Title Page
Contents
ABSTRACT 14
I. INTRODUCTION 17
II. MATERIALS AND METHODS 21
1. Sample preparation 21
1.1. Kimchi preparation 21
1.2. Kimchi methanol extraction 21
2. Physicochemical characteristics of kimchi 22
2.1. Measurement of kimchi pH and acidity 22
2.2. Measurement of kimchi salinity 25
2.3. Measurement of kimchi total aerobic and lactic acid bacteria counts 25
2.4. Kimchi sensory evaluation 25
3. In vivo anti-obesity effects of kimchi 27
3.1. Animal studies 27
3.2. Induction of obesity 27
3.3. Measurement of body weight 28
3.4. Measurement of tissue weight 28
3.5. Serum lipid profiles analysis 30
3.6. Histological analysis of liver and epididymal white adipose tissues 30
3.7. Measurement of mRNA expression levels 30
3.8. Measurement of protein expression levels 33
4. Gut microbiota analysis 34
5. Metabolomic analysis of kimchi samples 36
5.1. Sample preparation for metabolomic analysis 36
5.2. Analysis of kimchi metabolites using UPLC-Q-TOF MS 36
5.3. Data processing 37
6. Statistical analyses 38
III. RESULTS and DISCUSSION 39
1. Physicochemical characteristics of kimchi 39
1.1. pH and acidity 39
1.2. Salinity 41
1.3. Total aerobic and lactic acid bacteria counts 41
1.4. Sensory evaluation 42
2. In vivo anti-obesity effects of kimchi. 46
2.1. Body weight changes and food intake 46
2.2. Tissue weight 50
2.3. Histological analysis of tissues 54
2.4. Lipid profiles of TG, TC, HDL and LDL level in mice serum 58
2.5. mRNA expression levels of epididymal white adipose tissue 63
2.6. Protein expression levels of epididymal white adipose tissue 71
2.7. mRNA expression levels of liver tissue 79
2.8. protein expression levels of liver tissue 83
3. Effects of kimchi treatment on gut microbiota 87
4. Metabolite analysis of kimchi samples using UPLC-Q-TOF MS 91
4.1. Metabolite analysis of kimchi samples 91
4.2. Box plot analysis and relative abundance of identified metabolites of kimchi samples 92
4.3. Heat maps of kimchi metabolites analyzed using UPLC-Q-TOF MS analysis. 93
IV. CONCLUSIONS 101
REFERENCES 105
ABSTRACT IN KOREAN 122
Table 1. Ingredients of kimchi 23
Table 2. Primer sequences of obesity related genes used for... 32
Table 3. Identification of major metabolites contributing the separation among sample groups (LC/MS) 97
Figure 1. A diagram for the preparing of kimchi. 24
Figure 2. Experimental protocols of 45% high fat diet induced obesity in C57BL/6J mice. 29
Figure 3. Change of pH (A) and acidity (B) in various kinds of kimchi fermented at 5℃. 40
Figure 4. Change of salinity in various kinds of kimchi fermented... 43
Figure 5. Changes in total aerobic bacteria (A) and lactic acid bacteria (B) of various kinds of kimchi during fermentation at 5℃ for 4 weeks. 44
Figure 6. Sensory evaluation of various kinds of kimchi fermented... 45
Figure 7. Effects of kimchi on the body weight of high fat diet (HFD)-induced C576L/BJ mice. 48
Figure 8. Effects of kimchi on the food intake of HFD-induced... 49
Figure 9. Effects of kimchi on spleen, kindey and testis weight of... 52
Figure 10. Effects of kimchi on liver and epididymal white adipose... 53
Figure 11. Effects of kimchi on the changes of histological observation of hepatic lipid accumulation in HFD-induced C576L/BJ mice... 55
Figure 12. Effects of kimchi on the changes of histological observation of epididymal white adipose tissues in HFD-induced C576L/BJ... 57
Figure 13. Effects of kimchi on the TG and TC in HFD-induced... 61
Figure 14. Effects of kimchi on the HDL and LDL in HFD-induced... 62
Figure 15. Effect of kimchi on mRNA expression levels of... 64
Figure 16. Effect of kimchi on mRNA expression levels of... 66
Figure 17. Effect of kimchi on mRNA expression levels of... 68
Figure 18. Effect of kimchi on mRNA expression levels of... 70
Figure 19. Effect of kimchi on protein expression levels of... 72
Figure 20. Effect of kimchi on protein expression levels of... 76
Figure 21. Effect of kimchi on protein expression levels of... 77
Figure 22. Effect of kimchi on protein expression levels of... 78
Figure 23. Effect of kimchi on mRNA expression levels of... 81
Figure 24. Effect of kimchi on mRNA expression levels of... 82
Figure 25. Effect of kimchi on protein expression levels of... 85
Figure 26. Effect of kimchi on protein expression levels of... 86
Figure 27. Relative abundance of bacteria at phylum level. 89
Figure 28. Ratio of Bacteroidetes to Firmicutes in fecal samples... 90
Figure 29. Representative LC/MS chromatograms of kimchi. 95
Figure 30. Partial least squares discriminant analysis (PLS-DA) score plots of kimchi (A) analyzed using gas... 96
Figure 31. Box plot analysis of kimchi. 99
Figure 32. Heat maps of kimchi metabolites analyzed using... 100