• Journal of Food Hygiene and Safety
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• v.15 no.2
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• pp.114-121
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• 2000

A study was carried out to establish a detection method for irradiated black and white pepper. Samples were packed in polyethylene bags and irradiated with 2.5, 5, 7.5, 10 and 15 kGy using a Co-60 irradiator. The samples were suspended in water, and alkalized with sodium hydroxide solution. Apparent viscosity was determined after heat gelatinization using a Brookfield DV-III rotation viscometer at 30。C with 30, 60, 90, 120, 150, 180, and 210 rpm. Means and standard deviations of the viscosities of all samples decreased by increasing the stirring speeds. The viscosities increased in all samples by increasing the concentration. Regression expressions and coefficients of viscosity which decreased with increasing irradiation dose of 10% and 13% black pepper, and 7% and 10% white pepper were 0.9531 (y=-131.29x+1,769.0), 0.9725 (y=-351.33x+4,036.0), 0.9731 (y=2,208.0e${^-0.3546X}$), and 0.9959 (y=5,116.0e${^-0.2887X}$), respectively, at 120 rpm. This trend was similar fur all stirring speeds. These results suggest that the detection of irradiated black and white pepper at various doses is possible by the viscometric method.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.641-649
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• 2015

The purpose of this study was to assess the durability of high-strength concrete with high volume mineral admixture (HVMAC) derived from previous studies within ternary blended concrete (TBC) and normal concrete (NC). Four durability evaluation types such as chloride penetration resistance, freezing and thawing resistance, carbonation resistance in two pre-treatment conditions, and sulfuric acid and sulfate resistance using 5% sulfuric acid ($H_2SO_4$), 10% sodium sulfate ($Na_2SO_4$), and 10% magnesium sulfate ($MgSO_4$) solution were selected and performed in this study. HVMAC showed the excellent chloride penetration resistance in any age and the freezing and thawing durability close to 100%. In addition, HVMAC affected more reduction in carbonation resistance than TBC. When the curing time was increased, to create a concrete internal organization densely improved resistance to carbonation. HVMAC also showed the most superior in sulfuric acid and sulfate resistance. As the reduction of calcium hydroxide and $C_3A$ to apply a large amount of admixture reduced the swelling and cracking of concrete, the strength reduction and mass change of concrete was found to be small indicated.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.201-205
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• 1973

In order to eliminate aflatoxin in foodstuffs, the effects of the treatment by various pH conditions, acid and alkali, and salt on each temperature and time were studied in this experiment and the results were as follows: 1) In the low pH, aflatoxins were much more destroyed than high pH. The destruction of aflatoxins was significantly increased by heat in the same pH levels. 2) BY the treatment of 1.5 and 10% of sodium hydroxide and ammonia, aflatoxins were completely eliminated, but $40{\sim}80%$ of aflatoxins were eliminated by the treatment of 1.5 and 10% of acetic acid, hydrochloric acid and sulfuric acid. 3) By the treatment of aflatoxin in bile acid and artificial gastric juice, aflatoxins were completly eliminated and 75% respectively. 4) By the boiling $(100^{\circ}C)$ for 30 minutes in salt solution, $39{\sim}55%$ of aflatoxins was eliminated and no variation was observed as the concentration.

• Journal of Life Science
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• v.19 no.8
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• pp.1033-1038
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• 2009

Maximal productions of gellan by Sphingomnas paucibilis NK2000 from 20 g/l glucose and 10 g/l soybean pomace were 7.46 g/l in a flask and 7.35 g/l in a 7 l bioreactor, when the initial pH of media was 6.8. Maximal production of gellan in a 7 l bioreactor under pH control by sodium hydroxide was 8.42 g/l, whereas that under control by potassium phosphate was 8.50 g/l. The optimal concentration of potassium phosphate in a medium for production of gellan by S. paucibilis NK2000 was found to be 5.0 g/l. Maximal production of gellan in a medium containing 5.0 g/l potassium phosphate without pH control was 8.93 g/l in a 7 l bioreactor. In this study, a simple process without pH control was developed to enhance the production of gellan, with optimized concentration of potassium phosphate in the medium.

• Journal of the Korean Chemical Society
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• v.18 no.5
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• pp.381-388
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• 1974

When mixture of p-phenylenediamine (PPD) and m-aminophenol (MAP) were reacted with formaldehyde (F) varying their amounts under $N_2$ stream at the temperature of -5∼0$^{\circ}$, addition condensation reaction occurred and brown colored resins(in some cases orange colored) were formed immediately. All resins thus formed were insoluble in most ordinary organic solvents and did not melt up to 300$^{\circ}$. When the resins were treated with dilute(7 %) aqueous sodium hydroxide solution, the adsorptivity of methylene blue on them showed marked improvement reaching as much as 80 mg of methylene blue on 1 g of the resin. On the other hand, in the case of bromophenol blue, its amount of adsorption appeared 250 mg per 1 g of the resin. The TGA under $N_2$ atmosphere indicated that the resin formed in molar ratio of 1 : 3 : 8 (PPD : MAP : F) showed the best heat-resistant property among others. About 40 % weight loss was observed for this resin at 900$^{\circ}$ with heating rate of 2$^{\circ}$ per minute.

• Preventive Nutrition and Food Science
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• v.7 no.1
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• pp.78-87
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• 2002

This study investigated the production of insoluble dietary fiber using forest waste and the dietary effect of manufactured insoluble fiber on physiological function in rat fed high cholesterol duets. Insoluble dietary fiber was prepared from the wood chips of oak (Quercus mongolica). The best condition for steam-explosion treatment for the preparation of insonuble dietary fiber was 25 kg/cm$^3$pressure for 6 minutes. In the chemical analysis of insoluble dietary fiber pretreated by 1% sodium hydroxide solution with steam-exploded wood, $\alpha$-cellulose content was 61.7% in the insoluble dietary fiber which contained 7.6% residual lignin. In order to compare insoluble dietary fiber with commercial $\alpha$-cellulose of physiological function, Sprague-Dawley male rats weighing 100$\pm$10 g were randomly assigned to one normal diet and five high cholesterol diet containing 1% cholesterol. The high cholesterol diet groups were classified as fiber free diet (FF group), 5% commercial $\alpha$-cellulose diet (5C group), 10% commercial $\alpha$-cellulose (l0C group), 5% insoluble dietary fiber dict (5M group), and 10% insoluble dietary fiber (10M group). The rats were fed ad libidum for 4 weeks. Food intake, weights gain, and food efficiency ratio in high cholesterol groups were higher than those of normal group, but there were no significant differences between the experimental groups. There were not any significant differences in the weights of livers, kidneys and small intestine of insoluble dietary fiber supplemented groups, but weight of cecum in all insolube dietary fiber group were significantly higher than those of FF group. A gstrointestinal transit time was decreased by supplementation of insoluble dietary fiber. Weight and water contents of feces in the insoluble dietary fiber supplemented groups were significantly higher than those of the FF group. There were not any significant differences in the activities of the glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) between the experimental groups. In conclusion, the manufactured insoluble dietary fiber and commercial insoluble fiber have the same physiological effects. The preparation method of the insoluble dietary fiber from the oak chips suited its purpose.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.71-77
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• 2013

The world demand of renewable bioenergy as an alternative transportation fuel is greatly increasing. Research for bioethanol production is currently being progressed intensively throughout the world. Therefore it will be necessary to develop bioethanol production with cellulosic materials. In this study, the yield of ethanol production was evaluated by simultaneous saccharification and fermentation (SSF) using sodium hydroxide pretreated sorghum ${\times}$ sudangrass hybrids. Composition analysis of 11 varieties of sorghum ${\times}$ sudangrass hybrids was performed for selection of excellent variety to efficiently produce bioethanol. The content of cellulose, hemicellulose, lignin and ash of these varieties were 32~39%, 19~24%, 17~22% and 6~11%, respectively. Among these varieties, 4 varieties of sorghum ${\times}$ sudangrass hybrids were selected for the evaluation of ethanol yield and those were pretreated with 1 M NaOH solution at $150^{\circ}C$ for 30 min using high temperature explosion system. After pretreatment, samples were neutralized with tap water. It contained 52~57% of cellulose. Simultaneous saccharification and fermentation (SSF) was carried out for 48 h at $33^{\circ}C$ by Saccharomyces cerevisiae CHY1011 using Green star variety. The yield of ethanol was 92.4% and the amount of ethanol production was estimated at 6206 L/ha.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.581-587
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• 2022

The leather industry generates a large amount of hazardous leather waste of various types every year. Among them, shaving scrap is difficult to recycle because it contains chromium ions. Many studies in recent years have shown that shaving scraps can be processed into various types of valuable products, such as adsorbent, filler, and poultry feed. In this study, collagen peptides were extracted from shaving scraps and structurally modified to be developed as new materials with improved physicochemical properties. First, the chromium ions contained in the shaving scraps were removed using a sodium hydroxide solution, and purified through concentration and low-temperature crystallization. The purified collagen peptide was used to prepare the powder using a spray dryer. The extracted collagen peptides were structurally modified by introducing double bonds by reacting with methacrylic anhydride (MAA), and the product was confirmed by ¹H NMR spectroscopy. Next, a copolymer was prepared by redox polymerization of the modified collagen peptide (MCP) and 2-ethylhexyl acrylate (2-EHA). The structure of the copolymer was qualitatively confirmed by FT-IR. In conclusion, this study confirmed that collagen peptides can be extracted from shaving scrap and converted into new eco-friendly materials through certain treatments.

• Composites Research
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• v.36 no.1
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• pp.37-41
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• 2023

The treated water inside the ballast electrolytic cell creates a highly alkaline atmosphere due to hydroxide generated at the DSA(Dimension Stable Anode) electrode during electrolysis. In this study, a composite material that can replace the weakness of the PE-coated steel pipe used in the existing ballast pipe was prepared. The test samples are BRE(Basalt fiber reinforced epoxy), BRP(Basalt fiber reinforced unsaturated polyester), GRE(Glass fiber reinforced epoxy), and GRP(Glass fiber reinforced unsaturated polyester). And then it was immersed in NaOH for 720 hours. The friction test of each specimen was conducted. The Friction coefficient analysis according to material friction depth and interfacial adhesion behavior between resin and fiber were analyzed. As a result, the mechanism of interfacial separation between resin and fiber could be analyzed. In the case of the unsaturated polyester resin with low interfacial bonding strength the longer the immersion time in the alkaline solution, the faster the internal deterioration caused by the deterioration that started from the surface, resulting in a decrease in the friction coefficient. It is hoped that this study will help to understand the degradation behavior of composite materials immersed in various chemical solutions such as NaOH, acid, and sodium hypochlorite in the future.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.95-102
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• 2023

Despite the easing of social distancing, demand for non-face-to-face services continues to rise. Recently, the EU is pursuing a comprehensive plastic use reduction by expanding the scope of plastic use regulations for packaging plastics according to the New Cyclical Economy Action Plan(NCEAP). In response to this trend, the packaging industry is moving away from conventional non-degradable/petroleum-based plastics and conducting research on packaging materials using biodegradable plastics such as PLA(Poly Lactic Acid), PBAT(Poly Butylene Adipate-co-butylene Terephthalate). On the other hand, ginkgo leaves occur in large quantities in Korea and act as a cause of slip accidents and flooding. In this study, a method to utilize ginkgo biloba leaf as a new alternative biomass resource was proposed by producing lactic acid through pretreatment, enzymatic saccharification, and fermentation processes. For the efficiency of lactic acid production, a comparative analysis of lignin content from before and after browning was performed. In addition, the degree of glucan extraction was evaluated by applying a pretreatment method using three catalysts: hot water, sulfuric acid, and sodium hydroxide. It is difficult to expect high production of lactic acid with single process. Therefore, an integrated process operation using both the pretreated hydrolyzate and the residual solid enzymatic saccharification solution must necessarily be applied.