• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.292-297
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• 1996

In this study, biochemical changes of muscle protein in squid Sikhae prepared at various temperatures and moisture content were investigated. The pH values in squid Sikhae decreased rapidly with increase in titratable acidity during fermentation at high temperature and moisture content. Growth rate of lactic acid bacteria increased rapidly during fermentation at high temperature and moisture content. Changes in muscle protein subunit were analyzed by SDS-PAGE; myosin heavy chain component disappeared completely during preparation of squid Sikhae and actin component decreased slowly during fermentation. Therefore, it was suggested that myosin heavy chain component in squid muscle protein was autolyzed at the incipient for-mentation time and actin component was degraded by acidic protease in muscle and protease produced from microorganisms during fermentation.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1552-1558
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• 2021

The diverse microbial communities in kimchi are dependent on fermentation period and temperature. Here, we investigated the effect of enterotoxigenic Escherichia coli (ETEC) during the fermentation of kimchi at two temperatures using high-throughput sequencing. There were no differences in pH between the control group, samples not inoculated with ETEC, and the ETEC group, samples inoculated with ETEC MFDS 1009477. The pH of the two groups, which were fermented at 10 and 25℃, decreased rapidly at the beginning of fermentation and then reached pH 3.96 and pH 3.62. In both groups, the genera Lactobacillus, Leuconostoc, and Weissella were predominant. Our result suggests that microbial communities during kimchi fermentation may be affected by the fermentation parameters, such as temperature and period, and not enterotoxigenic E. coli (ETEC).

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.137-145
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• 1996

Chemical changes, lactic acid bacteria and yeast counts in kimchi prepared by a commercial manufacturer in large scale were monitored at different fermentation temperature. The optimum pH of kimchi, around pH 4.2, reached within 2 days at $25^{\circ}C$, 3 days at $15^{\circ}C$ and 23 days at $5^{\circ}C$ fermentation, respectively. The optimum acidity calculated as lactic acid was not exactly coincident with pH. The total viable count reached at maximum within 2 days at $25^{\circ}C$, 6 days at $15^{\circ}C$ and 12 days at $5^{\circ}C$ fermentation, respectively. The identified strains of Lactobacilli during kimchi fermentation were L. brevis, L. plantarum and L. acidophilus with 3 unidentified strains. L. brevis, L. plantarum appeared from the first stage of fermentation to the terminal at $15^{\circ}C$ and $25^{\circ}C$ with keeping a constant level of viable number. In case of Leuconostoc species, L. mesenteroides subsp. mesenteroides was identified. This strain increased in viable number at the beginning of fermentation and dropped sharply at all fermentation temperatures. Pediococcus species including P. pentosaceus and one unidentified strain increased at the first stage of fermentation and decreased after on. Streptococcus faecium subsp. casseliflavus which appeared at the middle stage and Aerococcus viridans which was sole strain were also confirmed during kimchi fermentation. Cryptococcus laurenti was identified at all fermentation temperature and disappeared at the first stage of fermentation. It was reappeared 10 days only after fermentation at $25^{\circ}C$.

• Food Science and Preservation
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• v.17 no.5
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• pp.608-615
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• 2010

We investigated the effect of grape-must temperature ($50^{\circ}C$, $60^{\circ}C$, and $70^{\circ}C$) on wine quality. We used Muscat Bailey A (MBA) grapes; these are often used in wine making in Korea. The numbers of viable bacteria, yeasts and molds in grape-must decreased with an increase in temperature. Polyphenol oxidase activities in grape-must were reduced at high temperatures. Redness; and, total anthocyanin, polyphenol, and tannin contents of MBA grape wine were higher after heating at $70^{\circ}C$ than after use of lower temperatures. Antioxidant activity was also enhanced after exposure to high temperatures, which may be attributable to the presence of increased levels of polyphenolic compounds in the grape-must. Thus, the heat treatment to prepare grape-must before wine fermentation greatly affects wine quality.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.414-418
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• 2006

The physicochemical characteristics and sensory properties of Jinyangju, a Korean traditional rice wine brewed using unique glutinous rice, were investigated over the following range of fermentation temperatures: 10, 15, 20 and $25^{\circ}C$. The pH value, total acidity, total sugar content, alcohol content and color value of the Jinyangju were determined after the 2-week fermentation, followed by sensory evaluation of the final product. After fermentation for 2 weeks at temperatures of 10, 15, 20 and $25^{\circ}C$, the final pH values were 3.70, 3.73, 3.40 and 3.26, the final total acidities were 1.04, 1.01, 1.39 and 1.72%, the final total sugar contents were 6.43, 6.22, 5.91 and 5.53% and the final alcohol contents were 14.20, 14.17, 14.83 and 15.40%, respectively. The color value of the Jinyangju was not different among the samples. In conclusion, the Jinyangju fermented at $15^{\circ}C$ showed the highest values in such sensory properties as color, flavor and odor, and was judged in the sensory evaluation to be the overall favorite.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.2019-2027
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• 2017

Recently, cabbage kimchi has occasionally been associated with the foodborne diseases of enteric viruses such as human norovirus (HuNoV). This study aimed to evaluate the correlation between microbial/physicochemical properties and persistence of HuNoV in experimentally contaminated cabbage kimchi fermented and stored at $4^{\circ}C$ or $10^{\circ}C$ for 28 days. Changes in organic acid content, lactic acid bacteria (LAB), acidity, pH, and salinity were analyzed. The recovery of structurally intact HuNoV was examined for up to 28 days post-inoculation, using a NoV GII.4 monoclonal antibody-conjugated immuno-magnetic separation method combined with quantitative real-time reverse transcription polymerase chain reaction. On day 0, LAB loads were $4.70log_{10}$ colony forming units/g and HuNoV GII.4 titers were $2.57log_{10}\;genomic\;copies/{\mu}l$, at both temperatures. After 28 days, intact HuNoV titers decreased to 1.58 ($4^{\circ}C$) and $1.04(10^{\circ}C)log_{10}\;genomic\;copies/{\mu}l$, whereas the LAB density increased. This correlated with a gradual increase in lactic acid and acetic acid at both temperatures. Our findings support a statistical correlation between changes in physicochemical properties and the recovery of structurally intact HuNoV GII.4. Moreover, we determined that the production of organic acid and low pH could affect HuNoV GII.4 titers in cabbage kimchi during fermentation. However, HuNoV GII.4 was not completely eliminated by microbial/physicochemical factors during fermentation, although HuNoV GII.4 was reduced. Based on this, we speculate that the persistence of HuNoV GII.4 may be affected by the continually changing conditions during kimchi fermentation.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.305-311
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• 2017

This study aimed to evaluate the fermentation characteristics of mixed Makgeolli with barley and wheats under, fermentation at different temperatures (20, 25, and $30^{\circ}C$) and time (3, 6, and 9 days). The pH and sugar of mixed Makgeolli were 3.68~4.26 and $12.30{\sim}17.31^{\circ}Brix$, respectively. The total acidity showed proportionate increase with fermentation temperature and time; whereas, reducing sugar contents decreased with increasing fermentation temperature and time. The alcohol contents of mixed Makgeolli varied significantly by fermentation temperature and time (p<0.05). In terms of color values, the L value decreased with increasing fermentation temperatures, and a value increased significantly with increasing fermentation time. The number of microorganisms (yeast, total bacteria and lactic acid bacteria) in mixed Makgeolli decreased progressively with increasing fermentation temperature and time. Among the organic acids (citric, lactic, malic, and pyruvic acids) in mixed Makgeolli, citric and lactic acid was present at the highest concentrations. From these results, the optimum fermentation conditions of mixed Makgeolli with barley and wheat were $20{\sim}25^{\circ}C$ for 6 days.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.607-614
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• 2005

To determine the optimum fermentation condition, the 50:50 feed mixture of both crushed corn and wet brewer’s grain were anaerobically fermented at various conditions. Three supplementation levels(0, 2%, and 5%) of molasses, five supplementation levels(0, 0.1%, 0.5%, 1.0%, and 2.0%) of yeast and five different incubation temperatures(4$^{\circ}C$, 10$^{\circ}C$, 30$^{\circ}C$, 40$^{\circ}C$ and 50$^{\circ}C$) were tested to determine the optimum fermentation conditions. During fermentation, alcohol concentration, live yeast cell number (LYCN) and pH values of the mixture were analyzed. Alcohol concentrations of the fermented feed mixtures were proportionally increased with increasing level of molasses supplementation. After 24hr fermentation, alcohol concentrations at 0.1%, 0.5%, 1.0% and 2.0% of yeast supplementation was 1.9%, 2.4%, 3.1% and 3.1%, respectively. These results indicate a proportional increase of alcohol concentration with the increasing supplementation of yeast (P<0.05) up to 1%, thereafter showing plateau at 2% supplementation. LYCN was relatively high with more than 0.5% yeast supplementation, whereas the value was significantly low(P<0.05) at 0.1% yeast supplementation. Alcohol production was significantly higher at 30$^{\circ}C$ and 40$^{\circ}C$ than other incubation temperatures (P<0.05), with the highest concentration at 30$^{\circ}C$. pH was rapidly decreased until 24 hours of incubation with steeper decrease at lower temperatures(P<0.05). Based on there results, optimum fermentation conditions for the alcoholic-fermented feed production could be achieved with 5% supplementation of molasses, 1% supplementation of yeast, and 24hr long incubation at 30$^{\circ}C$.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.3
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• pp.369-378
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• 2011

The effect of a homolactic inoculant containing a blend of Lactobacillus plantarum, Pediococcus acidilactici and Enterococcus faecium or, the anionic surfactant, sodium dodecyl sulphate (SDS), alone or in combination on fermentation characteristics, aerobic stability and in situ DM, OM and NDF degradability of barley silage was investigated. Barley (Hordeum vulgare, L.) was harvested (45% DM), chopped and treated with water at 24 ml/kg forage (Control), inoculant at $1.09{\times}10^5$ cfu/g forage (I), SDS at 0.125% (wt/wt) of forage (S) or with the inoculant ($1.09{\times}10^5$ cfu/g) plus SDS (0.125% wt/wt; I+S). The treated forages were ensiled in triplicate mini silos and opened for chemical and microbiological analyses on d 1, 2, 3, 7, 14, 42 and 77. Silage samples from d 77 were opened and aerobically exposed for 7 d. The in situ rumen degradability characteristics of silage DM, OM and NDF were also determined. The terminal concentration of NDF in S and I+S was lower (p<0.001) than in other treatments. Lactate concentration was higher (p<0.001) and the rate and extent of pH decline were greater (p<0.001) in I and I+S than S and Control silages. A homolactic pathway of fermentation in I and I+S was evidenced by reduced (p<0.001) water-soluble carbohydrates concentration, higher lactate (p<0.01), lower acetate (p<0.01) and lower pH values (p<0.001) than in S and Control silages. All silages remained stable over 7 d of exposure to air as indicated by lower temperatures and moulds, and by non-detectable yeast populations. The treated silages had lower DM and OM degradability than in the Control but NDF degradation characteristics of I+S were improved compared to other treatments. It is concluded that the inoculant alone improved the fermentation characteristics whereas the combination of the inoculant with SDS improved both fermentation and NDF degradability of barley silage.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.784-789
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• 1997

The difference of quality characteristics between whole Chinese cabbage kimchi (pogi kimchi) and sliced Chinese cabbage kimchi (mat kimchi) was examined during fermentation at $20^{\circ}C\;and\;5^{\circ}C$. Pogi kimchi showed a delayed fermentation about 2 days at $20^{\circ}C$ and 10 days at $5^{\circ}C$. L (lightness), a (redness) and b (yellowness) of pogi and mat kimchi gradually increased during fermentation. These values were revealed slightly higher for mat kimchi at $20^{\circ}C\;than\;at\;5^{\circ}C$. $CO_{2}$ concentration within package steeply increased for both types of kimchi in 3 days, but $O_{2}$ concentration was decreased until that time. The number of lactic acid bacteria of mat kimchi was generally higher than that of pogi kimchi at $20^{\circ}C$, but pogi kimchi showed higher lactic acid bacteria at $5^{\circ}C$. Smell, color and taste of kimchi fermented at $20^{\circ}C$ was better than those of kimchi fermented at $5^{\circ}C$, but there were no great differences between pogi kimchi and mat kimchi.