• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.206-214
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• 1990

Effects of commercial food grade porcine pancreatic lipase on the neutral volatile compounds in Cheddar cheese were studied The enzyme was incorporated into the cheese at two different levels of concentration and ripened at various temperatures. The production of 2-butanone increased at higher amount of lipase and higher temperature, but the production of 2-pentanone was inconsistent trends during ripening periods. The concentration of acetaldehyde was the highest among aldehydes and was increased consistently during ripening Periods. In alcohol production ethanol was the most abundant but no further consistent trend was observed after 6 wk. The production of ethyl butyrate was the most abundant ester and related io lipase activities as well as ripening temperatures. Dimethyl sulfide was the only sulfur compound and appeared not to be related to the addition of lipase or ripening temperatures . Statistical analysis suggested that ethyl butyrate was most correlated to aged Cheddar flavor during cheese ripening.

• Journal of Applied Biological Chemistry
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• v.52 no.3
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• pp.151-156
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• 2009

As part of an investigation to identify microorganisms that are biotechnologically interesting for industrial application, we isolated a bacterial strain from Chungkookjang that produces extracellular neutral lipase. In addition, the crude enzyme was characterized. This isolated strain, designated as JKA-3 was identified as Bacillus subtilis JKA-3 based on morphological, physiological and biochemical characteristics, as well as phylogenetic analysis using 16S rRNA gene sequence. The cells were rod-shaped and $0.6-0.8{\times}2.0-2.3\;{\mu}m$ in size. Optimal growth conditions were $35-40^{\circ}C$ and pH 6.0-8.0. The isolate was able to grow in up to 0-10.0% (w/v) NaCl. Optimal activity conditions of the crude lipase fraction of B. subtilis JKA-3 were pH of 7.0 at $35^{\circ}C$. This enzyme was stable in the pH ranging 6.0-8.0.

• Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.16-23
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• 2009

Lipids were extracted from marine rotifer, Brachionus rotundiformis in order to examine the functionality of lipid enzymatic modification. The fatty acids, palmitic, linoleic, oleic and stearic acids were the dominant forms accounting for approximately 35.8%, 21.5%, 15.9% and 7.7% of the total lipid content, respectively. Lipid fractions were categorized as neutral lipids (38.5%), glycolipids (45.9%) and phospholipids (17.6%), and after extraction from the rotifer were isolated by thin-layer chromatography (TLC) as free fatty acids (FFA), monoacylglycerol (MAG), diacylglycerol (DAG) and triacylglycerol (TAG). The production of polyunsaturated fatty acid (PUFA) concentrate from rotifer lipids was studied using lipase-catalyzed hydrolysis. In addition, rotifer lipids were modified by hydrolysis using lipases such as porcine pancreas, Candida rugosa and Rhizomucor miehei. The lipase from Rhizomucor miehei was effective in extracting linoleic acid (C 18:2), while the lipase from Candida rugosa was effective in palmitic acid (C16:0) extraction.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.129-136
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• 2006

Although cleaner and cheaper deinking of ONP could be performed at the neutral or low alkaline condition excessive loss from froth-flotation is unavoidable and so reduction of alkali or caustic soda dosage sacrifices recycling yield. Now the new trade-off regarding alkali dosage versus flotation yield is urgently required in order to set the optimized neutral or low alkaline deinking process of ONP. Lipase from Thermomyces Lanuginosus has an effect on desizing and deacetylation reaction and it could be applied to the stock of pre flotation secondary stage in order to reduce the flotation reject without the sacrifice of optical properties of flotation accepts. Instead of inorganic base, lipase could be applied as a biochemical catalyst for the selective modification of valuable hydrophobic particles in deinking stock, for example cellulose fines and inorganic fillers covered by hydrophobic additives or contaminants. When the enzymatic hydrolysis of ester bond could be made on the surface of hydrophobic particulates, unwanted float of fine particles could be prevented. Now the enhancement of flotation selectivity or the modification of the hydrophobicity of deinking stock is expected to be promoted by the enzymatic pre treatment. And the reduction of recycling cost with the saves of raw material, recovered paper would be possible as a result.

• Food Science of Animal Resources
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• v.41 no.6
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• pp.923-935
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• 2021

Fresh grass carp was used to produce surimi samples that were supplemented with 50 g/kg, 100 g/kg, or 150 g/kg pork back fat. The lipid composition, lipase activity, lipid oxidation index, and lipoxygenase activity of samples subjected to repeated freezethaw process were determined to assess the effects of the added fat on lipolysis and lipid oxidation of grass carp surimi. Freeze-thaw treatment increased free fatty acid content, mainly due to the decomposition of phospholipids and some neutral lipids by lipase. With repeated freeze-thaw treatment, the levels of free fatty acids and phospholipids were correlated with the lipid oxidation indexes and lipoxygenase activity, indicating that lipid degradation can promote lipid oxidation. In the same freeze-thaw cycle, surimi products with high fat content are more vulnerable to oxidative damage, neutral lipids are the main source of free fatty acids in the early stage of freeze-thaw, and phospholipids are the main source of free fatty acids in the late stage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1200-1205
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• 2003

Structured lipids (SL) were synthesized by transesterification of corn oil and conjugated linoleic acid (CLA) in the continuous type reactor using sn-1,3 specific Rhizomucor miehei lipase. The parameters of reaction were observed in terms of flow rate, temperature, and substrate molar ratios. The highest incorporation of CLA was obtained with 1 mL/min flow rate, 55$^{\circ}C$ and 1 : 3 (corn oil/CLA) molar ratio, showing 10.26 ㏖%. When different reaction temperatures and substrate ratios were studied, the highest incorporation was obtained at $65^{\circ}C$ (17.33 ㏖%) and 1 : 5 (corn oil/CLA) ratio (17.50 ㏖%), respectively. After pancreatic lipase analysis, most of all CLA were found at sn-1,3 position. The iodine values of obtained SLs ranged from 110 to 120. From the neutral lipid analysis by normal-phase HPLC, produced SLs composed of 99.35 ∼ 99.89% triacylglycerols, 0.11 ∼ 0.51% 1,2- and 1,3-diacylglycerols, and 0.06 ∼ 0.22% monoacylglycerols.

• Journal of Aquaculture
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• v.22 no.1
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• pp.105-111
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• 2009

In this study, we carried out an experiment for estimation the larval digestibility in aspects which digestive enzymatic activities and nutrition of the rotifers, Brachionus rotundiformis. Thus we enhanced the digestive enzymatic activity through the addition of starch for the increase of digestibility of rotifer (starch-rotifer), and compared with the feed efficiency through rearing of the olive flounder, Paralichthys olivaceus used rotifer lipid-enriched with Algamac $2000^{(R)}$ (CE-rotifer). The digestive enzyme activities (except for TG-lipase), total protein contents, total essential amino acid, essential amino acids (methionin and phenylalanine) of starch-rotifer (the rotifer used a starch as additive, and enriched not) was assayed significantly higher than CE-rotifer (P<0.05). And total lipid, lipid classes (except for sterol) and fatty acids as DHA and EPA showed higher in CE-rotifer than starch-rotifer (P<0.05). But, sterol contents and ST/TG ratio were shown significantly higher in starch-rotifer (P<0.05). The flounder larvae supplied the two rotifers showed standard length and body weight that not significantly differed with ranges $3.72{\sim}3.79\;mm$ and $32.9{\sim}37.8\;mg$/larva on 6 days after hatching (DAH), respectively (P>0.05). However, these of 12 DAH showed the values of significantly higher to $5.94{\pm}0.249\;mm$, $144.0{\pm}23.86\;mg$/larva and $26.2{\pm}12.13%$ in standard length, body weight and survival in CE-flounder than that of starch-flounder (P<0.05). The hydrolytic enzymatic activities of flounder larvae severally supplied the two rotifers showed the significantly higher activities in acidic -amylase, neutral -amylase, TG-lipase, lysozyme and acidic phosphatase in starch-flounder on 5 DAH (P<0.05). But neutral $\alpha$-amylase, three proteases and two phosphatases of CE-flounder on 11 DAH showed the significantly higher activities than that of starch-flounder (P<0.05). Therefore, for the flounder, Paralichthys olivaceus larvae just depleted yolk was more beneficial to supply the feed, rotifer, enhanced the digestibility than to supply the feed lipid-enriched for aspect of larval digestibility up to 6 DAH, thereafter nutrition of absorption due to the development of digestive organs suggested that enrichment effect appeared with larval somatic growth. Consequently, investigation more detailed about the larval digestive physiological and nutritional requirement variations after 6 DAH will be necessary, thereafter.

• Journal of Genetic Medicine
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• v.2 no.2
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• pp.65-70
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• 1998

Lysosomal acid lipase (LAL) plays a central role in the intracellular degradation of neutral lipids derived from plasma lipoproteins. In this study, we investigated the missense mutation within exon 2 of human LAL gene changing of codon -6 of prepeptide from threonine to proline. The Thr-6Pro mutation was detected by the HaeIII restriction fragment length polymorphism (RFLP) and single-strand conformation polymorphism (SSCP). We analyzed the mutation in subjects with 221 unrelated randomly selected control samples and 86 patients with familial hypercholesterolemia (FH) in Korea. We observed that mutation is present with high frequency in Korea compared to other populations studied previously. The frequency of PP homozygote in the FH group was observed considerably higher than that of control. However, there was no significant difference of genotype frequency between two groups. These results, together with the fact that plasma lipids and lipoproteins levels between genotypes showed no statistical difference, suggest that the Thr-6Pro mutation in the LAL gene may have no association with the increased risk of FH development.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.476-481
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• 1994

The lipase activity of crude enzyme extracted from the molded sardine meal(MSM) 'koji', and lipid classes and fatty acid composition of neutral lipid(NL) and phospholipid (PL) of MSM 'koji' were investigated. The optimum pH and temperature of the crude enzyme was 8.0 and $40^{\circ}C$ using olive oil emulsion as a substrate, but the residual activity depended on pH and temperature. Total lipid contents of the MSM 'koji' consisted of 15.33g/100g NL, 5.45g/100g PL respectively. The major lipid classes of NL were triglyceride ($53.4\%$) and free fatty acid($28.1\%$), that of PL were phosphatidylethanol($32.7\%$), phosphatidylinositol($25.5\%$), phosphatidylcholine($25.1\%$), lyso-phosphatidylcholine($7.3\%$) and sphingomyeline($3.5\%$). The prominent fatty acid fractions of NL were 16:0, 22:6, 18:1 n-9, 18:2n-6 and 20:5, with PL fractions the major fatty acid ratios were 22:6, 16:0, 18:1n-9, 18:2n-6 and 20:5, in the same respective order.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.39-41
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• 2011

The recycling rate of recovered paper in Korea is the highest in the world, 92%, but remanufacturing yield is low due to the extremely poor quality of the paper. The poor quality, in turn, influences to the reject amount in deinking process. To increase the yield of old newspaper recycling process, hydrophobic degree of inorganic pigments of deinking stock must be reduced. To determine the hydrophobicity, Pitch Potential Deposit Tester (PDT) was newly designed and applied with respect to the SB latex property of various quality used in Korea; its hydrophobic degree according to Tg, gel content, charge and particle size of latex and optimum designing condition of SB latex. And below are the conclusions: 1. The reason of excessive reject from old newspaper deinking process for total amount of printed ink is loss of inorganic pigments. When lipase, a biochemical catalyst, was applied with the purpose of preventing inorganic pigments loss about more than 70% of total reject weight and promoting hydration of pulp for deinking, deinking process yield of pre flotation secondary stage increased remarkably without any changes of deinking efficiency. 2. Lipase improved deinking stock by cutting ester linkage on surface of hydrophobic materials to promote its hydration. From this, it reached the conclusion that hydration degree of stock exercises significant effect on flotation deinking process yield. 3. Inorganic alkali promotes hydration of deinking stock. But there have been needs for more fundamental measures other than inorganic alkali of promoting hydration for yield improvement. For this, this study intended to find out reasons of chemical properties change on surface of hydrophobic material by change of pH. 4. Pitch Deposit Test (PDT) was performed for understanding principle of why surface of coating flake from OMG is hydrophobic and why it becomes hydrophilic when pH of stock is alkaline. As a result of this test, it is determined that swelling property by change of pH of latex film, which were used as coating adhesive is the reason for hydrophobic change. 5. Hydrophilicity of coating flake increased with hydrophilic pigments. And as more of SB Latex adhesive was used and higher of calcium hardness of stock became, its hydrophilicity decreased. SB Latex adhesive film is reformed by mechanical friction. For having hydrophilicity under neutral pH, strong bruising action such as kneading is required. 6. Because swelling of adhesive film decreases as Tg of SB latex gets lower and mean diameter gets smaller, it shows hydrophobicity under neutral pH. This lowers hydrophilicity of coating flake, which leads to easy elimination with flotation reject on DIP process. Therefore, for improving future flotation yield, it is necessary to develop to use eco-friendly clean SB latex by raising Tg and increasing mean diameter for recycling, and as a result, to reduce excessive loss of coating flake as a reject from deinking process.