• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.267-274
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• 2014

High pressure processing (HPP) is a non-thermal method used to prevent bacterial growth in the food industry. Currently, pasteurization is the most common method in use for most milk processing, but this has the disadvantage that it leads to changes in the milk's nutritional and chemical properties. Therefore, the effects of HPP treatment on the microbiological and chemical properties of milk were investigated in this study. With the treatment of HPP at 600 MPa and $15^{\circ}C$ for 3 min, the quantity of microorganisms and lactic acid bacteria were reduced to the level of 2-3 log CFU/ml, and coliforms were not detected during a storage period of 15 d at $4^{\circ}C$. An analysis of milk proteins, such as ${\alpha}$-casein, ${\beta}$-casein, ${\kappa}$-casein, ${\alpha}$-lactalbumin, ${\beta}$-lactoglobulin by on-chip electorophoresis revealed that the electrophoretic pattern of the proteins from HPP-treated milk was different from that of conventionally treated commercial milk. While the quantities of vitamins and minerals in HPP-treated milk were seen to be comparable to amounts found in raw milk, the enzyme activity of lipase, protease and alkaline phosphatase after HPP treatment was reduced. These results suggest that HPP treatment is a viable method for the control of undesirable microorganisms in milk, allowing for minimal nutritional and chemical changes in the milk during the process.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.100-106
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• 2001

The objective of this study was to improve the shelf-life of kimchi by freeze drying. Kimchi was freeze dried and stored at $0^{\circ}C$, $5^{\circ}C$ and $28^{\circ}C$ for 60 days. It was reconstituted with water at an interval of ten days and number of total lactic acid bacteria(LAB), sensory properties and shape/color were observed. The results were as follows: (1) Number of total LAB of sample stored at $0^{\circ}C$ or $5^{\circ}C$ for 60 days decreased gradually and the value of 10 day-sample and 30 day-sample was significantly different from the value of 0 day-sample and 20 day-sample, respectively (p<0.05). Number of total LAB of sample stored at $28^{\circ}C$ decreased more rapidly in comparison with that of sample stored at $0^{\circ}C\;or\;5^{\circ}C$. (2) Overall acceptability, taste, moistness and chewiness of freeze dried/reconstituted kimchi slightly decreased by freeze drying. However, acceptability of freeze dried/reconstituted kimchi was relatively good. (3) Overall acceptability of freeze dried/10 days-stored/reconstituted sample was slightly lower than that of reference sample (not-freeze dried sample). Overall acceptability of sample stored at $28^{\circ}C$ for 50 days decreased substantially in comparison with sample stored at $28^{\circ}C$ for 10 day. (4) In case of freeze dried/stored samples, sensory properties of sample stored at $5^{\circ}C$ for 60 days were not different from those of reference(sample stored at $0^{\circ}C$). Overall acceptability, taste, texture and crispness of sample stored at $28^{\circ}C$ started to decrease after 10 days. Odor and color of sample stored at $28^{\circ}C$ were changed after 50 days and 60 days, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.707-714
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• 2005

Ingredient ratio for making nabak kimchi and the manufacturing method were standardized from the available literatures. Fermentation properties and $CO_2$ production of the nabak kimchi were investigated during the fermentation at $5^{\circ}C,\;10^{\circ}C,\;and\;20^{\circ}C$. Standardized ingredients ratio of nabak kimchi that added 100 mL of water was as follows: 45.0 g baechu cabbage, 26.9 g radish, 1.9 g green onion, 1.0 g red pepper, 1.2 g crushed garlic, 0.9 g crushed ginger, 0.7 g red pepper powder. The standardized manufacturing method of nabak kimchi was as follows: washing ingredients, cutting radish and baechu cabbage $(2.5\times2.5\times0.5\;cm)$, salting for 20 min, washing and draining, pretreatment of ingredients, dissolving red pepper powder in water, blending, mixing, and adding the water to the mixed ingredients. Fermentations at $5^{\circ}C$ for 8 days, at $10^{\circ}C$ for 3 days, and at $20^{\circ}C$ for 1 day led to the acidity levels of $0.21\%,\;0.20\%,\;and\;0.31\%$, respectively. From the relationships between optimally ripened pH and acidity, nabak kimchi showed lower acidity of $0.20\~0.25\%$ with pH $4.2\~4.5.$ Like other kinds of kimchi, the Levels of Leuconostoc sp. were high specially at later stage of fermentation at low temperature $(5^{\circ}C)$. However, the levels of Lactobacillus sp. were low at $5^{\circ}C$. Nabak kimchi produced high levels of $CO_2$ in the initial fermentation period and followed by rapid decrease of $CO_2$ production with the fermentation. From the relationships between pH and $CO_2$ content, the highest $CO_2$ contents were found pH $4.0\~4.4$, 3.8 and 3.4 at $5^{\circ}C,\;10^{\circ}C$, and $20^{\circ}C$, respectively. This fact indicated that fermentation at $5^{\circ}C$ has the highest $CO_2$ content at optimally ripened pH of 4.3 and the fermentation at lower temperature such as $5^{\circ}C$ could extend the eatable time of nabak kimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.721-728
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• 2005

The physicochemical and microbial characteristics of pickled cucumber prepared with dry salting method, which has been used for industry, were investigated. Salting and storage conditions were HSHT $(30\%,\;25^{\circ}C)$, MSMT $(21\%,\;15^{\circ}C)$, MSLT $(21\%,\;0^{\circ}C)$, LSMT $(15\%,\;15^{\circ}C)$ and LSLT $(15\%,\;0^{\circ}C)$. Acidity was lower, and pH was higher in higher salt concentration as well as lower temperature groups. At the storage of 165 days, acidity and pH reached to $0.21\%$ and 4, respectively in MSLT and HSHT, of which conditions fermentation was retarded, compared to the other groups. During storage of pickled cucumber, greenness (-a) of Hunter color system showed the highest in MSLT ranged from -10.70 to -8.08, while in LSMT, the lowest to 1.17. Total microbial and lactic acid bacteria number in HTST and MSLT were the lowest than in other groups, while tile highest in LSMT. Yeast was not detected in HSHT and MSLT after 36 days of storage, while higher in LSMT Texture profile analysis exhibited that fracturability (2,318 g and 2,318 g) and hardness (849 g and 702 g) were highest in HSHT and MSLT, compared to the other groups. Scores of over-all preference for MSLT and LSLT were higher with 8.8 and 7.6, respectively, compared to the other products (p<0.05). Based on these results, lower saltiness and lower storage temperature condition was better for pickled cucumber preparation in industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.435-443
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• 2011

In this study, we evaluated the effects of harvey powder on the fernentation of Yulmoo Kimchi, by measuring sensory, physicochemical, and microbiological properties during fermentation up to 31 days. The Yulmoo Kimchi, with various levels [0, 0.1, 0.2, 0.3, 0.4% (w/w)] of harvey powder, was fermented at $10^{\circ}C$. The product containing the control evidenced the highest scores for appearance and smell. Taste, carbonated taste, texture and overall acceptability were highest in the 0.1% harvey powder and control. During fermentation, titratable acidity increased while pH gradually decreased. Reducing sugar showed no difference at initial fermentation and then steadily decreased. Total vitamin C was gradually decreased during fermentation and reduced sharply after 10 days, and then almost maintained. Total polyphenol content was the highest in the 0.3% harvey powder on day 0 and maintained in all samples thereafter. Antioxidant effect of the Yulmoo Kimchi with 0.1% harvey powder was shown to be the highest. Also, the time required to achieve maximum levels of lactic acid bacteria, as determined by log numbers of cells and total viable cells, were more delayed in the experimental groups with added harvey powder than in the controls. Our results indicated that the Yulmoo Kimchii with below 0.1% added harvey powder was acceptable.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1449-1455
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• 2006

Raw oysters were treated at $10^{\circ}C$ and $22^{\circ}C/350$ Mpa/15 min, and microbial counts and quality were measured during storage of 14 days at $10^{\circ}C$. Total viable cell count (TVCC) in untreated oyster increased greatly during storage from starting inoculum of $1.6\times10^2\;CFU/mL$, and reached to $5.6\times10^2\;CFU/mL$ after 4 days of storage. TVCC of the pressure-treated was about $10^1\;CFU/mL$ right after high hydrostatic pressure treatment and increased slowly during storage, and about $10^3\;CFU/mL$ even after 7 days of storage. Lactic acid bacteria count (LABC) in the untreated was increased greatly during storage from starting inoculum of $3.3\times10^3\;CFU/mL$ at 3 days of storage and $7.2\times10^4\;CFU/mL$ after 4 days of storage. LABC in the pressure-treated was detected only after 5 days of storage, and about $10^2\;CFU/mL$ after 8 days of storage. The pH of the untreated was 6.19 and decreased gradually during storage, and 5.83 after 4 days of storage. The pH of the pressure-treated showed little change during storage, and 6.07, 6.03 and 5.82 after storage of 4, 8 and 14 days, respectively. Volatile basic nitrogen (VBN) in the untreated was 16.8 mg%, and maintained almost constant until 1 day of storage, and then increased suddenly, and 30.1 mg% after 4 days of storage. VBN of the pressure-treated stayed unchanged during storage, and about 20 and 23 mg% even after 4 and 8 days of storage, respectively. Hunter $L^*,\;a^*\;and\;b^*$ values were increased until 2 days of storage and then showed no change during storage. Demerit score was the lowest in the thawed raw oyster, and then in the increasing order of the pressure-treated (4 day and 8 day storage) and the untreated (4 day storage).

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.267-276
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• 2005

This study was carried out to investigate the effects of Kimchi ingredients, garlic, ginger, green onion and fermented fish sauces, on the Kimchi characteristics during fermentation. The experiment design of this study was the central composite design and response surfaces methodology. Garlic (X$_1$) of 0∼2%, ginger (X$_2$) of 0∼1.4%, green onion (X$_3$) of 0∼4% and fermented fish sauces (shrimp, X$_4$ and anchovy, X$_{5}$) of 0∼2% per salted Chinese cabbage of 100 g put in independent variables, respectively. The result of response surface regression analysis, independent variables of various ingredients and dependent variables, correlation coefficient ($R^2$) showed very difference value according to added ingredients. In the Kimchi samples fixed independent variables of garlic (X$_1$)-ginger (X$_2$), generally, it showed high correlation value more than samples fixed other independent variables of garlic (X$_1$)-green onion (X$_3$) and ginger (X$_2$)-green onion (X$_3$) over the fermentation period. And the correlation coefficient ($R^2$) of fermented fish sauces (shrimp of X$_4$, anchovy of X$_{5}$) showed value over 0.8 in the its characteristics of Kimchi samples except for textural properties of sensory evaluation. In the graph pattern of fermented fish sauces using response surfaces methodology, it showed a little increasing value of titratable acidity, lactic acid bacteria and 'a' of redness, 'b' of yellowish according to increasing addition fermented fish sauces. In the total acceptability of sensory evaluation, it showed high value according to increasing fermented fish sauce at the initial fermentation period of Kimchi. But it showed high value Kimchi sample added content of 1.0% fermented fish sauce in the middle (appropriate fermentation) and last (excessive) fermentation period.

• Food Science and Preservation
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• v.23 no.5
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• pp.718-726
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• 2016

Sweet pumpkin paste (SPP) was fermented by Leuconostoc mesenteroides SM at $25^{\circ}C$ for 3 days for enhancing its physicochemical properties. SPPs with 5%, 10%, and 15% solid contents (SC) were fortified with 20% sucrose and 0.5% yeast extract. The unfermented SPP with 15% SC indicated L, a, and b color values of 25.02, 4.66, and 13.35, respectively, and a consistency index of $48.6Pa{\cdot}s^n$. During the 3 days of fermentation, both the a and b color values decreased slightly, whereas the consistency index increased to $188.8Pa{\cdot}s^n$, giving the fermented product a pudding-like consistency. This fermented SPP (15% SC) showed the highest acid production and viable cell counts among samples, indicating pH 3.85, 1.30% acidity and $9.2{\times}10^8CFU/mL$ respectively. The added sucrose was completely utilized after 1 day of fermentation. After 3 days, the insoluble and soluble dextran contents were 8.9% and 4.5%, respectively. Furthermore, the contents of mannitol and fructose were 3.11% and 1.76%, respectively. Regarding the sensory evaluation, this fermented sample also indicated the highest color, taste and texture scores, and was the overall preferred sample. In conclusion, the fermented SPP with 15% SC was carotinoid-rich a wholesome pumpkin-based product that is rich in probiotics and lactic bacteria-produced mannitol and dextran, which gave the product an acceptable viscous pudding-like consistency and good organoleptic properties.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.233-238
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• 2004

Foxtail Millet Takju was treated with heat ($65^{\circ}C/30\;min$) (HT) or high hydrostatic pressure ($27^{\circ}C/400\;MPa/10\;min$) (PT), and changes in microbial count, enzyme activity, and quality were determined during 30-day storage at 10 and $25^{\circ}C$. Total viable cellcount remained constant, while lactic acid bacteria and yeast were not detected in HT and PT Takjus. Relative activities of ${\alpha}-amylase$ in PT Takju significantly increased by 169.7% at 3 days storage, then decreased to 137.7 and 68.7% at 10 and $25^{\circ}C$, respectively, at 30 days. Relative activities of glucoamylase in HT Takju showed reversible change, and were 36.5 and 54.3% at $10\;and\;25^{\circ}C$, respectively, at 30 days storage. Activities in PT Takju increased with storage period, 158.2% at 30 days storage at $10^{\circ}C$. Titratable acidity in untreated Takju increased, while those in HT and PT Takjus remained almost constant during 30 days storage. Reducing sugar content in untreated Takju showed no change, while that in HT Takju increased gradually, reaching 2.9% at 30 days, whereas that in PT increased sharply after 3 days, reaching 4.8% at 30 days. Sensory evaluation showed sourness and bitterness were low, and sweetness and overall acceptance were high in PT Takju after 30 days storage at $10^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.217-223
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• 1979

The present study was to investigate the effect of sugars on the psychrophillic spoilage in ground meat. The obtained results were summarized as follows: 1. The minimum pH values for the ground beef containing 2, 5 and 10 % glucose were 5.25, 5.15 and 4.5, respectively. For the ground pork, the respective values were 5.1, 4.45 and 4.1. 2. Total aerobes, coliform, lactic acid bacteria and lactobacillus counts per gram for the control and 2% glucose-contained ground beef after 9 days for storage at $5^{\circ}C$ were $8.3{\times}10^9vs\;6.0{\times}10^7,\;3.5{\times}10^5vs\;2.4{\times}10^3,\;5.8{\times}10^7vs\;4.7{\times}10^6$ and $3.6{\times}10^5vs\;4.2{\times}10^6$ respectively. For the ground pork, the respective values were $1.2{\times}10^{10}vs\;7.8{\times}10^8,\;3.4{\times}10^5vs\;3.1{\times}10^4,\;5.5{\times}10^7vs\;4.5{\times}10^6$ and $3.3{\times}10^5vs\;3.7{\times}10^5$. The glucose-added ground meat showed higher counts than those of the controls only in the case of lactobacillus without any apparent adverse effects. 3. The length of storage time until the depletion of added glucose was 12, 16 and 28 days for the 2, 5 and 10 % glucose contained ground beef and 9, 16 and 30 days for the ground pork, respectively. pH did not start to increase until the added glucose was depleted completely. 4. The addition of glucose extended significantly the average shelf-life of ground beef at refrigeration condition $(5^{\circ}C)$. The extended shelf-life over the control was 7, 9 and 12days for the 2, 5 and 10 % glucose contained ground beef and 8, 10 and 12 days for the respective ground porks. 5. Although the addition of disaccharides (maltose, lactose, saccharose) lowered the pH of ground meat, the extension of shelf-life as seen in glucose treatment was not affected. In fact, the higher the concentration of added disaccharides was, the greater the degree of putrefaction occurred.