• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.699-705
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• 2014

This study was conducted to select the coagulant for konjac processing and to identify the antibacterial activity on foodborn pathogens by concentration of $Ca(OH)_2$. In rheological properties such as hardness, gumminess and chewiness, konjac jelly were increased by progressing coagulation regardless of coagulant. In mineral contents, the Ca content of konjac jelly made with $Ca(OH)_2$ was significantly higher than that of NaOH. On the contrary, the Na content of konjac jelly made with NaOH coagulant was significantly higher than that of $Ca(OH)_2$. There were no significant differences in the Mg and P contents according to coagulant. In sensory evaluation, there were no significant differences in the color, flavor, taste, texture and overall quality according to coagulant. The antimicrobial activities of Staphylococcus aureus, E. coli, Salmonella typhimurium were inhibited in proportion to the concentration of $Ca(OH)_2$. According to the manufacturing process of konjac jelly, the change in microorganism was not found after molding.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.541-546
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• 1992

In order to develop low salt fermented hen clam sauce with high stability, the effects of citric acid pretreatment and fermentation temperature were examined. The VBN contents of surf clam sauce treated with citric acid (SCA) were lower than those of control and the same sauces added alcohol at two temperature conditions ($5^{\circ}C$ and room temperature) during fermentation. The maximum $NH_2-N$ contents of control and SCA during fermentation at $5^{\circ}C$ were 501.3 and $618.4{\sim}691.6\;mg/100g$, respectively, and the pH of those showed $5.61{\sim}6.24$ and $2.43{\sim}3.21$. The total creatine contents of control and SCA, respectively, were $36.8{\sim}27.6\;mg/100g$ ranges. As the time of treatment with citric acid was longer, the degradation of ATP, ADP and AMP in the SCA was faster. In the control, the Ala content was $19.6{\sim}23.02%$ and was highest level among all free amino acids. As fermenting term was longer, among the free amino acids, Ala and Gly were large amounts in control and SCA, respectively, and Gly was slowly increased in SCA during fermentation. As the results of organoleptic test, the tastes of SCA showed good score than control.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.70-78
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• 1989

This experiment was carried out to develop the preparation method of chitosan which has strong antimicrobial activity, and also tried to investigate as a natural food preservative with this chitosan. The antimicrobial activity of chitosan was the strongest when deacetylation of chitin was conducted at $146^{\circ}C$ for 8 hours with $50\%$ sodium hydroxide. The growth of Escherichia coil was completely inhibited by adding this low molecular weight chitosan (M. W, 35,000) at the level of concentration of 75ppm to the medium. The antimicrobial activity was strong enough against such Gram positive bacteria as Staphylococcus sp. and Bacillus sp.. The growth of these strains was inhibited by the concentration of 50ppm but it was varied in its kinds against Gram negative bacteria. The concentration of chitosan re-quired for growth inhibition of microorganisms was 100ppm against Pseudomonas sp. and Vibrio sp., 2,000ppm against Salmonella sp.. The growth of Saccharomyces sp. was inhibited by the concentration of 100ppm, but Hansenula sp., Aspergillus sp., Penicillium sp. and Mu-cor sp. did not inhibited by even more than the concentration of 5,000ppm. The shelf life of Mulkimchi (pickle type Kimchi), containing $0.2\%$ chitosan was 10 days longer than control stored at $5^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.788-793
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• 1999

In this study, it was investigated that the isolation and identification of spoilage bacteria from contaminated aseptic packaged cooked rice, the potential for application of acidic electrolyzed saline solution (AESS) as water-for-cooked rice and the microbiological safety of AESS-based cooked rice. Five strains of Bacillus subtilis and a B. cereus strain among the total six isolates were partially identified by biochemical method and by Microbial Identification System (MIS). The bactericidal effect of AESS was similar as 0.1% NaOCl and 70% ethanol solution, or better than that. All of the test microorganisms except Bacillus spp. that were exposed to AESS for five seconds were destructed. The effect of AESS against Bacillus spp. was much better than that of the two solutions and all of them were destructed or inhibited on exposure for five minutes. The pH value of cooked rice prepared using AESS was in the range of 3.6 to 4.3 and was not almost changed through the storage period. Various concentrations of cell suspension of Bacillus isolates were inoculated to cooked rice, which were prepared with tap water and AESS, and stored at $37^{\circ}C$ for two weeks. The result was shown that the bacteria in tap water-based cooked rice appeared normal cell growth, while they were completely repressed in AESS-based cooked rice.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.63-64
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• 2009

변환시설의 해체 시 발생한 해체폐기물은 2009년 현재까지 약 354톤이며, 이들 중 탱크, 배관, 반응기, 펌프류 동의 해체금속폐기물이 약 191톤으로 54% 를 차지하고 있다. 이들 해체금속폐기물은 제염 처리공정을 통하여 전량 자체처분폐기물로 전환시키는 것을 목표로 두고 있다. 이는 오염된 금속류를 효과적으로 제염한 다음 자체처분시킴으로서 방사성폐기물에 대한 처분비용을 저감할 수 있기 때문이다. 해체금속폐기물 중 스테인레스강 해체폐기물은 질산 용액을 사용한 초음파화학제염공정으로 제염한 후 자체처분폐기물로 53톤을 전환하였다. 탄소강 해체물의 경우 스팀제염공정으로 제염한 결과 제영 효율은 좋았으나 변환시설 가동 중 유지 보수를 위하여 페인팅을 하였던 해체물의 경우 페인트를 제거하지 않을 경우 스팀제염장치로는 제염이 안 되었다. 탄소강 해체금속폐기물은 약 117톤 발생하였으며, 이들 중 모터, 펌프 등을 제외한 제염 대상 폐기물은 약 80톤이며, 이들을 용융 제염 및 감용을 위하여 기초 연구를 수행한 결과를 바탕으로 약 180kg/batch 용량의 금속용융제염 설비를 제작 설치하여 탄소강 해체금속폐기물 용융제염 처리를 수행 중에 있다. 금속용융은 장치가 간단하고 폐기물 처리량이 비교적 적고 단속적인 운전에 매우 효과적인 고주파 유도로를 사용하였다. 용융장치는 고주파 발진장지와 용해로체로 구성된 고주파 유도설비와 냉각계통으로 구성된다. 고주파발진장치는 철제 200kg을 용해할 수 있는 용량을 갖추었으며, 실험 및 실제 처리 등 용해로체의 크기 변경이 필요할 경우에는 고주파발진기의 출력 주파수를 변경할 수 있게 하였다. 용융 장치의 발진기 부분의 입력전원은 3상, 440V, 60Hz 이며, 출력전원은 200kW, 출력주파수는 lkHz, 3kHz, 5kHz로 구성되어 있으며, 회당 180kg 의 폐기물을 용융할 시에는 3kHz로 고정하여 사용하였다. 용해로체 부분 중 고주파유도가열부는 heating coil 및 절연부로 구성되어 있고, 그 외 support frame과 lever로 구성되어 있다. 용해로체와 고주파 발진장치의 냉각을 위한 냉각설비는 냉각기와 냉매의 저장을 위한 저장조로 구성되어 있으며, 냉각기의 용량은 20RT 이다. 용융로체의 직경은 약 28cm로 크기가 큰 해체물의 장입이 어려워 작은 크기로 세절을 해야만 하며，용융로의 용량을 증가시킬 경우 해체물을 작은 크기로 세절하는 비용을 절감할 수 있을 것이다. 용융 중 시료 채취는 매 배치마다 수행하였으며, 그림3과 같은 시료 채취용 주형 틀에 국자모양의 채취기로 채취하였다. 해체물의 용융시 ingot를 생성하기 위해서 주형틀에 용융물을 장입하기 전 시료를 채취하였다 그림4는 생성된 ingot이며, 이들의 방사능 농도는 배치마다 차이는 있지만 최대 0.05 Bq/g 이하로 나타나 자체처분 폐기물로 전량 전환 가능하였다 그림5 는 해체물에 함유된 우라늄과 불순물을 제거한 슬래그로 방사능농도는 약 12Bq/g 으로 나타났으며, 이들의 발생량은 약 3wt% 정도로 폐기물 발생량이 작았다. 따라서 금속폐기물의 경우 용융제염으로 처리할 경우 폐기물 발생량을 최대로 줄일 수 있어 처리 효율이 기타 처리 공정보다 효율적인 것으로 판단된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.139-150
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• 1993

This experiment was carried out to investigate the difference of seed vigor according to seed size, and the physiological aspects and physico-chemical phenomena related with seed vigor in soybean cultivars. Portion of seed coat and radicle to entire seed was much higher in cultivars with small seed than with large. Seed coat rate ranged 7.9% to 9.9%, and radicle 2.5% to 3.3% in small seed group, Whereas in large seed, seed coat rate did 5.5-6.4% and radicle, 1.5 to 2.1%. After accelerated aging treatment, there are significant difference in germination ability between seed size. The germination rate after aging ranged 47 to 80% in cultivars with small seed, but in large seed, only 14 to 24%. After seed was carried out dehydration in incubator at 25 after soaking for 6 hours, the moisture content of seed in drying for 12 hour was 25.5% in small seed, while it was 51% in large seed. Electrical conductivity, leaching soluble nitrogen and sugar content were higher in large seed cultivars. Besides, cotyledon damage after soaking was occurred frequently in large seed cultivars, and seed vigor within same cultivars was higher in small seed than large.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.149-153
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• 1989

Polygalacturonase(PG) and pectinesterase(PE) were extracted from Chinese cabbage and physicochemical properties of the enzymes were characterized. The preheating conditions for maximum retention of Kimchi texture were also studied. The activity of PE was highest at $50^{\circ}C$ and at 0.02M $CaCl_2$ but decreased in 0.2M $CaCl_2$, PG exhibited maximum activity at $65^{\circ}C$ with 0.3mM $CaCl_2$ but was inhibited by $CaCl_2$ at 0.5mM. Both of the enzymes, however, exhibited the maximum activity with 0.25M NaCl. Optimum preheating treatment was determined for minimum PG activity and maximum PE activity. Thus a maximum crispness and firmness was obtained with preheating in 0.05M $CaCl_2$ solution at $50^{\circ}C$ for 1.5hr results indicated that PE activity and calcium ion were very effective in preserving firmness.

• Food Science and Preservation
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• v.18 no.5
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• pp.764-772
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• 2011

Hot-water and 70%-ethanol Smilax china leaf extracts were prepared, and their total polyphenol and flavonoid contents, DPPH-radical-scavenging ability, nitrite-scavenging ability, and antimicrobial activity were determined. The total polyphenol contents of the hot-water and ethanol extract were $5.433{\pm}0.171$ and $13.060{\pm}0.110mg/g$, respectively; their flavonoid contents were $1.599{\pm}0.017$ and $3.005{\pm}0.084mg/g$; their DPPH-radical-scavenging abilities, assayed at 1.0 mg/mL, were 33.6 and 92.3%; and their nitrite-scavenging abilities, assayed at 0.1-2.0 mg/mL, were 37.9-61.6 and 38.4-77.8%. The 70%-ethanol extract showed higher antimicrobial activity than the hot-water extract. The antimicrobial activities were high in Bacillus cereus, Vibrio parahaemolyticus, Salmonella typhymurium, and Staphylococcus aureus, in that order. The antimicrobial substances in the two extracts were maintained after heating at $65-125^{\circ}C$ for 30 min.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.83-89
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• 1986

To investigate effectors on the colloidal stability of whey and soybean proteins, characteristics of tofu-gel formation, effects of heat treatment and salt composition on the colloidal stability, and effects of heat treatment on storage stability were analyzed. When experimental tofus were made from the mixture of whey and soybean, the calcium in the whey precipitated the soy proteins, and disrupted the gel formation, which resulted in the curd of poor texture. In the heat treatment at $60{\sim}100^{\circ}C$, whey and the whey proteins dialyzed against distilled water were readily preciptated at over $70^{\circ}C$, but the mixture of whey and soy extract as well as soy extract were stable at the range of temperature. The proteins of soy extract, whey dialyzed against sodium phosphate buffer, and the mixture were stable at the same heat treatment, and this suggested that phosphates in the soy extract stabilize specialty the whey proteins. Soy proteins were easily destabilized by adding $CaCl_2(0.05{\sim}0.07M)$ at $80{\circ}C$ and $70{\sim}85%$ of the proteins in soy extract and the mixture were preciptated, while only $30{\sim}55%$ of the proteins in whey dialyzed against distilled water were destabilized at the same conditions. Storage stability at $4^{\circ}C$ of the mixture was increased when the mixture was treated at $63^{\circ}C$ and lower temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1475-1483
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• 2006

This study was carried out to examine the optimum processing conditions of seasoned semi-dried oyster, and to investigate its food component characteristics. Three types of semi-dried oyster were prepared: semi-dried oyster prepared without seasoning and coating (C), seasoned semi-dried oyster without coating (S) and seasoned semi-dried oyster coated with alginate (SA). SA was high in moisture (48.6%), while low in lipid (2.8%), and crude protein (25.9%) compared to those of C and S. Hardness and sensory scores of SA were $209.8g/cm^2$ and $3.9\sim4.5$ points, respectively. Total amino acid content (24,299 mg/100 g) of SA was lower than that (27,181 mg/100 g) of C, and the major amino acids were aspartic acid, glutamic acid, leucine and Lysine. The major fatty acids of SA were 16:0 (25.5%) as saturates and EPA (23.5%) and DHA (9.3%) as polyenes. Calcium and phosphorus contents of SA were 42.6 mg/100 g and 245.5 mg/100 g, respectively.