Title Page
Abstract
국문 초록
Contents
NOMENCLATURE 14
1. INTRODUCTION 15
2. MATERIALS AND METHODS 18
2.1. Materials 18
2.2. Methods 19
2.2.1. Enrichment of DHA by solvent crystallization 19
2.2.2. Lipase-catalyzed ethanolysis 19
2.2.3. Separation of DHA-enriched fatty acid 20
2.2.4. Preparation of DHA-enriched TAG 20
2.2.5. Analysis of DHA enrichment from solvent crystallization 21
2.2.6. Analysis of DHA enrichment from lipase-catalyzed ethanolysis 22
2.2.7. Analysis of DHA-enriched TAG 23
2.2.8. Statistical analysis 24
3. RESULTS AND DISCUSSION 25
3.1. Enrichment of DHA by solvent crystallization 25
3.1.1. Solvent screening 25
3.1.2. Effect of temperature 29
3.1.3. Effect of fatty acid to solvent ratio 33
3.2. Lipozyme RM IM-catalyzed ethanolysis 36
3.2.1. Effects of temperature 36
3.2.2. Effect of the fatty acid to ethanol ratio 40
3.3. Synthesis of DHA-enriched TAG by Lipozyme 435-catalyzed esterification 44
3.3.1. Effect of temperature 44
3.3.2. Effect of enzyme loading 47
3.3.3. Effect of vacuum 49
3.3.4. Fatty acid composition of DHA-enriched TAG 52
4. CONCLUSION 54
REFERENCES 55
Table 1. Fatty acid compositions (wt%) of the liquid fractions obtained by crystallization with different solvents 27
Table 2. Fatty acid compositions (wt%) of the liquid fractions obtained by crystallization at different temperatures 31
Table 3. Fatty acid compositions (wt%) of the liquid fractions obtained by crystallization at different fatty acid to solvent ratios 34
Table 4. Fatty acid compositions (wt%) of initial tuna oil fatty acid, enrichment I from solvent crystallization, and enrichment II from Lipozyme RM IM-catalyzed ethanolysis 43
Table 5. Fatty acid compositions (wt%)of DHA-enriched triacylglycerols synthesized with DHA-enriched fatty acid and glycerol via Lipozyme 435-catalyzed esterification with different reaction time. 53
Fig. 1. DHA contents and yields in the liquid fractions obtained by crystallization with different solvents. These experiments were carried out at -20℃ with a fatty acid to... 28
Fig. 2. DHA contents and yields in the liquid fractions obtained by crystallization at different temperatures. These experiments were carried out at a fatty acid to solvent... 32
Fig. 3. DHA contents and yields in the liquid fractions obtained by crystallization with different fatty acid to solvent ratio. These experiments were carried out at -40℃... 35
Fig. 4. Effects of temperatures on the DHA content in the fatty acid fractions after Lipozyme RM IM-catalyzed ethanolysis as a function of reaction time. The... 38
Fig. 5. Effects of temperatures on the DHA yield in the fatty acid fractions after Lipozyme RM IM-catalyzed ethanolysis as a function of reaction time. The reaction was... 39
Fig. 6. Effects of fatty acid to ethanol on the DHA content in the fatty acid fractions after Lipozyme RM IM-catalyzed ethanolysis as a function of reaction time. The... 41
Fig. 7. Effects of fatty acid to ethanol on the DHA yield in the fatty acid fractions after Lipozyme RM IM-catalyzed ethanolysis as a function of reaction time. The... 42
Fig. 8. Effects of the temperature on the synthesis of DHA-enriched TAG via Lipozyme 435-catalyzed esterification as a function of reaction time. The reaction was... 46
Fig. 9. Effects of enzyme loading on the synthesis of DHA-enriched TAG via Lipozyme 435-catalyzed esterification as a function of reaction time. The reaction was... 48
Fig. 10. Effects of the vacuum on the synthesis of DHA-enriched TAG via Lipozyme 435- catalyzed esterification as a function of reaction time. The reaction was conducted... 51