Superiority of traditional cooking process for bugak (Korean traditional fried dish) for plasma lipid reduction

In this study, the efficacy and mode of action of the Korean traditional fried dish bugak for reducing plasma lipids are investigated. Three different studies were performed as follows: lipid-lowering effects of bugak compared with (1) different preparation methods, (2) different batters, and (3) different frying oils. Traditionally, bugak is prepared with fermented glutinous rice batter (FGR) and pan-fried in unroasted sesame oil (USSO; this preparation of bugak is referred to as FGRUSSO). FGR is prepared by placing the glutinous rice and water in a crock for 7 days at room temperature. For the study, wheat flour batter (WF) and soybean oil (SBO) were alternatively used. Low-density lipoprotein receptor knockout (LDLr⁻/⁻) mice (n=24) were fed atherogenic diets with bugak (20 g/100 g of feed) for 10 weeks. Plasma triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) concentration and hepatic lipid accumulations decreased significantly in mice fed FGRUSSO, compared with bugak made with WF and fried in SBO (WFSBO). Protein expression of fatty acid synthesis (FAS) and 3-hydroxyl-3-methylglutaryl coenzyme A reductase (HMGCR) in the FGRUSSO group was decreased, although sterol regulatory element-binding proteins (SREBP-1 and -2) were not different. When batter differences were compared, TG concentration of mice fed bugak prepared with FGR and fried in SBO (FGRSBO) was lower than the WFSBO group due to suppression of hepatic FAS expression. In the oil comparison study, TC and LDL-C concentrations in the FGRUSSO group were lower due to attenuated HMGCR activity. In conclusion, bugak prepared by traditional cooking methods was most effective for lowering plasma TG, TC, and LDL-C via suppressing hepatic FAS and HMGCR activity, although transcription factors for regulating lipogenic enzyme expression were not significantly different.