• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.655-661
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• 1989

Optimal drying conditions consisting of air temperature and relative humidity were searched by the simulation-optimization technique for minimizing quality changes in red pepper drying. Optimized drying conditions were analysed in the viewpoint of quality change kinetics and effects of control variables on the state variables. Optimal drying conditions were nearly same in both cases for carotenoid maximization and browning minimization. In two staged optimized drying, relative humidity took a lower search limit of about 10%, and air temperature in the first stage was near the lower limit of $50^{\circ}C$ and in second stage increased to a higher temperature varying with total drying time and stage changing time. Response surface analysis of time invariable drying confirmed the location of the optimal point lying on the vertex of lower limit humidity and a lowest drying temperature which ensures to attain target moisture of 0.2g water/g dry solid. Two stage drying can attain the higher objective function of quality by 3-5% than time invariable drying for shorter total drying times.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.250-253
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• 1975

The acid milk containing grape juice was prepared from natural grape juice, acid milk and sugar as raw materials, and the stability of the drink was studied. The following results were obtained. 1. The milk mixed with natural grape juice formed coagulated precipitate by coupling of the colloidal materials in the juice with the milk protein and the formation of precipitate was accelerated by pasteurization. 2. The pectin in natural grape juice was affected on the stability of the product, and the stability increased with decrease in the content of pectin. When the content of pectin in natural grape juice was lower than 2.5mg%, the precipitate was not formed in the drink containing 10 to 20% of the juice. 3. The acid milk drink containing the natural grape juice treated with pectinase, not formed precipitate by pasteurization at $85^{\circ}C$, for 20 minutes and can be preserved for long term.

• KSBB Journal
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• v.21 no.2
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• pp.129-132
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• 2006

The importance of natural preservative has increased in recent years. The natural preservatives have been used in the field of foods, cosmetics and pharmacology. In the present work Artemisia sp., well recognized for their effect of antimicrobial activity, were extracted by methanol and water sequentially for selecting only water-soluble compounds that can be used as additives in food and cosmetics. Antimicrobial activities of water extracts from stem and leaf of Artemisia princeps var. orientalis were investigated by the disc diffusion method. Two gram positive bacteria(Staphylococcus aureus and Bacillus subtilis) and three gram negative bacteria(Escherichia coil, Agrobacterium tumefaciens and Pseudomonas putida) were used for antimicrobial activity studies. The water-soluble compounds from methanol extract showed higher antimicrobial activity than only water extract to these bacteria. Comparative evaluation of water-soluble metabolite profiles with caffeic acid that is known as an antimicrobial compound from Artemisia sp. was performed by high performance liquid chromatography with photo-diode array detection.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.4
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• pp.509-516
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• 2009

The CJ6 bacterial strain, which possesses strong antifungal activity, was isolated from meju and identified as Bacillus polyfermenticus based on Gram staining, biochemical properties, and 16S rRNA gene sequencing. B. polyfermenticus CJ6 showed antimicrobial activity against the various pathogenic molds, yeasts, and bacteria. Antifungal activity from B. polyfermenticus CJ6 was reduced after 24 hr at $70^{\circ}C$ but antifungal activity was not completely destroyed. The antifungal activity was stable in the pH range of $3.0{\sim}9.0$, and inactivated by proteinase K, protease, and ${\alpha}$-chymotrypsin, which indicate its proteinaceous nature. The apparent molecular masses of the partially purified antifungal compound, as indicated by using the direct detection method in Tricine-SDS-PAGE, was approximately 1.4 kDa.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1321-1326
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• 1998

Extraction and storage conditions of oleoresin were studied from root portion of peeled garlic, an waste of garlic industry. Extraction with ethanol and methanol showed an high solid yields of $27{\sim}37%$ at the temperature range of $30{\sim}50^{\circ}C$. Two hours of extraction were found to be economic because of no significant increase in furthur extraction. Storage of the oleoresin under anaerobic condition such as vaccum or nitrogen resulted in a less changes in pH, total acidity, color and thiosulfinate content, than those changes under aerobic condition. Most of the thiosulfinate was decreased for all conditions after 14 days of storage at $25^{\circ}C$. Glucose and sucrose were increased and most of organic acids were decreased during storage under nitrogen condition. Addition of ascorbic acid and cysteine into oleoresin retained the garlic flavor, effectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.469-474
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• 2002

This study was conducted to investigate the effects of gamma irradiation on the shelf-life extension of semi-dried squid (Todarodes pacificus). Semi-dried squid was stored at 10$^{\circ}C$ after gamma irradiation with doses of 0, 3, 5 and 7 kGy. In microbiological aspects, non-irradiated semi-dried squid was rapidly deteriorated during storage, and molds and yeasts were detected in a selective medium. The total viable cells were reduced with the increase of irradiation dose, and a dose level of 7 kGy was considered optimum and effective dose for the preservation of semi-dried squid. Increase in the content of volatile basic nitrogen was reduced by irradiation treatment depending upon doses. Thiobarbituric acid values were not significantly different in all samples regardless of irradiation. Sensory qualities of irradiated semi-dried squid were acceptable.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.408-414
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• 2017

Effects of pulsed electric field (PEF) processing on growth inhibition of indigenous aerobic microorganisms and the quality of mandarin and carrot juices were investigated. Mandarin juice was PEF-treated at 15-23 kV/cm for $23-241{\mu}s$, whereas carrot juice was treated at 13-14 kV/cm for 127-198 s. At $25^{\circ}C$ (inlet temperature), PEF treatments at 23 kV/cm for $104{\mu}s$ and 14 kV/cm for $198{\mu}s$ reduced the numbers of total mesophilic aerobes by $6.3{\pm}0.8$ and $5.5{\pm}0.9{\log}\;CFU/mL$ in mandarin juice and carrot juice, respectively. Elevation of inlet temperature to $40^{\circ}C$ increased the reduction rates in both juices. In general, the treatments resulting in the highest microbial inhibition at 25 and $40^{\circ}C$ did not alter the physicochemical and nutritional properties of both juices (p>0.05). PEF is a feasible technology to pasteurize mandarin and carrot juices commercially, with minimal quality deterioration.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.190-196
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• 1996

Kimchi vacuum packaged in PET/AI/PE pouch was stored at $0^{\circ}C\;and\;10^{\circ}C$ to evaluate the effect of vacuumizing conditions on quality changes. The quality of kimchi during storage was investigated in terms of pH, titratable acidity, color, viable counts of lactic acid bacteria including Leuconostoc and Lactobacilli and sensory properties. Titratable acidity and pH were not significantly different for the vacuum degrees. Color index (L b/a) values of crushed kimchi juice decreased exponentially and remained constant during storage, but the resulting color change was not affected by the vacuum degrees. Viable counts of lactic acid bacteria and sensory scores exhibited no significant difference among the kimchi of different vacuum degrees. Consequently, the vacuum degree in packaging of kimchi seemed to influence little on quality of kimchi. For enhancing the commercial value of vacuum packaged kimchi products, it would be appropriate to produce a slight vacuum, eliminating the head space, within packages.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.560-566
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• 2001

This study was conducted to investigate the effects of solvent extracts from medicinal plants on the fermentation of kimchi. Five microorganisms related to kimchi fermentation were selected and the antimicrobial activities of solvent fractions from medicinal plants were investigated. The chloroform fraction from the methanol extract of dandelion (Taraxacum platycarpum D.) exhibited inhibitory activity against five strains such as Lactobacilli plantarum, Lactobacilli brevis, Leuconostoc mesenteroides, Enterococcus faecalis and Saccharomyces cerevisiae. The chloroform fraction from the methanol extract of Dandelion inhibited the growth of E. faecalis and Leu. mesenteroides at the concentration of 80 mg/mL. Scanning electron micrographs of Leu. mesenteroides and E. faecalis treated with chloroform fraction 80 mg/mL exhibited morphological changes, including irregularly contracted cell surface.

• Korean Journal of Food Science and Technology
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• v.12 no.2
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• pp.82-87
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• 1980

The red color bleaching phenomena of red pepper powder by the exposure to sun light were studied on the various factors such as drying methods of pepper and the storage conditions of pepper powder, relative humidities, particle sizes, and the amounts and qualities of light. The surface color of red pepper was rapidly bleached by the successive daily exposures until the color retention value (capsanthin remained/original capsanthin content) reached to 0.5, while that of dark storge showed a negligible change. The color changes were related with the cumulative solar energy at various water activities $(a_w)$. As decreasing $a_w$ below 0.5, the bleaching reaction was highly accelerated, and thereafter was slowly progressed. Sun lights transmitted by red-, yellow- and blue-gelatin filters, respectivly, bleached in different degrees and at the shorter wavelength light, the more color bleaching occurred. From this fact a red colored package film could be effectivly used for the color preservation purpose in the red pepper storage.