• Journal of Food Hygiene and Safety
• /
• v.12 no.2
• /
• pp.111-116
• /
• 1997

For the purpose of improving hygienic quality of dried-Angelica Keiskei Koidz powder, the effect of ozone treatment and gamma irradiation on the microbial decontamination and physicochemical properties were investigated. Gamma irradiation at 5 to 7.5 kGy resulted in sterilizing total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the total aerobic bacteria of the sample. The physicochemical properties of the sample were not changed by gamma irradiation up to 7.5 kGy, whereas, ozone treatment caused remarkable changes in pH, TBA value, chlorophyll, carotenoid and fatty acid compositions. Therefore, this investigation demonstrated conclusively that gamma irradiation was more effective than ozone treatment for decontaminating and sterilizing the dried-Angelica Keiskei Koidz powder, with minimal effect on the physicochemical properties analyzed.

• Journal of Biosystems Engineering
• /
• v.23 no.5
• /
• pp.473-480
• /
• 1998

This study was performed to analyze the variation of various physicochemical factors related to the freshness of apple and tomato during post-harvest period. The total soluble solids content, uronic acid content, cell surface roughness. density, rupture deformation and rupture force were measured for 39 days at 7-day intervals for apple and for 11 days at 2-day intervals for tomato. respectively. The cell surface roughness of apple increased with the elapsed time, while the rupture force decreased. In case of tomato, uronic acid content, density and rupture deformation increased with the elapsed time whereas the rupture force decreased. Both apple and tomato exhibited the significant correlations among those physicochemical factors.

• The Plant Pathology Journal
• /
• v.16 no.5
• /
• pp.283-285
• /
• 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.

• Korean journal of food and cookery science
• /
• v.12 no.3
• /
• pp.273-278
• /
• 1996

To investigate the main components of Korean traditional soy sauce for its typical taste, we compare the physicochemical properties of Korean traditional soy sauce and commercial soy sauce. The physicochemical analysis revealed that each components showed significant difference between Korean traditional soy sauce and commercial soy sauce. The significant characters for discrimination between Korean traditional soy sauce and commercial soy sauce were salt content, ammonia nitrogen content and total acidity (R$^2$=0.99). The components of Korean traditional soy sauce divided into 3 clusters, and each group is characterized as formol nitrogen, salt and total nitrogen content by cluster analysis. Main amino acids of Korean traditional soy sauce were alanine, glutamic acid, leucine and valine.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.3
• /
• pp.465-467
• /
• 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.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.4
• /
• pp.585-590
• /
• 1998

To renew interest in Chrysanthemum boreale as a traditional food material, response surface methodology was used for optimizing extraction conditions and monitoring physicochemical properties of ethanol extracts from Chrysanthemum petal. The phenolic compounds of ethanol extracts were minimized in 87ml/g(solvent per sample), 21%(ethanol concentration), and 15 hours(extraction time). The physicochemical properties of ethanol extracts were maximized in the conditions of 115ml/g, 98% and 16 hours on yellow color intensity, 143ml/g, 75% and 19 hours on carotenoid content, and 148ml/g, 53% and 18 hours on soluble solid content. Optimum ranges of extraction condition for physicochemical properties of Chrysanthemum boreale were 130~150ml/g, 70~85% and 20~28 hours, respectively. Predicted values at the optimum extraction condition were in good agreement with experimental values.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.5
• /
• pp.827-832
• /
• 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.

• Journal of Ginseng Research
• /
• v.18 no.1
• /
• pp.60-65
• /
• 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.

• Journal of Applied Biological Chemistry
• /
• v.62 no.4
• /
• pp.407-415
• /
• 2019

The biological half-life of pesticides applied on crops is the key indicator for ensuring the safety of agricultural products. The biological half-life is affected by the several factors like growing conditions of the crop, climate, application method, and physicochemical properties of pesticides. In this study, the biological half-life was calculated and the degradation rates of six triazole fungicides sprayed on perilla leaves were evaluated. Moreover, the statistical analysis confirmed the correlation between the biological half-life and physicochemical properties of six triazole pesticides. The recoveries of the six pesticides were between 84.8-104.9%, which satisfied the residual pesticide analysis criteria. The biological half-life of six pesticides sprayed on perilla leaves, calculated using the first-order kinetics model, ranged between 6.4-15.1 days. When the biological half-life and the physicochemical properties were correlated using the principal component analysis: pKa and Log P, the biological half-life was found to be affected by PC1. The correlation coefficient between biological half-life and physicochemical properties (pKa), calculated by Spearman rank-order correlation, was R² = -0.928 (p <0.01). Biological half-life has been shown to correlate with pKa. In conclusion, it can be used as a database for the relationship between biological half-life and physicochemical properties and will contribute to ensure safe supply of agricultural products.

• Preventive Nutrition and Food Science
• /
• v.10 no.1
• /
• pp.22-28
• /
• 2005

Physicochemical properties and sensory characteristics of kakdugi prepared with red pepper powder gamma-irradiated up to 7 kGy were determined during fermentation at 5℃. The overall fermentation patterns between kakdugies with irradiated and nonirradiated red pepper powder were similar. Kakdugi prepared with irradiated red pepper powder required one week longer time for optimal ripening compared to the kakdugi control. Irradiated red pepper powder did not affect the hardness and fracturability of kakdugi during fermentation. Kakdugi prepared with irradiated red pepper powder maintained a redder color than the kakdugi control. No significant differences were observed in taste, odor, texture, and overall acceptability (p<0.05) except for color. It can be concluded that irradiation of red pepper powder, up to 7 kGy, did not affect the quality of kakdugi with regard to physicochemical and sensory characteristics during fermentation. Moreover, irradiated red pepper powder was better for maintaining the red color and delaying optimum ripening time of kakdugi fermentation.