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A Study on the Stabilization of Monomeric MDI and Purification of Crude MDI (Crude MDI의 정제 및 Monomeric MDI의 안정화에 관한 연구)

  • Jung, Jong-Won;Kim, Young-Chul;Park, Nam-Cook
    • Applied Chemistry for Engineering
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    • v.7 no.3
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    • pp.588-596
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    • 1996
  • The optimum conditions of the 1st and 2nd distillation had been investigated to obtaine a high quality monomeric MDI and fire reactive polymeric MDI by purification of crude MDI. Effect of additives on the monomeric MDI's color change, dimerization and the reactivity of polymeric MDI with standard polyol system has been tested. When the monomeric MDI yield is approximately 32%, 4,4'-MDI content is above 98% in the monomeric MDI at the 1st distillation. When the separation ratio of initial portion and residue percentage, reflux ratio are set at respectively, approximately 20wt%, 9wt%, above 2 in order to minimize the content of 2,4'-MDI in monomeric MDI, the freezing point of final distilled monomeric MDI is above $38.4^{\circ}C$. Since the monomeric MDI is inherently unstable in the room condition, monomeric MDI easily changes it's color and conducts self-polymerization reaction. To increase the stability of monomeric MDI, the composition of antioxidant, which is composed of phenolic 1st antioxidant, phosphorus 2nd antioxidant, UV absorbent and Hindered amine light stabilizer are used, and benzoyl chloride as antipolymerization agent test are that APHA color is less than 20, dimer content is remained less than 0.36wt% after 45 days storage of monomeric MDI.

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Quality Characteristics of Brown Rice Dasik Prepared with Pollen Powder (화분 분말을 첨가한 현미다식의 품질 특성)

  • Kim, Ae-Jung;Han, Myung-Ryun;Kim, Myung-Hwan;Lee, Soo-Jeong
    • The Korean Journal of Food And Nutrition
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    • v.23 no.2
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    • pp.212-217
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    • 2010
  • To enhance the quality of traditional Dasik, pollen Dasik containing brown rice flour fortified with 5, 10, 15 and 20% pollen powder were prepared, and their physicochemical properties were evaluated. Pollen Dasik possessed higher amount of mineral such as K and Ca than brown rice Dasik. The L value of pollen Dasik decreased with increasing pollen powder compared to brown rice Dasik, while the b value of pollen Dasik was increased with increasing pollen powder compared to brown rice Dasik(p<0.05). Hardness of pollen Dasik decreased with increasing amounts of pollen compared to the brown rice Dasik(p<0.05). Sensory evaluation on pollen Dasik preparewd with over 10% pollen showed the highest sensery evaluation value in overall preference.

Effects of Feeding Dietary Different Oil and Tocopherol on Physico-Chemical Characteristics of Pork (오일과 토코페롤 급여가 돈육의 이화학적 성질에 미치는 영향)

  • 진상근;김일석;송영민;정기화;이성대;하경희;김회윤;박기훈
    • Food Science of Animal Resources
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    • v.23 no.2
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    • pp.115-121
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    • 2003
  • The pork quality was determined with following treatments. The meat samples were obtained from pigs which had been fed finishing pig diets containing 5% beef tallow(Control), 3% beef tallow and 2% perillar seed oil(T1), 250 ppm vitamin E(a-tocopheryl acetate) in T1(T2), 3% beef tallow and 2% squid viscera oil(T3), 250 ppm vitamin E in T3(T4), 3% beef tallow and 2% CLA(Conjugated linoleic acid, T5). T1 had the lowest sarcomere length, salt solubility and total protein contents among the treatments. Salt solubility and total protein content of T2 and T4 which had been fed diets containing Vit. E were higher than those of T1 and T3 which had not been fed diets without Vit. E. pH and water holding capacity(WHC) values of control were higher than those of T1, T3 and T5, while WHC of T2 and T4 was higher than those of T1, T3 and T5. The hunter L value of meat and a value of fat showed higher in T5 than those in control, T, T3. The adhesiveness of T3 and the springiness of T5 in cooked meat showed higher level than other treatments.

Effects of Addition of Mugwort Powder and Carcass Grade on the Quality Characteristics of Pork Patty (쑥 분말 첨가와 도체등급이 돈육 패티(Patty)의 품질에 미치는 영향)

  • 문윤희;강세주;김영길;양종범;정인철;현재석
    • Food Science of Animal Resources
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    • v.23 no.2
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    • pp.97-102
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    • 2003
  • This study was carried out to investigate the effect of addition of mugwort powder and carcass grade on the quality characteristics of pork patty. Pork patties prepared from A patty(grade B pork patty), B patty(grade B pork patty containing mugwort powder), C patty(grade E pork patty) and D patty(grade E pork patty containing mugwort powder). The chemical composition, calorie, residual nitrite, surface color, textural properties, water holding capacity and sensory evaluation were evaluated. Moisture contents(%) were not different among patties, and crude fat(%) and calorie values of patties prepared from grade B pork meat were higher than those of patties prepared from grade E pork meat. Crude ash contents(%) were not different among patties, and residual nitrite contents(ppm) of patties containing mugwort powder were lower than those of patties without mugwort powder. Hunter L and b values of patties prepared from grade B pork meat were higher than those of patties prepared from grade E pork meat, and Hunters a values of patties prepared from grade E pork meat were higher than those of patties prepared from grade B pork meat. Hardness, cohesiveness and chewiness values of patties prepared from grade B pork meat were lower than those of patties prepared from grade E pork meat. Aroma, taste, texture, juiciness, color and palatability values were not different among patties.

Effects of Sugar and Yeast Addition on Red Wine Fermentation Using Campbell Early (가당 및 효모첨가가 Campbell Early 포도주 발효에 미치는 영향)

  • Kim, Jae-Sik;Kim, Sung-Hee;Han, Jung-Sun;Yoon, Byung-Tae;Yook, Cheol
    • Korean Journal of Food Science and Technology
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    • v.31 no.2
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    • pp.516-521
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    • 1999
  • The average sugar content and total acidity (tartaric acid %) in Campbell Early harvested at Youngdong, Chungbuk in 1998 were $11{\sim}16^{\circ}Brix\;and\;0.7{\sim}1.1%$, respectively. Extra sugar should be added to musts to have higher than 12% of alcohol content for red wine fermentation. When extra sugar and active dry yeast were added to Campbell Early must, wine fermentation was ended after 9 days at $25^{\circ}C$. The ethanol content was 14.7% (v/v). However, when sugar was added only without yeast, wine fermentation was ended up at 14. 4% (v/v) of ethanol after 15 days. The total acidity (tartaric acid %) and pH was almost unchanged during both fermentations. Potassium metabisulfite was found to inhibit the propagation of bacteria without affecting red wine fermentation. But when potassium metabisulfite was directly added to young red wine after fermentation, the red color of wine was decolorized to yellow.

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Effects of Gamma Irradiation and Methyl Bromide Fumigation on Quarantine Pest and Physical Quality of Apples (감마선과 methyl bromide 처리가 사과의 검역해충 및 물리적 품질에 미치는 영향)

  • Kang, Ho-Jin;Kwon, Yong-Jung;Byun, Myung-Woo;Kim, Hyun-Ku;Chung, Hun-Sik;Choi, Jong-Uook;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.35 no.5
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    • pp.783-790
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    • 2003
  • Tetranychus urticae Koch and Panonychus ulmi Koch were identified as quarantine pests in apple samples and were controlled soon after the commercial treatment of methyl bromide (MeBr) and with irradiation doses $(0.5{\sim}3kGy)$ after irradiation. The physical qualities of apples, such as rotting, withering, weight changes, hardness, and color, were apparently affected by MeBr. Furthermore, more than 2 kGy irradiation resulted from the lapse of storage time. Associated with the physical qualities of stored apples, irradiation and fumigation for quarantine purposes were more adequate after 40 days of storage at $0{\pm}1^{\circ}C\;(85{\pm}2%\;RH)$ immediately following harvest, rather than soon after harvest. Less than 1 kGy irradiation, based on its accumulated control effect on pests, can potentially be applied as a quarantine procedure without causing significant changes in the physical qualities of fresh apples, in contrast to MeBr.

Effects of Calcium Chloride Concentration and Reaction Time on Physical and Sensory Characteristics of Persimmon Calcium Alginate Beads (염화칼슘 농도와 반응시간에 따른 감 칼슘 알지네이트 비드의 물리적 및 관능적 특성)

  • Yong, Dong-Hee;Song, Min-Kyung;Yoon, Hye-Hyun
    • Culinary science and hospitality research
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    • v.18 no.4
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    • pp.209-221
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    • 2012
  • The purpose of this study is to apply molecular gastronomy and its spherification methodology to persimmon desserts. We prepared persimmon calcium alginate beads and investigated physical and sensory characteristics of beads according to the different concentration of calcium chloride(0.5, 0.75, 1.0%) and reaction time(2, 4, 6, 8, 10 min). Lightness and yellowness were decreased significantly as both calcium chloride concentration and reaction time increased. However, redness was increased significantly as the concentration of calcium chloride and reaction time increased. Hardness, springiness, chewiness, cohesiveness, and resilience except for adhesiveness tended to increase as the concentration of calcium chloride and reaction time increased. The thickness of beads also increased as the concentration of calcium chloride and reaction time increased. Quantitative descriptive analysis showed that voluminosity, springiness, hardness, chewiness, and residue tended to increase as the concentration of calcium chloride increased. Overall acceptability reached a peak at the persimmon bead containing 0.5% calcium chloride. The result of this study showed that the concentration of calcium chloride and reaction time influenced the overall characteristics of calcium alginate beads.

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The Chilling Injury Development and Quality Characteristics of 'Ooishiwase' Plums (Prunus salicina L.) according to Ripening Stages and Cold Storage Temperature (자두 '대석조생'의 숙기 및 저온저장 온도에 따른 저온장해과 발생 및 품질특성)

  • Cho, Mi-Ae;Hong, Yoon-Pyo;Choi, Sun-Young;Jung, Dae-Sung;Lim, Byung-Sun;Park, Soo-Jeong;Lee, Seung-Koo
    • Food Science and Preservation
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    • v.18 no.5
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    • pp.651-660
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    • 2011
  • This study was conducted to evaluate the quality characteristics of and chilling injury development in 'Ooishiwase' plum fruits after harvest, according to the ripening stage and storage temperature. The fruits were harvested at three ripening stages (60, 80, and >90% skin color) and were then stored at 1, 4, 5, 6, and $20^{\circ}C$ cold-storage rooms for up to 48 days. The fruit quality parameters, respiration patterns, and chilling injury development were monitored during the storage periods and the three days of subsequent ripening at $20^{\circ}C$. The fruits harvested at the 60%-skin-color stage maintained the flesh firmness, color, weight loss, and TA, and their respiration rates and ethylene production were decreased compared with the 80%-or >90%-skin-color fruits, at a lower storage temperature. The major symptoms of chilling injuries in the Ooishiwase plums were gel breakdown, flesh browning, and flesh translucency. These symptoms appeared at all the low-storage-temperature and ripening treatment stages. When the fruits, however, were harvested at a more immature stage and were stored at a lower storage temperature, the chilling injury development decreased. These results show that the development of chilling injury in Ooishiwase plums is related to the climacteric behavior during cold storage.

Quality characteristics and antioxidant activity of sponge cake with cabbage powder (양배추 분말을 첨가한 스펀지 케이크의 품질특성 및 항산화 활성)

  • Kim, Sook-Young;Kim, Ki-Ju
    • Food Science and Preservation
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    • v.24 no.2
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    • pp.294-302
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    • 2017
  • The purpose of this study was to investigate the quality characteristics, antioxidant activities and sensory properties of sponge cake with cabbage powder (CP). Physicochemical and sensory properties of sponge cake with different amount (0%, 5%, 10%, and 15%) of CP were examined. As the increase in the amount of CP addition, the specific gravity and baking loss rate were increased, whereas the color of the cake crumb and crust, volume index and specific volume were decreased (p<0.05). The symmetry and uniformity index of the sponge cake were not affected by the addition of CP (5-15%) (p<0.05). The hardness was significantly increased while by CP addition cohesiveness was decreased (p<0.05). The springiness, gumminess and brittleness were not changed by CP addition (p<0.05). The total polyphenolic, DPPH radical scavenging activities and reducing power were significantly increased by addition of CP at high concentrations (p<0.05). In the sensory evaluation, addition of CP significantly degraded the panel preference related to the color, flavor and texture of the sponge cake. However, the highest point were given to sponge cakes containg 5-10% of CP in taste and overall acceptance (p<0.05). These data suggested that adding 5% of CP is the optimal concentration overall for making sponge cake. However, the sponge cake with 10% of CP is recommended in order to maximize antioxidant activity, the sponge cake was the best when contained 5% CP and the sponge cake prepared with the addition of 10% CP was recommended to use due to its advantages in functional property.

Effects of packaging methods on the freshness during storage of lettuce harvested in summer season of Korea (고온기 결구상추의 수확 후 포장조건에 따른 선도유지 효과)

  • Chang, Min-Sun;Lee, Jung-Soo
    • Food Science and Preservation
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    • v.24 no.2
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    • pp.159-167
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    • 2017
  • This study was investigated the effects of maintaining the freshness and stabilization of supply and demand for lettuce (Lactuca sativa L.) by packaging methods in summer. Post-harvest lettuces were packaged by corrugated box, polypropylene (P) box, and individual wrapping using polyvinyl chloride (PVC) film. Then, the lettuce samples were stored at $2^{\circ}C$ and evaluated the change of quality during storage. The lettuces wrapped individually with PVC film had lower weight loss rate, color change, and browning index compared to lettuces packaged by corrugated box and P box. The SPAD value and hardness were higher in lettuces wrapped individually with PVC film than other packaging methods. The lettuces wrapped individually with PVC film were showed the highest total phenolic contents and DPPH radical scavenging activity, but there were no significantly differences by packaging methods. The lettuces packaged by corrugated box were showed the inside browning after 14 days. However, the lettuces wrapped individually with PVC film were showed the best appearance. Therefore, the packaging method of wrapped individually with PVC film were effective in maintaining the freshness during 21 days and helpful for the stabilization of supply and demand for lettuce in summer.