• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.314-319
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• 1997

The objectives of this study were to examine the effect of storage time, temperature, pH, and NaCl concentration on hydroperoxide lyase and lipoxygenase activities, and to establish important informations to the production of typical cucumber flavor. Conditions affecting lipoxygenase and hydroperoxide lyase would be important for cucumber flavor production. Maximum activity was observed at pH 5.0 for hydroperoxide lyase and pH 5.5 for lipoxygenase. Both enzymes were relatively stable at $40\;to\;50^{\circ}C$ for 6days storage time. Maximum activity of both enzymes was observed with 0.2 M NaCl at pH 5.0. Activities were stimulated with concentrations of NaCl from 0.05 to 0.2 M. Hydroperoxide lyase and lipoxygenase activities were decreased at concentration of NaCl greater than 0.2 M.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.733-739
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• 1994

To extend the self-life of Dooboo (tofu), fish paste and Makkoli (Korean traditional rice wine) for which severe heat treatment are not expectable, main putrefactive microorganisms were isolated from each product and tested their growth inhibition by ethanol and water extracts of several edible plants. The ethanol extract of Phellodandron amurense Ruprs had the strong effect of growth inhibiting to all three isolates from Dooboo and Makkoli, and Eugenia caryophyllus, Pinus rigia Mill, Bletilla striata (Thunb) Reichb. Fill and Paeonia albiflora Pall were also same effect to isolates from fish paste. The ethanol extract was more effective inhibiting than water extract in all test microorganisms. The evident inhibition level of each extract was 2000 ppm of Pa ethanol for fish paste and 1000 ppm for Makkoli.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.40-44
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• 1988

This paper was carried out to investigate the relation of pH, aciidity and sourness during Kimchi fermentation and preservatives on Kimchi fermentation. Na-acetate, Na-malate, K-sorbate and K-sorbate+acetic acid were added to Kimchi samples. These Kimchi samples were fomented for 7 days at $37^{\circ}C$ and $20^{\circ}C$. In the experiment about the sourness and buffer action by organic salts which showed that the intensity of sourness was differented by the difference of pH in the same acidity. Na-acetate (0.3%) and Na-malate (0.3%) acted as good buffer, whereas K-sorbate (0.1%) and K-sorbate (0.1%)+acetic acid (0.05%) acted as lactobacilli growth enhancer in the fermentation.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.266-271
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• 1993

In order to investigate the traditional value of Ewhaju (traditional wine) and to establish the brewing condition, studies on of traditional background and field inquiry were carried out. Scientific evaluation and possibility of revealation of Ewhaju were searched by the experiments of microbial and enzymatic properties of brewed Ewhaju and Nuruk by traditional method. In flora of microorganisms in Nuruk of Ewhaju, Aspergillus oryzae and Hansenula sP. were isolated, and, showed a level of 1.2$\times$$10^6$ CHU/g, respectiveln but other microorganisms were not grown in diluted cultivation test. The a-and f-amylase activity of Nuruk were 30.74 and 34.4, respectively and their activities of two amylases were 19.28 and 18.8 at first stage of brewing, 21.21 and 19.80 at 100 day after brewing, and 20.25 and 19.90 at one year aged Ewhaju, respectively. The brewed Ewhaju could be remained with high quality long period without teat treatment or addition of preservatives, also, stored Ewhaju contains remarka-bly high activity of amylases which might contribute to digestion.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.428-439
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• 1992

Drying process in a fixed bed red pepper dryer was modeled and simulated. Drying efficiency describing the effectiveness of energy usage in red pepper drying was defined as a ratio of energy used for moisture evaporation to total energy consumption, and expressed in combination of measurable temperature variables. The efficiency was compared with real evaporative efficiency and tested in the simulated and experimental drying. An overall drying efficiency was derived, and analyzed for various control variables consisting of drying temperature, air recycle ratio and air flow rate. Optimal operation conditions of drying was then searched by Box's complex method by using it as an objective function. Carotenoids retention was simulated and put as a constraint of product quality in the optimization. The optimization results gave that two staged drying operation could improve the ding efficiency compared with single staged drying. As a technique for further energy saving automatic termination of drying appeared feasible by monitoring an exit air temperature from dryer.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.116-122
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• 2004

Growth of Lactobacillus acidophilus in flour was investigated for production of noodle and bread. L. acidophilus grew when fermented in flour, and growth continued upon fermentation with salt for 72 hr. pH of L. acidophilus-fermented flour with salt decreased up to 72 hr, reaching 3.06. Fermented flour with salt showed no decomposition as compared to that without salt. In flour fermented by L. acidophilus, amounts of lactic and acetic acids produced increased with incubation time, and reached, after 72 hr incubation, 6,821 and 0.191 mg/g, respectively, resulting in significantly higher production of lactic acid. Viscosity of fermented flour with salt increased, whereas that without salt decreased with incubation time. Results reveal L. acidophilus-fermented flour with salt could be applied as effective agent in noodle and bread productions.

• Korean Journal of Food Science and Technology
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• v.20 no.5
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• pp.683-690
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• 1988

This study was conducted to determine the organoleptic and physical properties and carotenoid of commercial canned, frozen and freshly-made carrot juice. Samples were evaluated by sensory panel and measured for viscosity and acidity. For carotene analysis, HPLC of alpha- and beta-carotene, and spectrophotometry of total carotenoid content were used. Sensory evaluation indicated that the canned sample was less acceptable, especially for flavor and texture, than other juices, while forzen juice was considered as acceptable as freshly-made carrot juice. The canned product showed about 10 times higher viscosity and lower acidity than others. Between two kinds of frozen samples, one sample was the same as freshly-made sample for all parameters while the other showed less alpha-carotene content which was 2 times higher than that of canned one. Canned sample contained 70-77% of freshly-made or frozen samples in total carotenoid and beta-carotene content and 24% of freshly-made one in alpha-carotene. These results suggest that freezing process is a good preservation method for carrot juice with respect to sensory evaluation, physical property and carotenoid content.

• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.36-44
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• 2000

Survival of pathogenic bacteris(S. aureus, L. monocytogenes, E. coli and S. typhimurium) in tryptic soy broth containing green tea water extract(GTW), green tea ethanol extract(GTE), potassium sorbate (PS) and sodium benzoate(SB) stored at various pH was evaluated. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts and preservatives adjusted to pH 5.5, 6.0, 6.5 and 7.0 was inoculated approximately 105 CFU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 24∼48 hours. Survival of bacteria was determined by viable cell counts of bacterial culture at each pH. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of green tea extracts and preservatives against pathogenic bacteria were derived from survival curves of each bacteria. Antibacterial activities of green tea extracts increased with increasing pH but those of preservatives decreased with increrasing pH. S. aureus was the most sensitive strain to GTW and GTE but the most resistant to PS and SB. The MICs of green tea extracts to S. aureus were 0.52∼0.98% at pH 5.5∼6.0 and non inhibitory at pH 7.0. S. typhimurium was the most resistant to green tea extracts while the most sensitive to SB. The MICs of green tea extracts to S. typhimurium were 0.46∼1.62% at pH 5.5∼6.0 and 2% of PS was bactericidal at pH 5.5. 1.0∼2.0% of GTE were bactericidal to all strains tested except L. m9oncytogenes at pH 7.0. GTE was most efficient at inactivating pathogenic bacteria, generally followed by GTW, PS and SB.

• Food Science of Animal Resources
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• v.21 no.4
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• pp.358-366
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• 2001

To investigate the compositions of Holstein colostrums, samples were collected at 12 hour-interval after 12hrs postpartum. Milk protein, milk fat, SNF and total solid content of the colostum rapidly decreased from 12 hours to 48 hours after calving whereas lactose was the lowest at 12 hours after calving. Ash content was not shown to changes during lactation periods. Immunoglobulin G(IgG) concentration was also significantly(p<0.05) high in both primiparous and multiparous colostrum collected at 12 and 24 hours after calving. IgG concentration of primiparous and multiparous colostrums at 12 hours after calving was 44mg/ml and 44.27mg/ml, respectively. There was no apparent difference in IgG level between primipara and multipara. Fatty acid composition of colostral lipid was not shown to changes during lactation period. However, lauric acid, myristic acid and total saturated, fatty acid were slightly decreased in multiparous colostral lipid. Capric acid, myristic acid and palmitoleic acid composition in primiparous colostral lipid were slightly higher than those of multiparous colostral lipid throughout all lactation periods.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.596-601
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• 1993

Changes of textural properties of garlic pickle was studied during aging at room temperature with or without skin or addition of $CaCl_{2}$. The alcohol insoluble solids(AIS) was gradually decreased by aging. The decreasing rate of AIS was less for those of unpeeled and $CaCl_{2}-added$ pickles. In pectic substances, HSP was a little decreased and HXSP was significantly increased and HWSP and total pectin was changed little. The $CaCl_{2}-added$ pickles showed higher HSP and lower HXSP than those of $CaCl_{2}-not$ added pickles. The hardness of unpeeled pickles was slightly higher than peeled pickles and of $CaCl_{2}-added$ pickles was higher than $CaCl_{2}-not$ added pickles and decreased generally during aging for all samples.