Bu-Kug Lim

Utilization of waste paper for an environmentally friendly slow-release fertilizer

To help address the physical, chemical, and biological degradation of agricultural soils resulting from indiscriminate use of chemical fertilizers, we developed a slow-release fertilizer from waste paper and urea. This approach has the advantage of a slow-release fertilizer in that it avoids surface runoff or leaching of nutrients, while providing an excellent medium for the recycling of waste paper. The successful impregnation of urea into waste paper was confirmed by scanning electron microscopy. This study also evaluated the release patterns of N from impregnated waste paper using a simulated soil solution and distilled water as leaching solutions. The release patterns of N were examined in both static and continuous-flow conditions for 720 h. Release of N from impregnated waste paper was found to be slow and steady, although the release rate of N was lower in distilled water than soil solution under both conditions.

Effects of manufactured soluble dietary fiber from Quercus mongolica on hepatic HMG-CoA reductase and lipoprotein lipase activities in epididymal adipose tissue of rats fed high cholesterol diets.

This study investigated the effect of a manufactured soluble dietary fiber on lipid metabolism in rats fed high cholesterol diets. Soluble dietary fiber was prepared from wood chips of oak (Quercus mongolica). Male Sprague-Dawley rats weighing 100 +/- 10 g were randomly assigned to either a normal diet or five high cholesterol diets containing 1% cholesterol and different fiber supplements. The high cholesterol groups were subdivided into fiber-free diet (FF), 5% pectin (5P), 10% pectin (10P), 5% manufactured soluble dietary fiber (5QM), and 10% manufactured soluble dietary fiber (10QM) groups. Total serum cholesterol concentrations in all soluble dietary fiber-supplemented groups were lower than in the FF group. The high-density lipoprotein-cholesterol concentration in the FF group was significantly lower, compared with the normal group, but was increased in groups supplemented with soluble dietary fiber. Low-density lipoprotein-cholesterol levels and the atherogenic index had the same tendency as total cholesterol concentration. Compared with the FF group, in the 5P, 5QM, 10P, and 10QM groups hepatic triglyceride concentrations were 12%, 16%, 20%, and 24% lower, respectively, and hepatic cholesterol concentrations were 48%, 52%, 52%, and 58% lower, respectively. Hepatic 3-hydroxy-3-methylglutaryl-CoA reductase activity in the soluble fiber groups was significantly higher than in the FF groups, but lower than the normal group. When hepatic tissue was observed under a light microscope, the FF group had completely formed lipomas in the hepatic tissue, which led to fat deposits and then a fatty liver. The size and number of lipomas were lower in the soluble dietary fiber-fed groups, as compared with the group not fed dietary fiber. In conclusion, improvements in lipid metabolism were observed as a result of the manufactured soluble dietary fiber from the oak chips, and were similar to that seen for pectin. The preparation method for the soluble dietary fiber from oak chips successfully produced a functional soluble fiber.

Physiological Function of Insoluble Dietary Fiber Prepared from Exploded Oak Wood (Quercus mongolica)

This study investigated the production of insoluble dietary fiber using exploded and chemically treated oak wood (Quercus mongolica) and the physiological functions of prepared insoluble dietary fiber in laboratory animals. To produce high quality insoluble dietary fiber, the steam explosion treatment was performed at 25 kgf/cm2 pressure for 6 minutes. In the chemical analysis of insoluble dietary fiber, exploded oak wood was pretreated by 1% sodium hydroxide solution. The insoluble dietary fiber contained 7.6% residual lignin and 61.7% of alpha-cellulose. In order to compare the physiological functions of prepared insoluble dietary fiber with those of commercial insoluble dietary fiber, Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal diet and five high cholesterol diets, containing 1% cholesterol. The high cholesterol diet groups were classified as the fiber-free diet (FF group), 5% commercial alpha-cellulose diet group (5C group), 10% commercial alpha-cellulose group (10C group), 5% insoluble dietary fiber group (5M group) and 10% insoluble dietary fiber group (10M group). Food intake, weight gain and food efficiency ratio in high cholesterol groups were significantly higher than those of the normal group, but there were no significant differences among the high cholesterol diet groups. In addition, there were no significant differences in the weights of liver, kidney and small intestine in insoluble dietary fiber-supplemented groups. Cecum weights in all insoluble dietary fiber groups were significantly higher than those of the FF group. There were no significant differences in the activities of the glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) among the insoluble dietary fiber-supplemented groups. In conclusion, the prepared insoluble dietary fiber and the commercially available insoluble fiber showed the same physiological effects. Moreover, the preparation method for the insoluble dietary fiber from the exploded oak wood was successful.