• Title, Summary, Keyword: Physicochemical properties

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Effects of Composts and Soil Amendments on Physicochemical Properties of Soils in Relation to Phytophthora Root and Crown Rot of Bell Pepper

  • Kim, Ki-Deok;Nemec, Stan;Musson, George
    • The Plant Pathology Journal
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    • v.16 no.5
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    • pp.283-285
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    • 2000
  • Two field tests were conducted in 1995 to examine the effects of composts and soil amendments on physicochemical properties of soil in relation to Phytophthora root and crown rot of bell pepper. Chitosan, crab shell waste, humate, sewage sludge-yard trimmings, and wood chips were applied to test plots, some of which affected the levels of P, K, Mg, pH, and H. Physicochemical properties were not related with disease incidence, but percent organic matter, estimated nitrogen release, K, and Mg were correlated with total microbial activity. The elements K and Mg were especially responsible for the increased soil microbial activity that could affect development of root and crown rot of pepper.

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Physicochemical Properties of Freeze Dried Ginseng from the Fresh Ginseng Stored at Low Temperature (저온저장 후 냉동건조한 인삼의 이화학적 특성)

  • 장진규;심기환
    • Journal of Ginseng Research
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    • v.18 no.1
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    • pp.60-65
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    • 1994
  • Fresh ginseng of same grade was stored under the 4$\pm$1$^{\circ}C$ and 87~92% RH for 10 weeks. During the storage, an aliquot amount of the ginseng was drawn, freeze dried and chemical constituents and physicochemical parameters were measured. After 10 weeks of storage drying rate and shrinkage of ginseng were 1520% and 9.04%, respectively, mold growth was seen at week 5 and observed for 51.2% of the ginseng week 10. Amylase activity level was elevated at the early stage of storage and decreased to 5% of initial value at week 5. At week 5, the elevated amylase activity was inconcomitant with the appearance of the mold growth. Crude protein contents were increased and decreased, respectively 5 week post storage. No significant changes in crude fat, crude fiber, ash, total sugar, n-butanol extract and ginsenoside were observed. The content of water-extractable substance showed maximum at week 7 to 8. The value of pH was slightly elevated and reducing sugar was increased during the storage. Key words Ginseng storage, physicochemical properties, drying rate, shrinkage, amylase activity.

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Effects of Ozone Treatment and Gamma Irradiation on the Microbial Decontamination and Physicochemical Properties of Red Pepper Powder (고춧가루의 오염미생물 제거 및 이화확적 특성에 관한 오존처리와 감마선 조사의 영향)

  • 이성희;이현자;변명우
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.3
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    • pp.465-467
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    • 1997
  • The comparative effects of ozone treatment and gamma irradiation on the sterilization, physicochemical properties and sensory quality of red pepper powder were investigated. As for the sterilization of microorganisms, 7.5~10 KGy of gamma irradiation completely eliminated the coliforms, yeast and molds, and total aerobic bacteria. On the other hand, ozone treatment failed to eliminate the highly contaminated microbial load, especially total aerobic bacteria. The physicochemical properties including capsaicin, capsanthin, browning, fatty acid compositions and sensory quality were not significantly changed by gamma irradiation up to 10 kGy, whereas ozone treatment caused significant changes in fatty acid compositions and destruction of natural pigments (p<0.05). The above results led us to conclude that gamma irradiation was more effective than ozone treatment for the sterilization and maintenance of physicochemical and sensory qualities of red pepper powders.

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Physicochemical Properties of Soybeans as Influenced by Storage Temperatures (저장온도가 콩의 이화학적 특성에 미치는 영향)

  • 육홍선;설민숙;이현자
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.5
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    • pp.827-832
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    • 1998
  • Soybeans(Hwangkeum Kong) were stored at 5$^{\circ}C$, $25^{\circ}C$ and 35$^{\circ}C$ for 8 months to investigate the changes of the physicochemical properties. Less physicochemical changes were detected in the soybeans stored at 5$^{\circ}C$ than those stored at $25^{\circ}C$ and 35$^{\circ}C$. High temperature and long term storage caused a decrease in the nitrogen solubility index, whereas increases in acid value and organic acid content were detected. As the storage period was extended at high temperatues, the content of unsaturated fatty acids decreased, but the content of saturated fatty acids increased. Decoloration of soybeans was clearly recognized under high temperatures. The water soluble compoents such as total solids, nitrogen and reducing sugar during water-soaking at 2$0^{\circ}C$ for 16hrs were appreciably eluted from the soybeans stored for 8 months at high temperatures. The pH of the water extract slightly shifted to the acidic range.

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Influence of Ice Recrystallization on Rheological Characteristics of Ice Slurries and Physicochemical Properties of Concentrated Milk

  • Park, Sung-Hee;Kim, Jee-Yeon;Hong, Geun-Pyo;Kwak, Hae-Soo;Min, Sang-Gi
    • Food Science and Biotechnology
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    • v.15 no.5
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    • pp.756-762
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    • 2006
  • Freeze concentration of milk was carried out through the controlled recrystallization of ice in a multi-stage freeze concentrator. Rheological characteristics of ice slurries were analyzed to determine efficient concentration levels for the freeze concentration process. It was determined that efficient concentration level was 17% of total solids in the first and 27% in the second stage. Physicochemical properties were compared between freeze concentrated and evaporated milk. Freeze concentrated milk was more similar in color appearance to control milk than was evaporated milk. pH significantly decreased in evaporated milk than in freeze concentrated milk. pH of freeze concentrated milk resulted in similar value to control. These results indicated the advantages of freeze concentration as a non-thermal milk processing technology in terms of physicochemical properties. Consequently, we investigated the influence of ice recrystallization on the rheological characteristics of ice slurries and physicochemical properties of freeze concentrated milk.

Comparison of the Physicochemical Properties of Freeze-Concentrated versus Evaporated Milk

  • Lee, Su-Jung;Hwang, Ji-Hyun;Kim, Song-Hee;Min, Sang-Gi;Kwak, Hae-Soo
    • Food Science and Biotechnology
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    • v.15 no.6
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    • pp.844-850
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    • 2006
  • This study was designed to compare various quality characteristics, such as nutrient composition and physicochemical and sensory properties of freeze-concentrated milk made by a newly developed continuous multi-stage process with those of evaporated milk. The freeze concentration process reduced the water content up to 73%. Most of the physicochemical properties of evaporated milk were different from raw milk; however the freeze-concentrated milk showed little difference from the raw milk. The thiobarbituric acid value and free fatty acid concentrations were significantly greater in the evaporated milk than in the freeze-concentrated milk. Several effects on sensory characteristics, such as off-taste, were significantly stronger in the evaporated milk. Overall, this study indicates that the newly developed freeze concentration technique results in improved physicochemical and sensory properties, and has little effect on most nutrient levels when compared with the evaporation process. Further research is necessary to further elucidate the chemical and sensory properties of freeze-concentrated milk.

Physicochemical, Microbial, and Sensory Properties of Yogurt with Ulmus davidiana var. japonica During Storage (느릅 분말을 첨가한 요구르트의 이화학적 및 관능적 품질 특성)

  • Ahn, Joungjwa
    • The Korean Journal of Community Living Science
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    • v.25 no.4
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    • pp.601-608
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    • 2014
  • This study evaluates changes in yogurt with Ulmus davidiana var. japonica (U. davidiana) in terms of its physicochemical, microbial, and sensory properties during storage. The pH value and mean microbial counts of this yogurt with 0.2 to 0.8% of U. davidiana added ranged from 4.1 to 4.3 and from $1.4{\times}10^8$ to $2.3{\times}10^8cfu/mL$, respectively, during storage at $7^{\circ}C$ for 16 d. In terms of its color, the L value was significantly higher in the control and U. davidiana yogurt 0.2 to 0.4% up to 4 d, than other yogurt samples, and the b value was influenced by the addition of U. davidiana over 0.6% throughout the storage. According to a sensory test, there was a significant difference in the yellowness score between U. davidiana yogurt and the control, but earthy, and bitterness, and viscosity scores were similar. Overall acceptability was not significantly influenced after 8 d of storage in all yogurt samples, including the control. According to these results, concentrations (0.2 and 0.4%) of U. davidiana yogurt had no significantly adverse effects on its physicochemical, microbial, and sensory properties.

Effect of Sodium Nitrite, Sodium Chloride and Concentrated Seawater on Physicochemical Properties of Meat Emulsion System

  • Lee, Sol-Hee;Kim, Hack-Youn
    • Food Science of Animal Resources
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    • v.40 no.6
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    • pp.980-989
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    • 2020
  • The objective of this study was to compare the effects of various salts on the physicochemical properties of pork emulsion sausages. Pork sausages were prepared using two different salts, sodium nitrite (SN) and sodium chloride (SC), and concentrated seawater (CSW). The CIE L*, CIE a*, and CIE b*, and chroma values of cooked and uncooked sausages with added CSW were significantly higher than those of the sausages with added SC (p<0.05). However, uncooked and cooked sausages with added SN and CSW had similar CIE a* values (p>0.05). The residual NO2- content of sausages with added CSW was significantly lower than that of sausages with added SN. Addition of CSW to sausages resulted in a higher cooking yield compared to the other treatments (p<0.05). Addition of SC resulted in significantly higher volatile basic nitrogen (VBN) and thiobarbituric acid (TBA) values compared to the other treatments. Furthermore, addition of CSW enhanced important physicochemical properties, including CIE a*, CIE b*, residual nitrite content, cooking yield, VBN, TBA, textural properties, and cross-sectional area.

Prediction of Physicochemical Properties of Organic Molecules Using Semi-Empirical Methods

  • Kim, Chan Kyung;Cho, Soo Gyeong;Kim, Chang Kon;Kim, Mi-Ri;Lee, Hai Whang
    • Bulletin of the Korean Chemical Society
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    • v.34 no.4
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    • pp.1043-1046
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    • 2013
  • Prediction of physicochemical properties of organic molecules is an important process in chemistry and chemical engineering. The MSEP approach developed in our lab calculates the molecular surface electrostatic potential (ESP) on van der Waals (vdW) surfaces of molecules. This approach includes geometry optimization and frequency calculation using hybrid density functional theory, B3LYP, at the 6-31G(d) basis set to find minima on the potential energy surface, and is known to give satisfactory QSPR results for various properties of organic molecules. However, this MSEP method is not applicable to screen large database because geometry optimization and frequency calculation require considerable computing time. To develop a fast but yet reliable approach, we have re-examined our previous work on organic molecules using two semi-empirical methods, AM1 and PM3. This new approach can be an efficient protocol in designing new molecules with improved properties.

Effect of ionizing radiation on mechanical and electric properties of polymer composites

  • Soh, Dae-Wha;Kovtunets, V.A.;Kupchishin, A.I.;Mun, G.A.;Nurkeeva, Z.S.;Akhmetkalieva, G.T.;Khutoryanskiy, V.V.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.588-591
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    • 2002
  • Radiation technology is an effective way for regulating polymeric materials to physicochemical and mechanical properties. The effect of radiation on mechanical and electrochemical properties of new rubber-like polymeric composite materials based on poly(vinyl ether of ethyleneglycol : PVEEG) have been studied for investigating mechanical and electric property of polymer composites applications.

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