• Food Science of Animal Resources
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• v.30 no.4
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• pp.674-684
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• 2010

The effects of ascorbic acid (AA) alone or in combination with sodium acetate/calcium lactate (AA+SACL) and chitosan (AA+CH) on the physicochemical properties and microbial growth of beef and pork patties stored at $5^{\circ}C$ were investigated. The patties were case-ready packed in an air-containing polypropylene (PP) tray and sealed with polyethylene terephthlate (PETP)/casted polypropylene (CPP) top film. Treatments with AA, AA+SACL and AA+CH were effective in inhibiting total aerobic bacteria from day 4 compared to the control. In general, thiobarbituric acid, volatile basic nitrogen, and hue values in treated samples were lower than the control over the storage, whereas Hunter ${\alpha}^*$ (redness) values and sensory scores for surface color and off-odor were higher. Regarding quality and shelf-life extension, ground beef and pork patties treated with AA+SACL produced the most desirable results among all treatments during storage.

• The Korean Journal of Zoology
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• v.24 no.4
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• pp.201-215
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• 1981

In vitro intra- and interspecific molecular hybridizations of lactate dehydrogenase isozymes from six species were performed by freezing and thawing the isozymes in sodium chloride, resulting each of the interspecific hybridization of Fluta alba $H_4 \\times$ Ophicephalus argus $M_4$ and that of O. argus $M_4 \\times$ Parasilurus asotus isozymes showed one hybrid isozyme considered to be an $M_2H_2$ isozyme. The results fit with the suggestion that the isozyme of lower vertebrates is a dimer of homodimer as far as te assemblies of subunit M and subunit H are concerned.

• Preventive Nutrition and Food Science
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• v.8 no.3
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• pp.270-277
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• 2003

In order to enhance the firmness and shelf-life of kimchi, as well as to increase the content of well-absorbed digestible calcium, the effect of calcium lactate (CaL) treatment of salted Chinese cabbage on pH, tit ratable acidity, total microbes, lactic acid bacteria, alcohol insoluble substance (AIS) content, firmness, mineral content and tissue structure were investigated. Treatment with the Cal solution increased pH and decreased titratable acidity, which was more pronounced at higher concentrations. The edible period evaluated by pH was 7～8 days for non-treated kimchi, 10 days for 1 % treated kimchi, 15 days for 2% treated kimchi and 20 days for 3% treated kimchi. Total microbes were reduced, but lactic acid bacteria counts were higher in the treated group. CaL treated kimchi showed higher AIS content and firmer texture, which was more conspicuous in the 2 and 3% CaL treated groups. Calcium content in kimchi fermented for 15 days was 40.75～41.53 mg%, which is 42～45% higher than that in the control group. The sodium content was 23～54% less in the treated groups. The epidermis and vascular bundle tissue of kimchi fermented for 15 day was damaged more severely in the control group than in the treated group. CaL treated kimchi has a crispier taste and the development of sour taste was delayed. Therefore, addition of CaL can produces a kimchi with high calcium as well as superior texture and shelf-life, when adjusting the concentration according to the fermentation periods.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.207-214
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• 2009

The purpose of this study was to examine the influence of hypoxic exercise at head down tilt (HDT) on cardiovascular responses. Eight men ($23{\pm}2$ yrs, $176{\pm}4$ cm, and $75{\pm}8$ kg) underwent four separate exercise testing sessions; seated normoxia (SN), seated hypoxia (SH), HDT normoxia (HN), and HDT hypoxia (HH). Each participant performed the leg cycling at predetermined 40% of maximal aerobic capacity relevant to each posture for 15 min. Heart rate was higher in SH than SN and higher also in HH than SH (p<0.05). Blood oxygen saturation was lower in SH than SN (p<0.05). During resting, diastolic blood pressure and mean arterial pressure was significantly lower in HDT than seated posture (p<0.05). No differences were found between conditions in hemoglobin and hematocrit and electrolytes including, sodium, potassium, and chloride. Lactate was higher in SH than SN. In conclusion, there was no effect for cardiovascular responses to duplicate stimuli both hypoxia and posture.

• The Korean Journal of Pharmacology
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• v.10 no.1 s.15
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• pp.55-59
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• 1974

Further elucidation of the mechanism of halothane's negative inotropic action has resulted from a study of the effect of various substrates on halothane-depressed rat atria. Approximately 6 mg% halothane was required to maintain a 50% depression of the contractility of rat atria suspended in a modified Krebs-Ringer bicarbonate glucose medium, pH 7.4, $30^{\circ}C$ for 2hr. Both lactate and acetate were found to restore partially the contractility of halothane-depressed atria. The maximally effective concentration of lactate was 5 mM; for acetate it was 2.5mM. Neither 5 nor 20 mM of additional glucose was effective in restoring the force of contraction of halothane-depressed atria. The results are consistent with the hypothesis that halothane exerts at least a part of its negative inotropic effect on rat atria by inhibiting either the uptake or utilization of glucose by the myocardium. The site of blockade must be prior to the conversion of pyruvate to acetyl CoA. In our previous report dealing with the mechanism of cardiac depressant action of inhalation anesthetic halothane, it has been demonstrated that: 1) approximately 6 mg/100 ml halothane is required to maintain 50% depression of the force of contraction of isolated rat atria in Krebs-Ringer bicarbonate glucose medium; 2) pyruvate partially restores the contractility of halothane-depressed atria, but has no effect on normal atria; the partial recovery of depressed atria by the addition of sodium pyruvate is due to the effect of the pyruvate ion itself, not to the sodium ion; 4) addition of pyruvate, to atria depressed with hypertonic medium, produced only further depression. From these findings we concluded that the cardiac depressant action of halothane on rat atria is a manifestation of inhibition of glucose uptake or utilization. The present studies were undertaken to observe the effect of other substrates on halothane-depressed atria in order to substantiate our conclusion. As with the case of pyruvate, lactate and acetate also partially restored the force of contraction of halothane-depressed atria. These data are consistent with the hypothesis that halothane inhibits glucose uptake or utilization in the glycolytic cycle of the myocardium.

• Journal of Microbiology and Biotechnology
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• v.19 no.7
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• pp.718-726
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• 2009

The objective of this study was to develop and validate secondary models that can predict growth parameters of L. monocytogenes Scott A as a function of concentrations (0-3%) of a commercial potassium lactate (PL) and sodium diacetate (SDA) mixture, pH (5.5-7.0), and temperature (4-37DC). A total of 120 growth curves were fitted to the Baranyi primary model that directly estimates lag time (LT) and specific growth rate (SGR). The effects of the variables on L. monocytogenes Scott A growth kinetics were modeled by response surface analysis using quadratic and cubic polynomial models of the natural logarithm transformation of both LT and SGR. Model performance was evaluated with dependent data and independent data using the prediction bias ($B_f$) and accuracy factors ($A_f$) as well as the acceptable prediction zone method [percentage of relative errors (%RE)]. Comparison of predicted versus observed values of SGR indicated that the cubic model fits better than the quadratic model, particularly at 4 and $10^{\circ}C$. The $B_f$and $A_f$for independent SGR were 1.00 and 1.08 for the cubic model and 1.08 and 1.16 for the quadratic model, respectively. For cubic and quadratic models, the %REs for the independent SGR data were 92.6 and 85.7, respectively. Both quadratic and cubic polynomial models for SGR and LT provided acceptable predictions of L. monocytogenes Scott A growth in the matrix of conditions described in the present study. Model performance can be more accurately evaluated with $B_f$and $A_f$and % RE together.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.52-58
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• 2005

In Korea, little attention has been paid to microbial perchloroethylene (PCE) and/or trichloroethylene (TCE) dechlorination activity and identification of microorganisms involved in PCE reductive dechlorination at a PCE-contaminated aquifer. We performed microcosm tests using the groundwater samples from 4 different contaminated sites (i.e. Changwon A, Changwon B, Bucheon and Yangsan) to assess PCE reductive dechlorination activity. We also adapted molecular techniques to screen what types of known reductive dechlorinators are present at the PCE-contaminated aquifers. In the Changwon A and Changwon B active microcosms where potential electron donors such as sodium propionate, sodium lactate, sodium butyrate, and sodium fumarate, were added, ethylene, an end-product of complete reductive dechlorination of PCE, was detected after a period of 90 days of incubation. In the Bucheon and Yangsan active microcosms, cis-1,2-dichloroethylene (c-DCE) was accumulated without the production of vinyl chloride (VC) and ethylene. Molecular techniques were used to evaluate the microbial community structures in the Changwon B and Yangsan aquifer. We found two sequence types that were closely related to a known PCE to ethylene dechlorinator, named uncultured bacterium clone DCE47, in the Changwon B site clone library. However, in the Yangsan site clone library, no sequence type was closely related to known PCE dechlorinators reported. It is plausible that microorganisms being capable of completely dechlorinating PCE to ethylene may be present in the Changwon B site aquifer. In this study we find that complete PCE reductive dechlorinators are present at some PCE-contaminated sites in Korea. In an engineering point of view this information makes it feasible to apply a biological reductive dechlorination process for remediating PCE- and/or TCE-contaminated aquifers in Korea.

• Food Science of Animal Resources
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• v.29 no.1
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• pp.99-107
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• 2009

The study was performed to evaluate the product quality and shelf-life effect of low-fat comminuted sausages (LFS) manufactured with sodium lactate (SL, 2%), grapefruit seed extract (GSE, 0.2%) and Lentinus edodes (LE) powder (0.25%) alone or in combination. Addition of LE powder lower than 0.25% did not affect the product quality and sensory characteristics (p>0.05). However, LFS containing 2% SL in combined with 0.2% GSE inhibited the growth of inoculated Listeria monocytogenes during refrigerated storage for 8 wk. During refrigerated storage, pH decreased until 2 wk of storage and then increased thereafter. In addition, lightness decreased up to the 1st wk and then increased thereafter. However, redness value was the lowest at 8 wk, and expressible moisture (%) was decreased with increased storage time. Purge loss (%) was gradually increased over 8 wk of storage. Microbial counts of Listeria monocytogenes increased as storage time increased. Based on these results, LFS could be manufactured with LE powder (0.25%) and the addition of SL (2%) in combination with GSE (0.2%) inhibited the growth of Listeria monocytogenes during refrigerated storage of LFS.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.655-666
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• 2005

This study was performed to measure physicochemical and textural characteristics, and shelf-life effect of low-fat functional sausages(LFFSs) manufactured with sodium lactate(SL, 3.3%), lac pigment and various molecular weights(MWs) of chitosan (Low=1.5 kDa, Med=30-50 kDa and High=200 kDa) during storage at 15$^{\circ}C$ for 18 days. LFFSs had 73.7-76.0% moisture, lower than 3% fat and 14-15% protein, respectively. pH values were 6.05-6.44 and the control(150 ppm, $NaNO_2$) was the lowest among LFFSs (p<0.05). Increasing storage time decreased pH values, but no differences in pH values were observed up to 6 days of storage (p>0.05). LFFSs containing SL and low MW of chitosan improved water holding capacity (WHC) and different from those with SL and medium-MW chitosan. WHC was decreased with increased storage time and differences of WHC were observed from 18 days of storage. The addition of chitosan reduced both lightness and redness values, as compared to 150 ppm sodium nitrite(SN), and increased storage time decreased yellowness(p<0.05), especially at 12 days of storage. LFFSs with SL and medium-MW chitosan increased most textural properties compared to the control(p<0.05). The addition of SN of 150 ppm in LFFSs retarded microbial growth for E. coli 0157:H7, while those with SL tended to have an antimicrobial effect for Listeria monocytogenes(LM). The growth rate of LM was delayed by addition of various MW of chitosans in LFFSs, especially high MW chitosan, as compared to LFFSs containing SL alone. These results indicated that the functional, textural and antimicrobial effects of LFFSs were improved by addition SL and various MW of chitosan combinations. In addition, 0.05% lac pigment improved the cure color of LFFSs similar to those of 150 ppm SN.

• Journal of Life Science
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• v.21 no.11
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• pp.1565-1572
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• 2011

Eye-specific lactate dehydrogenase (EC 1.1.1.27, LDH) $C_4$ isozyme in the eyes of greenlings (Hexagrammos otakii) was successfully purified by affinity chromatography and continuous-elution electrophoresis. The molecular weight of the purified eye-specific LDH $C_4$ isozyme was 154.8 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Optimal pH for enzymatic reaction of the eye-specific LDH $C_4$ isozyme was pH 8.5. $K^{PYR}_m$ value of the purified eye-specific LDH $C_4$ isozyme was $1.88{\times}10^{-5}$ M using pyruvate as a substrate. These results indicate that we must consider pH when measuring eye-specific LDH $C_4$ isozyme activity. The eye-specific LDH $C_4$ isozyme had a higher binding affinity for the substrate as a pyruvate than LDH A4 isozyme. Antibodies produced against the purified eye-specific LDH $C_4$ isozyme may be used in the diagnosis of several human diseases and in comparative physiological studies of fishes.