• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.699-706
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• 2006

The antioxidative and antimicrobial activities of Euphorbia jolkini extracts were investigated. Total polyphenohc compounds extracted were approximately as follows: 162.08 mg/g from ethanol, 12.64 mg/g from n-hexane, 48.11 mg/g from dichloromethane, 544.08 mg/g from ethyl acetate, 176.42 mg/g from butanol, and 30.00 mg/g from water. The ethylacetate fraction of this extraction showed the highest antioxidative activity $(IC_{50})$: DPPH radical scavenging capacity was measured at $8.38\;{\mu}g/mL$, xanthine oxidase inhibitory activity was $466.01\;{\mu}g/mL$, superoxide radical scavenging capacity was $11.39\;{\mu}g/mL$, and nitric oxide scavenging capacity was $332.11\;{\mu}g/mL$. Antimicrobial activities were determined by paper disc method and minimum inhibitory concentration of E. jolkini extracts against food-borne pathogens and spoilage bacteria. The growth inhibition curves of E. jolkini extracts against Bacillus cereus, Listeria monocytogenes, and Escherichia coli were also determined. These results suggest that the ethylacetate fraction of E. jolkini has strong antimicrobial activity against the all species of microorganisms as well as strong antioxidant activity.

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.354-364
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• 1983

Confonmation of (Z)-cinnamonitrile have been studied by molecular orbital theoretically using extended Huckel theory(EHT) and CNDO/2 molecular orbital calculation methods. The results indicate that the stability of conformation is(Z)-gauch>(Z)-planar. The rate constants for alkalie hydrolysis of cinnamonitrile at pH 7.0-14.0 range have been determined by ultra-violet spectrophotometry in 50% methanol at $25^{\circ}C$ and the following rate equation which can be applied over wide pH range was obtained; $${\therefore}k=({\frac{1.41{\times}10^{-14}+1.21{\times}10^7/[H_3O^+]}{2.65{\times}10^{-7}+1.64/[H_3O^+]})+9.14{\times}10^9/[H_3O^+]$$ The rate equation reveals that, at pH 7.0-10.0, the reaction is initiated by the addition of water molecule to unsaturated cabon-carhon double bond of cinnamonitrile and ${\alpha}C-{\beta}C$ bond scission follow subsequently in neutral and alkalie media. At pH 12.0-14.0, in strong alkalie solution, that so-called Michael type nucleophilic addition that the over-all rate constants is only dependent upon the concentration of hydroxide ion occurs competitively and are very complicated. Hence, the reaction mechanism of alkalie hydrolysis of cinnamonitrile which did not carefully before can be fully explained.

• Journal of Dairy Science and Biotechnology
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• v.34 no.2
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• pp.117-135
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• 2016

The present study was performed to develop a functional raw food material from hydrolyzed whey protein powder (23%-GNANA) medication containing sialic acid as a marker compound that is naturally occurring at 7% concentration in GMP (glycomacropeptide). GMP is used worldwide in foodstuffs for babies and infants and is obtained from the milk protein as safe food. While the purpose of our detailed evaluation was aimed to assess preliminary NOAEL values for and above 2,000 mg/kg/day, a clinical dose allowance for 23%-GNANA (as per characteristic of a functional health product, a highly refined test substance of 23% (v/v) sialic acid combined in GMP), at the same time we also wanted to assess the safety of GMP hydrolyzate lacking sialic acid but with identical properties as GMP. Animal safety evaluation was conducted using 23%-GNANA as the test substance, produced from hydrolyzed whey protein powder (product name: HELICOBACTROL-23; provided by Medinutrol Inc. [Korea]; composed of 23% sialic acid and GMP protein) after isolating the sialic acid using enzymes approved as food additives, with GMP as a raw material, and subsequently increasing the content of xx up to 23% through 80% (v/v) ethanol soaking and concentrating, in accordance with GLP Guideline. The animal safety evaluation mentioned above was made on the basis of toxicity in SPF Sprague-Dawley female and male rats dosed with 10 mL of the test substance diluted to 0, 1,250, 2,500, and 5,000 mg/kg directly into their stomachs for 90 d. This was determined in terms of the general symptoms and animal viability, weight and amount of feed intake, eye examination, uracrasia tests, hematological and blood biochemical disorder tests, blood coagulation test, abnormal intestine weight, abnormalities during postmortem and histopathological examinations. Statistical significance was set at P<0.05. Based on the toxicity determination, a certain minor effect associated with the test substance was observed in male rats with no major effects of the tested substance, in comparison with the control group dosed with sterilized water. Nevertheless, the NOAEL value, evaluated as per toxicity criteria, was verified as 5,000 mg/kg/day (P<0.05). Similarly, for female rats, a certain minor effect associated with the test substance was observed in 5,000 mg/kg/day dosed group, with no major effect, yet the NOAEL value (as assessed as per toxicity criteria) was determined to be 5,000 mg/kg/day (P<0.05), which was the same as for male rats. Accordingly, the NOAEL values of the test substances for all female and male rats were finally verified as 5,000 mg/kg/day (P<0.05). In conclusion, it was determined that the 23%-GNANA test substance exceeds 2,000 mg/kg/day, the clinical allowance characteristic for functional health food, and was finally evaluated to cause no safety concerns when used as a raw material in functional health food production, which was the ultimate goal of the present study.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.1-15
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• 2015

Before the advent of pasteurization and other microbiological controls in the dairy industry, milk product-borne diseases such as scarlet fever, typhoid fever, septic sore throat, and tuberculosis were globally widespread. Pasteurization was invented by Louis Pasteur, and it has been considered as one of the most effective ways to control milk product-borne diseases since the 20th century. Nevertheless, till date, various types of cheese in the EU, the USA, and other countries are made from unpasteurized milk as artisan cheese, following the specific food regulations of each nation. Furthermore, after the effectiveness of the Free Trade Agreement (FTA) negotiations between Korea and many nations, the import of various types of cheese made in different conditions and influenced by acidity, preservatives, temperature, competing flora, water activity, and salt concentration increased yearly. Hence, the objective of this review was to describe (1) the 60-day aging rule of cheese, (2) characteristics of the outbreaks linked to cheese manufactured from unpasteurized milk since 1998 to 2011 in USA, and (3) serious health risks from unpasteurized milk, to ensure food protection and safety and to use this basic information for risk assessment.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.693-699
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• 2013

A simple, sensitive, and specific method for quantifying the nicotine content of synthetic favoring substances (SFS) was developed using high performance liquid chromatography (HPLC) with a photo-diode array detector (PDA). Nicotine was extracted from SFS samples by using an acid-base liquid-liquid extraction method with dichloromethane and distilled water. The nicotine content was quantified by HPLC/PDA (261.9 nm) with a $C_{18}$ column under a gradient of 10% acetonitrile with 20 mM ammonium formate (ammonia solution adjusted to pH 8.7) to 100% acetonitrile. The calibration curve, analyzed from concentration standards between 0.1 to 2 mg/L, presented linearity with a correlation coefficient ($r^2$)>0.9999. The limit of quantitation (LOQ) of nicotine in SFS was 0.4 mg/kg, and the average recoveries ranged from 76.4% to 96.3%. The repeatability of measurements, expressed as the coefficient of variation (CV%), ranged from 1.74 to 5.12%. This newly developed method for nicotine quantification in SFS can be considered an analytical method with an acceptable level of sensitivity and repeatability.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.298-309
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• 2001

The purpose of this study was to evaluate the filtering-feeding effect of a freshwater mussel (Corbicula leana) on the phytoplankton communities in two lakes with different trophic conditions between June and September, 2000. Manipulation experiments were conducted with two treatments (the control and mussel addition), and each established in duplicate 10 l chambers. Both ambient nutrient (TN, TP) and chlorophyll-a concentrations were significantly (p<0.01) higher in Lake Ilgam than Lake Soyang. Cyanophytes (Microcystis, Oscillatoria, Lyngbya and Dactylococcopis) consistently dominated algal community in Lake llgam, while flagellated algae (Dinobryon divergence, Mallomonas, Rhodomonas) and cyanophytes (Microcystis)dominated in Lake Soyang. The net exponential death rate ($R\;=\;day^{-1}$) of total phytoplankton in the mussel treatment ranged $1.70{\sim}7.39$ and $0.38{\sim}1.64$ in Lakes Soyang and Ilgam, respectively. Mean filtering rate standardized by mussel AFDW ($ml\;mgAFDW^{1}\;h^{-1}$) was much higher in Lake Soyang ($1.70{\sim}3.06$) than in Lake Ilgam($0.24{\sim}0.88$0.24~o.88). Estimating FR per mussel, 1 mussel filtered $1.6{\sim}7.8\;l$ per day and $1.7{\sim}3.0\;l$ per day in Lakes Soyang and Ilgam, respectively. Based on tile C-flux tobiomass ratio, Corbicula leana consumed $0.8{\sim}4.4$ fold of phytoplankton standing stock in Lake Soyang, and $0.4{\sim}1.6$ fold in Lake Ilgam per day. Mussel feeding resulted in increase of SRP concentration by $30{\sim}50%$, compared with the control. The results of this study suggest that filter-feeding activity of Corbicula leana varies depending on the phytoplankton density and community composition. The high seston consumption rate of Corsicuja Jeaua even in a eutrophic lake suggests that biomanipulation approach using filter-feeding mussels can be used far wate rquality management in small eutrophic reservoirs.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.336-341
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• 2000

This study was conducted to clarify the habitat characteristics and distribution of seagrass. Zostera marina L. (Zosteraceae) in the brackish Hwajinpo Lake, Korea in June 1998 and July 2000. Z. marina beds were distributed along the sea-side cost of the lower lake mouth at 0.8 to 1.5m in death, and the seagrass bed area was about 3,200 m$^{2}$. Salinity, water temperature and pH were in the range of 8.0${\sim}$23.0$%_{o}$, 22.0${\sim}$23.7$^{\circ}C$ and 8.34${\sim}$8.62, respectively. Nutrient concentrations were generally now (TN: 24.34 ${\mu}$M, NH$_{4}$-N: 2.57 ${\mu}$M, NO$_{3}$-N: 0.56 ${\mu}$M, NO$_{2}$-N: 0.27 ${\mu}$M, TP: 2.08 ${\mu}$M, PO$_{4}$-P: 0.34 ${\mu}$M). Suspended particulate matters (SPM) concentration averaged 62.8 mg/l and particulate organic matter (POM) averaged 21.3 mg/l. Organic content of SPM averaged 33.9%. The beds substratum was composed of well-sorted, fine sand and its mean brain size was 3.13${\Phi}$. The Z. marina vegetation was almost submerged, and the morphological characteristics can be classified as steno-leaf phenotype by the shoot length, leaf width, and number of leaf vein. Shoot length and leaf width were 70.0${\sim}$126.5 cm and 5${\sim}$7 mm, respectively. Shoot densities ranged from 264 to 296/m$^{2}$, and the plants biomass was estimated at 332.6 to 373.0 g dw/m$^{2}$. Therefore, the habitats of Z. marina in Korea were recognized in a brackish lake, and morphological characteristics appeared to be variable.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.323-329
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• 2014

The objective of this experiment was to investigate the effect of dietary supplementation of copper-soy proteinate (Cu-SP) and herbal mixture (HBM) on growth performance, blood parameter, and immune response in laying hens. A total 800 Hy-Line Brown laying hens (60 weeks old) were randomly allotted to 1 of 4 dietary treatments : (1) Control : control diet, (2) Cu-SP : control diet + 100 mg/kg Cu-soy proteinate, (3) HBM : control diet + 0.15% herbal mixture, and (4) Cu-SP + HBM : control diet + 100 mg/kg Cu-soy proteinate + 0.15% herbal mixture. Each treatment was replicated 5 times with forty birds units were arranged according to randomized block design. Feeding trial lasted 5 weeks under 16L : 8D lighting regimen. The diet and water were available ad libitum. Result indicated that during feeding trial of the experiment, hen-day egg production was significantly (P<0.05) higher in Cu-SP and HBM treated groups than control. However, feed intake, feed conversion ratio, egg weight, broken and shell less egg production were not significantly influenced by treatments. Eggshell strength was significantly (P<0.05) higher in Cu-SP than control. Eggshell thickness, eggshell color, egg yolk color, Haugh unit were not significantly influenced by treatments. The level of WBC and stress index (heterophil : lymphocyte) were higher in supplemented groups than the control. The concentration of plasma IgG was higher in supplemented groups than the control. The result of this experiment showed that dietary copper-soy proteinate or herbal mixture tended to improve egg production and affect positively on immune response of laying hens.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.1
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• pp.47-55
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• 1999

Applications of chitosan are related to molecular weight and degree of deacetylation(DOD) of chitosan completely. The molecular weight and DOD were greatly affected by the concentration of solution time and temperature. The degree of demineralization was not significantly different at $50^{\circ}C\;and\;70^{\circ}C$ after 30 minutes. Deproteinization decreased as process time increased. The nitrogen content was reached to 6.92% after 90 minute at $80^{\circ}C$, which is similar to theoretical nitrogen content of chitin. The DOD was 82.84% after 2 hours reaction and increased as the reaction time increased in the process. Viscosity and molecular weight are increased as recycling number of concentrated NaOH solution increased. Chemical, biological and physical properties of chitosan depend on the DOD and molecular size of the molecule. Tensile strength of the films from acetic acid solutions was between $28.9{\sim}33.6$ MPa and was generally higher than that of the films from lactic acid. Elongation of the films from lactic acid was between $97.0{\sim}109.7%$ and was generally higher than that of the films from the acetic acid. Water vapor permeability of the films prepared from lcetic acid solutions was between $1.9{\sim}2.3ng{\cdot}m/m^2{\cdot}s{\cdot}Pa$ and was generally higher than that of the films from the acetic acid.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.944-951
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• 2011

An improved cholesterol analysis method was developed for powdered infant formula by gas chromatographic separation after liquid-liquid extraction and partition. In the official Korea Food Standard method for cholesterol analysis, the water phase and solvent phase were not well separated in the case of emulsified foods such as powdered infant formulas and baby foods. For the rapid and simple sample preparation method, an optimized direct saponification condition was established for heating temperature, heating time, and KOH concentration. From the results, the optimum conditions were as follows: heating temperature $90^{\circ}C$, heating time 60 min, and 16 M KOH 10 mL for a 2 g infant formula sample; improved separation condition for gas chromatography was as follows: the initial oven condition was $250^{\circ}C$ for 25 min, the oven temperature was increased to $290^{\circ}C$ by $10^{\circ}C$/min ratio, and finally the oven temperature remained at $290^{\circ}C$for 9 min. The developed method could be implemented for the study of cholesterol, providing the advantages of reduced inspection time and cost in emulsified foods such as infant formula.