• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.469-476
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• 2000

Inhibitory action of major food components on antimicrobial active substance (linolenic acid) was tested against Listeria monocytogenes ATCC 19111 for 72 hr at $30^{\circ}C$. Linolenic acid (50, 1000 ppm) and n-hexane fraction of Mallotus japonicus Muell (50, 1000 ppm) were added to the broth culture medium containing casein(1%, 3%), soybean oil(1%, 3%) and soluble starch (1%, 3%), respectively. Linolenic acid 1000 ppm and n-hexane fraction 1000 ppm exhibited strongly antimicrobial actions on L. monocytogenes which were not detected viable cell after 24 hr. But casein (3%) and soybean oil (3%) strongly diminished the antimicrobial action of 1000 ppm of n-hexane fraction. Soluble starch (1%, 3%) did not affect the antimicrobial action of 1000 ppm of linolenic acid and n-hexane fraction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1050-1057
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• 1997

Microbial counts, enzyme activities and taste components of traditional kochujangs prepared with the powders from 4 different varieties of red pepper, were investigated during 90 days fermentation for the industrial production of traditional kochujang. The viable cell counts of anaerobic bacteria in kochujangs did not change remarkably during fermentation, however, aerobic bacterial counts showed a rapid increase up to 90 days of aging. The yeasts in all kochujang samples increased until 60 days of aging and than decreased. After 90 days of aging, the count of aerobic bacteria in Kumtop kochujang was higher than those of others. The activities of liquefying amylase decreased during the aging, but those of saccharogenic amylase increased at 60 days of aging. The activities of neutral protease were higher than those of acidic protease, and increased during the middle and last period of aging. The major free sugars of kochujang were maltose and glucose, and their contents were higher in Hongkwang kochujang. The major organic acids of kochujang were succinic, formic and citric acid, followed by lactic acid. Succinic acid content in kochujang decreased during fermentation, whereas formic and citirc acids were increased. The major free amino acids were serine, proline, glutamic acid, aspartic acid and alanine. Kumtop kochujang contained the highest amount of total free amino acids. Among the nucleotides and related components in kochujang, cytidine-5-monophosphate was the most abundant component at the begining of aging period, while hypoxanthine increased remarkably during fermentation. Hanwang kochujang was higher in the content of nucleotides than others. Capsaicin contents of kochujang decreased during aging and those of Jangter kochujang was higher than that of others. Sensory evaluation showed that Jangter kochujang was significantly better than Kumtop kochujang in overall acceptability, but there were no appreciable differences in color and flavor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.588-594
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• 1997

In this study, the shelf-life of Kochujang during storage was predicted through physicochemical and sensory analyses. Amino nitrogen, lightness, characteristics of surface color, pH and number of viable cell counts in Kochujang decreased during storage, while ammonia nitrogen, titratable acidity and viscosity increased. Among the physicochemical analyses, amino nitrogen content exhibited the highest correlation with sensory score. The marginal amounts of amino nitrogen was 170.6mg%. Degradation rate of amino nitrogen was a first order reaction. Q$_{10}$-value and the activation energy of Kochujang during storage were 1.80 and 8.6kca1/mol, respectively. The shelf-life Predicted of Kochujang at each storage temperature was calculated. The shelf-life predicted was 467 days at 1$0^{\circ}C$, 261 days at 2$0^{\circ}C$ and 133 days at 35$^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.912-918
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• 2006

This study examined the improvement of bread quality with Curcula longa and Glycyorrhiza uralensis extract (CGE). When counted, the viable cell number in bread with 5% of CGE dramatically was decreased by about 1 log cycle as compared to that of bread without CGE. With regard to oxidation, the content of malonaldehyde diminished in breads with increasing amounts of CGE. Breads with 1 and 5% of CGE were shown to have the highest antioxidative effect. The moisture contents of bread with CGE and bread without CGE were not much different during the early storage period. After six days of storage, however, the moisture contents of bread without CGE and bread with 0.5% of CGE decreased about 16%. On the other hand, the moisture contents of bread with 1% and 5% of CGE did not change dramatically. Their moisture content was decreased by only 4% during the same storage period. Although color, lightness and redness gradually diminished with increasing amounts of CGE in bread, conversely yellowness increased. In the sensory evaluation, bread with 0.5% and 1% of CGE scored the highest: 3.66 and 3.67 out of 5, respectively. Bread with 5% of CGE scored the lowest of the various bread tested. From these results, the addition of 1% CGE in bread had a good effect on improvement of preservation and development of quality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.2
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• pp.139-147
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• 1991

The preservative effect of cellophane film packing on the quality of semi-salted and dried mackerel was studied. The product(P) of semi-salted and dried mackerel was prepared from raw mackerel by filleting, cleaning, soaking in 15%9v/w) salt solution for 30min, draining, packing with cellophane film (PT# 300, thickness:$20{\mu}{\textrm}{m}$) and drying for 4 hrs at $40^{\circ}C$ in hot air dryer. The product (C) was also prepared without cellophane film packing after draining. The product (C) and (P) were stored at $5.0{\pm}0.5^{\circ}C$. After processing and during storage, moisture content of product (P) was higher than that of product (C), but contents of VBN(volatile basic nitrogen), amino nitrogen and TMA of product (P) on dry basis were lower than those of product (C). Viable cell count, TBA value, peroxide value and decreasing rate of polyenoic acid of product (P) were also lower than those of product (C). In sensory evaluation, the shelf life of product (C) was about 9 days and that of product (P) was about 14 days. From the results of chemical and sensory evaluation, it was concluded that cellophane film packing was a good condition for preserving the quality of semi-salted and dried mackerel.

• Food Engineering Progress
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• v.14 no.1
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• pp.14-20
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• 2010

The objective of the current study was to determine the cryoprotective effects of trehaolse on lactic acid bacteria in the frozen yoghurt during long-term frozen storage conditions. The frozen yoghurts were prepared using starter culture containing Lactobacillus bulgaricus and Streptococcus thermophilus, as well as trehalose and sorbitol as a cryoprotectant. The viable cell numbers of lactic acid bacteria in frozen yoghurt did not significantly decreased during six weeks frozen storage conditions. The MRS broth, which contains either trehalose or sorbitol, cultured with L. bulgaricus and/or S. thermophilus, and then the cultured medium was kept in the frozen condition for six weeks. The results indicated that lactic acid bacteria viability significantly increased with trehalose addition (2 and 5%) in the media compared to those of control and sorbitol supplement groups. The lactic acid bacteria viability in the yoghurts was examined on the effects of repeated freeze and thaw events. The freeze-thaw resistance of lactic acid bacteria significantly increased with trehalose supplement in the yoghurt. The major volatile aroma compounds (acetaldehyde, acetone, ethanol, diacetyl, and acetoin) in yoghurt were separated and indentified by headspace GC-FID analysis. Distinct flavor components and their ratios are known as important quality factors for yoghurt notes. Trehalose addition to the yoghurt was not influenced these factors during lactic acid fermentation. The results in this study demonstrated that trehalose potentially can be applicable as an effective cryoprotectant for lactic acid bacteria in the frozen yoghurt products.

• Food Science and Preservation
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• v.12 no.4
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• pp.395-401
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• 2005

This study was carried out to investigate the changes in the fermentation characteristics of Kimchi prepared with various salts (Korean solar salt, Chinese solar salt, washed and dehydrated salt, purified salt and a processed salt). Acidity appeared to increase most rapidly in Kimchi prepared with Korean solar salt and reached higher level. Total microbial count slowly increased at the beginning of fermentation and reached maximum on 6 days, then decreased slowly. The number of lactic acid bacteria was rapidly increased up to $4{\sim}6$ days, and thereafter decreased slowly. In conclusion, any significant differences in fermentation characteristics analyzed was not observed in Kimchi prepared with various salts except acidity.

• Food Science and Preservation
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• v.15 no.5
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• pp.774-781
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• 2008

was performed and Staphylococcus sciuri, Bacillus cereus, Escherichia coli, Proteus mirabilis, and Enterococcus faecalis were identified. No Salmonella strain, a typical contaminant of eggs, was found. The radiation sensitivities of isolated bacteria and Salmonella typhimurium, in an inoculated model system, were expressed in $D_{10}$ values. The ranges of $D_{10}$ values shown by S. typhimurium, S. sciuri, B. cereus, E. coli, P. mirabilis, and E. faecalis were 0.365-0.399 kGy, 0.418-0.471 kGy, 1.075-1.119 kGy, 0.280-0.304 kGy, 1.132-1.330 kGy, and 0.993-1.290 kGy, respectively. The growth of all six test bacteria in eggs (inoculated at $10^6-10^7\;CFU/g$) during 3 days of post-irradiation storage at ambient conditions ($25^{\circ}C$) was recorded. S. typhimurium was eliminated by irradiation at 3 kGy, and E. coli and S. sciuri were eliminated by irradiation at 5 kGy. The viable cell counts of B. cereus, P. mirabilis, and E. faecalis in eggs showed 4-6 log reductions after irradiation with 5 kGy.

• Food Science and Preservation
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• v.15 no.5
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• pp.648-655
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• 2008

A gamma irradiation process was applied to prolong the shelf-life of grapes and changes in microbiological, physicochemical, nutritional, and sensory characteristics were investigated during 6 weeks of post-irradiation storage at $4^{\circ}C$ and $25^{\circ}C$. Physiochemical characteristics of grapes such as total sugar content, pH, titratable acidity, and anthocyanine content, were stable after 1 kGy of irradiation, a dose recommended by CODEX for fruits and vegetables. The viable cell counts of contaminating microorganisms were reduced 1-2 logs by this radiation dose. After 6 weeks of storage at $4^{\circ}C$ the microbiological quality of irradiated grapes was stable, but all non-irradiated grapes had deteriorated. Whether or not grapes were irradiated, weight loss rapidly increased after 2 weeks of storage at $25^{\circ}C$, whereas weight loss was delayed by storage at $4^{\circ}C$. Immediately after gamma irradiation, the sensory evaluation results did not differ between samples, and the sensory quality of the irradiated grapes remained acceptable for over 6 weeks of storage at $4^{\circ}C$. The results suggest that 1 kGy of gamma irradiation does not detrimentally affect the nutritional or physical characteristics of grapes, especially when cold storage follows radiation treatment. In conclusion, a combination of gamma irradiation and cold storage prolonged the shelf-life of grapes by 6 weeks.

• Food Science and Preservation
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• v.18 no.3
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• pp.288-293
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• 2011

This study investigated the changes in the quality of fresh-cut lotus roots that were treated with hot water. Lotus roots were purchased from Daegu, Korea. They were washed, peeled, and cut into lcm-thick slices with a ceramic knife. The peeled and sliced lotus roots were dipped for 45 sec in water at 30, 55, and $80^{\circ}C$. After they were air-dried at room temperature, the slices were packed in polyethylene films and stored at $4^{\circ}C$ for 12 d. Then the changes in the weight loss, color, total viable cell, and sensory characteristics were measured. Generally, the weight loss of the lotus roots that were treated with hot water slightly increased. The application of the heat treatment delayed the browning of the lotus roots, especially the treatment with $55^{\circ}C$ hot water. The L and a values of the lotus roots that were treated with $80^{\circ}C$ hot water significantly increased during their storage, though. The heat treatment effectively inhibited the growth of microorganisms. The organoleptic quality of the lotus roots that were treated with $55^{\circ}C$ hot water was the best.