemical properties of bio-liquid was measured that the acidity was 3.30 (${\pm}0.01$) and the moisture content was 100.84 (${\pm}3.02$)%. The optimization of HF-LPME method had been investigated by varying the experimental parameters such as extraction solvent, extraction time, stirring speed, and the length of HF at the fixed concentration of NaCl salt. As a result, optimal conditions of HF-LPME for FAMEs were; n-octanol for extraction solvent, 30 min for extraction time, 1200 rpm for stirring speed, 20 mm for the HF length, and 0.5 w/v% for the concentration of NaCl. Validation of HF-LPME was performed with limit of detection (LOD), limit of quantitation (LOQ), dynamic range, reproducibility, and recovery. The results obtained from this study indicated that HF-LPME was suitable for the preconcentration method and the quantitative analysis to characterize FAMEs in bio-liquid generated from food waste via HTC reaction.

• Culinary science and hospitality research
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• v.24 no.2
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• pp.63-70
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• 2018

In this study, the fatty acid content and quality characteristics of the massless enegy treated commercial milk products stored at $30^{\circ}C$ were investigated. The pH of pasteurized milk decreased significantly. UHT milk showed also significant decrease in pH to 4.70~5.72 on the 8th day of storage which was higher than control even there was no significant differences. The acidity of pasteurized milk decreased significantly from the 2nd day of storage to 0.13~0.65% in treatments and control and control was 0.94% at the 8th day of storage and 0.35% in the treatment of ultra high temperature milk. The solid content of pasteurized milk was $7.5^{\circ}Bx$ at 1 day after storage, which showed significant differences from the $11.2^{\circ}Bx$ in the treatment. Pasteurized milk showed more bacterial growth in the treatment than in the control. After 4 days of storage, there was no bacterial count in pasteurized milk but it increased significantly $1.9{\times}10^8$ and $4.5{\times}10^6$ each in UHT milk. Lactic acid bacteria were detected in the curd $2.0{\times}10^6$ in the control and $2.0{\times}10^8$ in the treatment at the 4th day. Palmitic acid content in the saturated fatty acid was the highest at 35.4~41.4% in both pasteurized and ultra high temperature milk. In the UHT milk, linolenic acid was significantly increased to 3.8% in the treatment compared with 2.9% in the control at the 4th day of storage. Therefore, commercial ultra high temperature milk with physical treatment to increase beneficial bacteria showed significant difference compared to the control after 5 days of storage in this experiment.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.706-715
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• 2016

Nutritional composition and physicochemical properties changes in mustard leaf kimchi were investigated during fermentation of up to 3 months. The pH decreased, and the titratable acidity gradually increased according to increase of fermentation periods. Fructose and glucose were the major free sugars in mustard leaf kimchi, and their amounts were significantly decreased with fermentation periods (p<0.05). Lactic acid content showed a significant increase with maximum increase at 3 months. All types of kimchi contained 20 amino acids, but the content of most amino acid fluctuated during fermentation. Except for K and Zn, the content of other ingredients including Ca, Fe, Mg, Na, Se were the highest in kimchi fermented for 2 months. The unsaturated fatty acid of mustard leaf kimchi was higher than that of saturated fatty acid, and total fatty acid of kimchi significantly decreased after 2 months (p<0.05). Most vitamin contents showed a tendency to decrease with fermentation, in particular, vitamin B complex except for $B_2$ significantly decreased after 3 months (p<0.05). The results provide fundamental data for determining the appropriate fermentation period to improve the quality of kimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.990-996
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• 1999

In physicochemical property, increasing the raw materials of Samul Chol Pyon, the content of moisture decreased, somewhat in total sugar, crude lipid, ash was increased. The pH of raw material for Samul Chol Pyon was shown at 5.70~5.80, in the mild acidity. Total saturated fatty acid of 50% added to the sample was shown to be four times higher than that of rice powder. The raw materials of Samul Chol Pyon were shown to possess 16 kinds of total amino acids. The content of minerals, K, P, Zn, Mn, Fe, Mg, Ca increased its additive raw material of Samul Chol Pyon. Especially, Na decreased, while K increased its additive raw materials of Samul Chol Pyon. In a limited Na diet, Samul Chol Pyon should be used in the future.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.5
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• pp.902-910
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• 2015

This study evaluated the qualitative properties of burdock (Arctium lappa L) peels as food material. Proximate composition, sweetness, pH, total acidity, mineral, fatty acid, free sugar, and organic acid contents of preprocessed burdock were measured. Crude ash, protein, fat, and total dietary fiber contents of non-peeled treated lotus roots were higher than those of peeled treated lotus roots (p<0.05). $^{\circ}Bx$, pH, and total acidity were not different in the peeling process. Redness and yellowness of lotus roots were reduced by the peeling process, whereas lightness increased (p<0.05). The mineral contents of Ca, K, Fe, and P were higher in non-peeled lotus roots, whereas non-peeled treated lotus root showed higher K contents (p<0.05). Maltose content was not significantly different, whereas fructose, sucrose and maltose contents were significantly different. Total organic acid contents were higher in non-peeled lotus roots (p<0.01). However total free amino acid contents were higher in peeled lotus roots (p<0.01).