• Microbiology and Biotechnology Letters
• /
• v.13 no.3
• /
• pp.191-198
• /
• 1985

Seven different strains of lactic bacteria and 13 combinations of these microorganisms were tested for their acid forming capacity on a vegetable milk made from lupinseed protein concentrate(LPC). L acidophilus, L casei, S. lactis, L. mesenteroides, mixed culture of L. acidophilus and S. thermophilus, and mixed culture of S. lactis and L. mesenteroides were selected and further tested for their growth pattern and acid forming property on lupinseed milk both untreated and partly hydrolized one with carbohydrate decomposing enzymes. The enzyme hydrolized lupinseed milk had 1.5 folds of total free sugar, 8.2 folds of fructose, 3 folds glucose, 2.3 folds maltose, compared to the untreated lupinseed milk. For the untreated lupinseed milk, L. mesenteroides was appeared to be most suitable microorganism having the maximum cell concentration of 1.0 $\times$ 10$^{9}$ $m\ell$ and the final pH 4.40 with the acidity 0.46％. For the enzyme treated lupinseed milk, mixed culture of L. acidophilus and S. thermophilus showed the best performance having 1.9$\times$10$^{9}$ $m\ell$ maximum cell number and the final pH and acidity were 3.69 and 1.13％, respectively. Lactic acid fermentation altered the physical property of lupinseed milk; by fermentation the viscosity generally increased with untreated lupinseed milk, but decreased with enzyme hydrolized one. The viscosity change and sedimentation rate of fermented milk varied with the type of lactic bacteria. The results of sensory evaluation indicated that S. lactis, L. casei, mixed culture of S. lactis and L. mesenteroides, and mixed culture of L. acidophilus and S. thermophilus, grown on enzyme hydrolized lupinseed milk, could produce acceptable lactic beverage.

• Journal of the Korean Wood Science and Technology
• /
• v.6 no.2
• /
• pp.3-19
• /
• 1978

Five species, Abies koreana Wilson (A. koreana), Castanopsis cuspidata var. Sieboldii Nakai (C. Cuspidata). Machilus thunbergii Sieb. et Zucc. (M. thunbergii), Styrax japonica (S. japonica), and Quercus acuta Thunberg(Q. acuta) growing in the southern part of Korea were selected for the investigation of wood properties. In order to evaluate the wood properties of these five species, anatomical, physical, mechanical, chemical and pulping characteristics were investigated. And this study also covered wood technological problems related to the drying, gluing, debarking, flooring, and wood workability so that these species might serve to the best advantage. The results obtained were summarized as follows: 1. The trunk of A. koreana with many knots was straight. However, the trunks of S. japonica and C. cuspidata were crooked. 2. A. koreana showed the longest and the widest ill the fiber morphology; 2.97mm in length, 39.3${\mu}$ in width. In general, fiber width of all the species investigated were greater than those of other Korean hardwoods. 3. The specific gravity of Q. acuta was 0.74${\pm}$0.03, and that of A.koreana was 0.34${\pm}$0.02. The range of specific gravity of the other species was 0.47-0.52. 4. The adsorption of water was propotioned inversely with the specific gravity, but the adsorption of humidity was proportioned with the specific gravity. In spite of their medium density, S. japonica showed the greatest adsorption, and M. thunbergii the least. The water adsorption of cross section was twice greater than that of lateral direction, and there was a slight difference in between the radial and the tangential direction. 5. Shrinkage for tested five species was ranged from 5.36 to 10.24% in tangential direction, and 2.83~6.13% in radial direction. Q. acuta recorded the greatest shrinkage rate, and A. koreana the least. The greater was the specific gravity, the larger was the shrinkage rate. 6. The mechanical properties of Q. acuta were similar to those of Quercus mongolica which grow in Kangwon-Do. Strength properties of C. cuspidata, M. thunbergii, A. koreana were equivalent to those of other Korean commercial woods with similar specific gravity, except S. japonica which showed slightly higher strength than that of other species with similar density. 7. Higher glue joint strength for urea and phenol adhesieves was recorded in the species of M. thunbergii and C. cuspidata, however, high-density species(Q. acuta) and even low-density species(A. koreana) did not show good joint strength. 8. The attractive figure of M. thunbergii in texture seemed to he appreciated for decoration. And the grain and texture of other species were proper for furniture and building materials. 9. All of the species except Q. acuta were considered good for wood workability. 10. The denser the specific gravity was, the longer the drying time took. However, severe drying defects were formed in M. thunbergii whose density was medium. 11. All the species were considered suitable for the flooring wood expect A. koreana whose density was light. 12. Pentosan component in all the species was great, and the amount of extractives in Q. acuta was worth noticing. 13. Yield in kraft pulp was above the level of economic pulp yield, i.e. 45% in all species. 14. Debarking was easy in the species of A. koreana and M. thunbergii, and debarking after being boiled in water was the most efficient in all species.

• Journal of the Korean Wood Science and Technology
• /
• v.16 no.2
• /
• pp.1-41
• /
• 1988

For the purpose of utilizing the sawdust having poor combining properties as board raw material and resulting in dimensional instability of board, polypropylene chip (abbreviated below as PP chip) or oriented PP thread was combined with sawdust particle from white meranti(Shorea sp.). The PP chip was prepared from PP thread in length of 0.25, 0.5, 1.0 and 1.5 cm for conventional blending application. Thereafter, the PP chip cut as above was combined with the sawdust particle by 3, 6, 9, 12 and 15% on the weight basis of board. Oriented PP threads were aligned with spacing of 0.5, 1.0 and 1.5cm along transverse direction of board. The physical and mechanical properties on one, two and three layer boards manufactured with the above combining conditions were investigated. The conclusions obtained at this study were summarized as follows: 1. In thickness swelling, all one layer boards combined with PP chips showed lower values than control sawdustboard, and gradually clear decreasing tendendy with the increase of PP chip composition. Two layer board showed higher swelling value than one layer board, but the majority of boards lower values than control sawdustboard. All three layer boards showed lower swelling values than control sawdustboard. 2. In the PP chip and oriented thread combining board, the swelling values of boards combining 0.5cm spacing oriented thread with 1.0 or 1.5cm long PP chip in 12 and 15% by board weight were much lower than the lowest of one or three layer. 3. In specific gravity of 0.51, modulus of rupture of one layer board combined with 3% PP chip showed higher value than control sawdustboard. However, moduli of rupture of the boards with every PP chip composition did not exceed 80kgf/cm2, the low limit value of type 100 board, Korean Industrial Standard KS F 3104 Particleboards. Moduli of rupture of 6%, 1.5cm-long and 3% PP chip combined boards in specific gravity of 0.63 as well as PP chip combined board in specific gravity of 0.72 exceeded 80kgf/$cm^2$ on KS F 3104. Two layer boards combined with every PI' chip composition showed lower values than control sawdustboard and one layer board. Three layer boards combined with.1.5cm long PP chip in 3, 6 and 9% combination level showed higher values than control sawdustboard, and exceeded 80kgf/$cm^2$ on KS F 3104. 4. In modulus of rupture of PP thread oriented sawdustboard, 0.5cm spacing oriented board showed the highest value, and 1.0 and 1.5cm spacing oriented boards lower values than the 0.5cm. However, all PP thread oriented sawdustboards showed higher values than control saw-dustboard. 5. Moduli of rupture in the majority of PP chip and oriented thread combining boards were higher than 80kgf/$cm^2$ on KS F 3104. Moduli of rupture in the boards combining longer PP chip with narrower 0.5cm spacing oriented thread showed high values. In accordance with the spacing increase of oriented thread, moduli of rupture in the PP chip and oriented thread combining boards showed increasing tendency compared with oriented sawdustboard. 6. Moduli of elasticity in one, two and three layer boards were lower than those of control sawdustboard, however, moduli of elasticity of oriented sawdustboards with 0.5, 1.0 and 1.5cm spacing increased 20, 18 and 10% compared with control sawdustboard, respectively. 7. Moduli of elasticity in the majority of PP chip and oriented thread combining boards in 0.5, 1.0 and 1.5cm oriented spacing showed much higher values than control sawdustboard. On the whole, moduli of elasticity in the oriented boards combined with 9% or less combination level and 0.5cm or more length of PP chip showed higher values than oriented sawdustboard. The increasing effect on modulus of elasticity was shown by the PP chip composition in oriented board with narrow spacing. 8. Internal bond strengths of all one layer PP chip combined boards showed lower values than control sawdust board, however, the PP chip combined boards in specific gravity of 0.63 and 0.72 exceeded 1.5kgf/$cm^2$, the low limit value of type 100 board and 3kgf/$cm^2$, type 200 board on KS F 3104, respectively. And also most of all two, three layer-and oriented boards exceeded 3kgf/$cm^2$ on KS F. 9. In general, screw holding strength of one layer board combined with PP chip showed lower value than control sawdustboard, however, that of two or three layer board combined with PP chip did no decreased tendency, and even screw holding strength with the increase of PP chip composition. In the PP chip and oriented PP thread combining boards, most of the boards showed higher values than control sawdustboard in 9% or less PP chip composition.

• Korean Journal of Agricultural Science
• /
• v.18 no.2
• /
• pp.140-147
• /
• 1991

This paper was performed to obtain the data applied to use of synthetic lightweight aggregate concrete affected by alkali silica reaction. The results obtained were summarized as follows : 1. The expansion of each type concrete was increased with increase of curing age, respectively. Also, at the curing age 90 days, the rate of expansion of type A, B, C and D concrete was increased 0.173%, 0.575%, 0.230% and 0.680%, respectively. Specially, the rate of expansion of type D concrete was shown 3.93 times higher than the type A concrete. The cracks width were increased with increase of expansion and at the 0.680% expansion, the maximum width was shown 0.5 mm. 2. The dynamic modulus of elasticity of each type concrete was increased with increase of curing age, respectively. At the curing age 30 days, the highest dynamic modulus of elasticity was showed at each type concrete, respectively. But, it was gradually decreased with increase of curing age at those concrete, respectively. Also, at the curing age A, B, C and D concrete was increased 24.3%, 33.7%, 28.1% and 37.0%, respectively. The rate of loss in type D concrete was shown 1.52 times higher than the type A concrete. 3. The ultrasonic pulse velocity of each type concrete was increased with increase of curing age, respectively. At the curing age 30 days, the highest ultrasonic pulse velocity was showed at each type concrete, respectively. But, it was gradually decreased with increase of curing age at those concrete, respectively. Also, at the curing age 90 days, the percentage loss of ultrasonic pulse velocity of type A, B, C and D concrete was increased 6.4%, 8.7%, 8.5% and 14.2%, respectively. The rate of loss in type D concrete was shown 2.21 times higher than the type A concrete. 4. The relation between dynamic modulus of elasticity and ultrasonic pulse velocity was highly significant. The dynamic modulus of elasticity was increased with increase and decreased with decrease of ultrasonic pulse velocity. Also, the decreasing rate of the dynamic modulus of elasticity was shown 2-7 times higher than the ultrasonic pulse velocity at each age, respectively. 5. The dynamic modulus of elasticity and ultrasonic pulse velocity were decreased with increase of expansion, and the decreasing rates were increased with increase of curing age. The increasing rate of expansion was shown higher than the decreasing rate of dynamic modulus and ultrasonic pulse velocity.

• Korean Journal of Agricultural Science
• /
• v.13 no.2
• /
• pp.227-242
• /
• 1986

This paper describes the observed behavior in the direct shear test on decomposed granite soil having the complicate engineering properties at various different levels of factors. The objectives of this study were to investigate the characteristics of the decomposed granite soil under controlled various moisture content, dry density, strain rate and soaking which give influence to the shear strength. The results were summarized as follows; 1. The shear strength was decreased remarkably with the increasing of moisture contents of A and B soil were 5-10% and 15-20% respectively. 2. Cohesion and angle of internal friction were decreased with the increasing of moisture content and increased with the increasing of dry density. 3. The shear strength was increased with the increasing of normal stress and volume change was decreased on the whole. The shear strength was generally increased with the increasing of the strain rate. 4. As dry density increases, A-soil shows the progressive failure and the decrease of volume change while B-soil shows the initial failure and the increase of volume change. 5. The relationships between the soaked and unsoaked specimens were as follows ; ${\tau}_f=0.1009+1.026{{\tau}_f}^*$ (A-soil), ${\tau}_f=0.1586+0.8005{{\tau}_f}^*$ (B-soil) 6. Angle of internal friction of the direct shear test shows larger value than that of the triaxial compression test. All effective stress path was nearly similar.

• Microbiology and Biotechnology Letters
• /
• v.26 no.4
• /
• pp.275-282
• /
• 1998

To investigate the increased acid tolerance of a acid-resistant mutant Leuconostoc paramesenteroides P-100 improved as a kimchi starter, proton permeability, ATPase acitivity, glycolysis activity, $Mg^2$sup +/ releasement, and membrane fatty acid composition were studied and comprised with its wild type Leuconostoc paramesenteroides Pw. In the proton permeability experiment, the maximum values of the average half time (t$\_$1/2/) of pH equilibration through the cell membrane of the Pw and the P-100 were about 6.4 min and 7.8 min in 150 mM KCI solution, respectively. In the 3% NaCl solution, the t$\_$1/2/ values of the Pw and the P-100 were 5.5 min and 6.9 min, respectively. The values and pHs of maximal specific activities of ATPase originated from the Pw and the P-100 were 0.5 unit/mg protein and 0.78 unit/mg protein at pH 6.0, respectively. The result of pH dependence of glycolysis showed that the P-100 had higher activities than that of Pw except at pH 7.0. The releases of magnesium from the Pw and the P-100 were observed about 54.5% and 23.2% at pH 4.0 after 2 hours, respectively. The results of comparison of membrane fatty acid composition of the Pw with the P-100 showed that C$\_$8:0/, C$\_$9:0/, C$\_$10:0/, C$\_$11:0/, C$\_$18:0/, and C$\_$19:0,cyclo/ were major different fatty acids between two strains and the content of C$\_$18:1/, and C$\_$19:0,cyclo/ were 2.8%, N.D (not detected) in the Pw and 0.4%, 2.3% in the P-100. These results indicated that acid tolerance of the P-100 was significantly improved in comparison with its wild type Pw.

• Microbiology and Biotechnology Letters
• /
• v.38 no.2
• /
• pp.177-182
• /
• 2010

The goal of this study was to characterize the quality and physiological functionality of some traditional rice wines in Chungnam province, Korea. Non-sterilized and commercial sterilized traditional rice wines from five traditional rice wine factories of Chungnam province were collected and investigated for nutritional components, noxious compounds and physiological functionality. Ethanol content ranged from 16.1~18.3% and pH ranged from 3.27~4.76, and they also contained 0.15% to 0.55% of total acid. All traditional rice wines contained 10.15~139.9 mg% of amino nitrogen and 2.5~25.7% of total sugar. Among organic acids, lactic acid was contained 7.4~29.6 mg%, and succinic acid and propionic acid was also contained 0.2~2.7 mg% and 0.7~8.3 mg%, respectively. Antihypertensive angiotensin I-converting enzyme inhibitory activity were showed 37.0~86.0% in all rice wines, however, fibrinolytic activity, antioxidant activity, SOD-like activity and acetylcholinesterase inhibitory activity were low or not detected.

• Journal of the Korean Wood Science and Technology
• /
• v.10 no.3
• /
• pp.118-131
• /
• 1982

1. In order to investigate the effect of variation of assembly time on glue bond strength, and to determine the optimum range of assembly time with given glue, this experiment was made at the suggestion of the Wood Technology Laboratory, School of Forestry, Yale University. 2. For this investigation, three-ply-plywoods with 1/22 inch, birch veneer, phenolic resin, and soybean glue were made at the following variation of assembly time, that is, 1, 5, 10, 25, 35, 50, and 70 minutes, under both open and closed assembly manners, and the shear strength test at dry and wet were adoptted. 3. The shear strength and wood failure of each plywood panel constructed at the given assembly time have been illustrated in Tables 1, 2, 3 and 4. It has shown that there is a remarkable tendency, for increasing assembly time to give lower shear strength and wood failure throughout almost all cases. The effective range of assembly time of tested glues in this investigation for both open and closed assembly are summarized in the Table 7. Thus, allowable assembly time for Phenolic resin may be up to 10 minutes under open assembly and up to 50 minutes under closed assembly. For soybean glue, the permissible assembly time may be up to 5 minutes under open assembly and up to 15 minutes under closed assembly. The allowable assembly time for open assembly with the same glue is reduced by approximately one third or more than one third as compared with closed assembly time. This might mean that the closed asembly time for these glues is more practical than the open assembly.

• Journal of the Korean Wood Science and Technology
• /
• v.12 no.2
• /
• pp.20-26
• /
• 1984

This study was carried out to investigate the influence of chemical type and its retention in the fire-retardant treated plywoods on the static bending strength, a property peculiar to plywood. Being soaked in 20% aqueous solution of $(NH_4)_2SO_4$, $NH_4H_2PO_4$, $(NH_4)_2HPO_4$. Borax-Boric acid and Minalith for 3 to 12 hours at three-hour intervals and redried at $120^{\circ}C$ in hot press, the treated plywoods were put to static bending test. The values of chemical treated plywoods in Stress at proportional limit, Modulus of elasticity, Modulus of rupture and Work per unit volume to proportional limit were widely higher than those of water treated plywoods(control) and Borax-Boric acid treatment showed the highest value in the four mechanical data. And the bending strength of fire-retardant treated plywoods increased with the extension of soaking time or the increase of chemical retention in themselves. Borix-Boric acid was the desirable fire-retardant for thin plywood in view of mechanical strength and soaking defects in this study.

• Journal of the Korean Wood Science and Technology
• /
• v.36 no.3
• /
• pp.30-38
• /
• 2008

Petroleum-based resin adhesives have extensively been used for the production of wood panels. However, with the increase of manufacturing cost and the environmental issue, such as the emission of volatile organic compounds, of the adhesive resins, it is necessary to be developed new adhesive systems. In this study, the potential of okara, which is a residue wasted from the production of tofu, for the development of bio-based adhesives was investigated. At first, the physical and chemical properties of okara were examined. After okara was hydrolyzed in acidic and/or alkaline solutions, okara-based adhesive resins were formulated with the mixtures of the okara hydrolyzates and phenol formaldehyde (PF) prepolymer. The adhesive resins were used for the fabrication of plywood panels, and then the adhesive strength and formaldehyde emission of the plywood panels were measured to examine the applicability of the resin adhesives for the production of plywood panels. The solids content and pH of the okara used in this study were around 20% and weak acidic state, respectively. In the analysis of its chemical composition, the content of carbohydrate was the highest, and followed by protein. The shear strengths of plywood fabricated with okara-based resin adhesives exceeded a minimum requirement of KS standard for ordinary plywood, but its wood failure did not reach the minimum requirement. In addition, the formaldehyde emissions of all plywood panels were higher than that of E1 specified in the KS standard. Based on these results, okara has the potential to be used as a raw material of environmentally friendly adhesive resin systems for the production of wood panels, but further researches - biological hydrolysis of okara and various formulations of PF prepolymer - are required to improve the adhesive strength and formaldehyde emission of okara-based resin adhesives.