• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.110-115
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• 2011

Shelf-life of brined baechu cabbage was extended by pasteurization at $65^{\circ}C$ for 30 min. Starters (Leu. citreum and Lab. plantarum) were added to the pasteurized brined cabbage to supply beneficial lactic acid bacteria during kimchi fermentation. Control kimchis made with baechu cabbage without pasteurization and no addition of the starters to the pasteurized cabbage kimchi were also prepared. The fermentation characteristics and health functionalities of DPPH free radical scavenging activities and in vitro anticancer effects in AGS human gastric cancer cells were compared. The pasteurized brined cabbage could not be fermented well and the functionalities were also low; however, the addition of starter(s), especially mixed starters of Leu. citreum and Lab. plantarum to the pasteurized brined cabbage, significantly increased the counts of lactic acid bacteria, hardness (texture) and overall acceptability in sensory evaluation. The free radical scavenging activities and the anticancer effects were also increased. The fermentation patterns of starter added kimchi prepared with pasteurized brined cabbage were similar to those of naturally fermented kimchi. It seemed that growth of lactic acid bacteria during kimchi fermentation contributed to increased taste and health functionality of kimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.899-906
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• 1996

The physicochemical and microbiological studies were conducted to examine the effect of pineneedle(Pinu densinora Seib. et Zucc) sap on the Kimchi fermentation. Kimchi with the addition of various levels(0, 0.5, 1.0, or 1.5%) of pine needle sap was fermented either at $4^{\circ}C$ for 15 days after placing at room temperature for 24 hours(Group A) or at $15^{\circ}C$ for 15 days(Group B). pH reached the optimal value of Kimchi fermentation(pH 4.2) on day 3 and day 4~7 in 0% treatment and pine needle sap treatments, respectively, which indicated that shelf-life of Kimchi was extended by 1~4 days by the addition of pine needle sap. Total acidity was decreased by the addition of pine needle sap. More rapid decrease in pH and increase in total acidity were observed in Group B than in Group A. Reducing sugar content was reduced to approximately 80% by day 4~5 in all treatments. Total vitamin C content was reached peak on day 1 of fermentation and then decreased in all treatments. Reducing sugar and total vitamin C contents were slightly increased by the addition of pine needle sap due to the components present in pine needle sap. Total viable cell number rapidly increased to reach Peak on day 3 and then slowly decreased during the fermentation. However, total viable cell number as well as reducing sugar and total vitamin C contents did not differ between Group A and Group B. In Group A, Lactobacillus cell number in 0% treatment continued to increase to reach peak on day 9, while the numbers in pine needle sap treatments reached Peak on day 5~9 and then gradually decreased throughout the fermentation. Unlike in Group A, Lactobaillus cell numbers in pine needle sap treatments in Group B continued to increase to reach Peak on day 7. As pine needle sap levels increased, total viable cell number and Lactobacillus cell number decreased regardless of fermentation temperatures. The results of this study indicate that pine needle sap causes to delay the Kimchi fermentation by slowing down pH drop and inhibiting the Lactobacillus cell growth.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.632-637
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• 1996

Effects of refrigeration temperature and its fluctuation range on the growth of psychrotrophic microorganisms and the quality of refrigerated foods such as apple, fish and oyster were evaluated to find optimum storage conditions for a domestic refrigerator. Refrigeration temperature was $2^{\circ}C$ or $4^{\circ}C$, and fluctuation ranges were varied: ${\pm}0.3,\;{\pm}1.0,\;{\pm}1.2,\;or\;{\pm}4.0^{\circ}C$. Changes in hardness of apples stored at $2{\pm}0.3^{\circ}C$ were much slower than those of apples stored at $4{\pm}1.2^{\circ}C$. Freshness of fish and oyster also lasted much longer at low temperature such as $2{\pm}0.3^{\circ}C$. The growth of Listeria monocytogenes inoculated on sliced ham was inhibited for 1 month at $2{\pm}0.3^{\circ}C$, but the cells at $4{\pm}1.2^{\circ}C$ began to grows as time elapsed. Therefore, it was expected that shelf-life of certain food stored in a domestic refrigerator could be extended by lowering temperature to $2^{\circ}C$ and by reducing fluctuation range of refrigerator.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.752-760
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• 2015

Effects of maltogenic amylase on textural properties of dough and quality characteristics of white pan bread were investigated. White pan bread was prepared with four different levels of maltogenic amylase contents (M-1: 0.048 U/g, M-2: 0.060 U/g, M-3: 0.072 U/g, M-4: 0.084 U/g). The setback by amylograph for the control was $480.0{\pm}12.25$ Brabender Unit (B.U.) while M-4 showed the a setback of $215.0{\pm}5.00B.U.$ The absorption, mixing tolerance index, and stability by farinogram were not significantly different (P>0.05) for across all treatments. The area under the curve (135 min) by extensogram was higher than all samples. The texture profile analysis results showed that there was significant decreasing in hardness for the maltogenic amylase infused bread (P<0.05). M-3 and M-4 showed higher springiness and cohesiveness but lower hardness than control over 1 to 3 days, indicating possibly extended shelf-life. Imaging scan showed that air cell size less than $0.4mm^2$ for the control and M-4 were at rates of 94.90% and 95.70%, respectively. For sensory evaluation, M-3 and M-4 showed higher intensities than the control for taste, flavor, texture, mouthfeel, and moistness quality. These results imply that the quality of white pan bread could be improved by adding maltogenic amylase without the use of chemical additives.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1296-1303
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• 2014

This study was conducted to develop predictive models for the growth of Bacillus cereus on carrot treated with slightly acidic electrolyzed water (SAcEW) and ultrasonication (US) at different storage temperatures. In addition, the inactivation of B. cereus by US with SAcEW was investigated. US treatment with a frequency of 40 kHz and an acoustic energy density of 400 W/L at $40^{\circ}C$ for 3 min showed the maximum reduction of 2.87 log CFU/g B. cereus on carrot, while combined treatment of US (400 W/L, $40^{\circ}C$, 3 min) with SAcEW reached to 3.1 log CFU/g reduction. Growth data of B. cereus on carrot treated with SAcEW and US at different temperatures (4, 10, 15, 20, 25, 30, and $35^{\circ}C$) were collected and used to develop predictive models. The modified Gompertz model was found to be more suitable to describe the growth data. The specific growth rate (SGR) and lag time (LT) obtained from the modified Gompertz model were employed to establish the secondary models. The newly developed secondary models were validated using the root mean square error, bias factor, and accuracy factor. All results of these factors were in the acceptable range of values. After compared SGR and LT of B. cereus on carrot, the results showed that the growth of B. cereus on carrot treated with SAcEW and US was slower than that of single treatment. This result indicates that shelf life of carrot treated with SAcEW and US could be extended. The developed predictive models might also be used to assess the microbiological risk of B. cereus infection in carrot treated with SAcEW and US.

• Food Science and Preservation
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• v.18 no.4
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• pp.612-619
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• 2011

Cronobacter sakazakii has been isolated from a wide range of environmental sources and from several foods of animal and plant origin. The objective of this study was to determine the resistance of C. sakazakii (ATCC 12868, ATCC 29004, and ATCC 29544) in cold, cold-freeze thaw, cold-acid, and cold starvation-freeze thaw stress. The number of C. sakazakii decreased to 1 log CFU/mL at $5^{\circ}C$ (cold storage) for 10 days. When C. sakazakii was cultivated at a low temperature ($13^{\circ}C$), the population of C sakazakii ATCC 12868 and 29004 increased to $10^9$ CFU/mL, and the population of C. sakazakii ATCC 29544 increased to $10^8$ CFU/mL. For C. sakazakii ATCC 12868 and 29004, the cold-adapted cells ($5^{\circ}C$ 24 hr) decreased by 4 log CFU/mL, and the low-temperature-cultivated cells ($13^{\circ}C$) decreased by 0.5 log CFU/mL. In this study, low-temperature cultivation enhanced the freeze-thaw cross-resistance due to the metabolic changes in the cells. Cold stress ($5^{\circ}C$ 48 hr, $13^{\circ}C$ cultivation) enhanced the cold-acid cross-resistance. The cold-starved cells in the sterilized 0.1% peptone water enhanced the freeze-thaw cross-resistance with significant differences (p<0.05). Therefore, the increased tolerance of the cold-adapted or low-temperature-cultivated C. sakazakii cells to freeze-thaw, acid, or starvation suggests that such environments should be considered when processing minimally processed foods or foods with extended shelf life.