• Title/Summary/Keyword: Bacteria

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Microbiological Safety of Minimally Processed White Radish in Modified Atmosphere Packaging Combined with Irradiation Treatment (가스치환포장과 감마선조사 병용 처리한 최소가공 무의 미생물학적 안전성)

  • Kim, Jae-Kyung;Jo, Cheo-Run;Kim, Hyun-Ju;Lee, Ju-Woon;Hwang, Han-Joon;Byun, Myung-Woo
    • Korean Journal of Food Science and Technology
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    • v.37 no.1
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    • pp.11-14
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    • 2005
  • White radish was minimally processed, packed with air, $CO_{2}$ (100%), and $CO_{2}/N_{2}$ (25/75%), and irradiated at 0, 1, and 2 kGy, and its microbiological quality and pH were investigated during storage for 2 weeks at $4^{\circ}C$. Irradiation significantly reduced total aerobic, coli-form, and lactic acid bacteria counts. Modified atmosphere packaging (MAP) enhanced microorganism control during storage. Acidity decreased by MAP but was restored during storage, Irradiation did not affect sample pH. Results show irradiation at 2 kGy combined with MAP can enhance microbiological safety and quality of minimally processed radish.

Changes in Quality Attributes of Sigumjang with Fermentation (시금장 발효기간에 따른 품질 변화)

  • Choi, Ung-Kyu;Kwon, O-Jun;Son, Dong-Hwa;Cha, Won-Seop;Cho, Young-Je;Lee, Suk-Il;Yang, Sung-Ho;Chung, Yung-Gun
    • Korean Journal of Food Science and Technology
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    • v.33 no.1
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    • pp.107-112
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    • 2001
  • The various components of sigumjang were analyzed according to fermentation time. Aerobic bacteria were increased with fermentation time. Yeasts and molds were increased until 3 days after fermentation and then not changed. Six free sugars, 3 volatile organic acids and 6 non-volatile organic acids were detected. The content of free amino acids was $1,407.9{\sim}3,053.9\;mg%$. Glutamic acid was most abundant component among the amino acids, followed by phenylalanine, arginine and valine. The ratio of essential amino acid was $34.4{\sim}37.0\;mg%$. The content of mineral was $12,966.7{\sim}13,864.5\;mg%$. Potassium was the most abundant in quantity among the minerals in sigumjang except sodium which was added artificially. The principal fatty acids were linoleic acid, palmitic acid and oleic acid. The ratio of unsaturated fatty acids was $76.3{\pm}1.1%$. As a result of sensory evaluation, the highest score was obtained 3 to 5 days after fermentation.

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Bacterial Distribution of Kochujang (개량식 및 재래식 고추장의 세균 분포)

  • Lee, Jeong-Mi;Jang, Jae-Hee;Oh, Nam-Soon;Han, Min-Su
    • Korean Journal of Food Science and Technology
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    • v.28 no.2
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    • pp.260-266
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    • 1996
  • This study was carried out to investigate the bacterial microflora of commercial and traditional Kochujang. Computer aided idetification systems were used to identify the bacteria in Kochujang. Seven genera such as Bacillus, Corynebacterium, Enterococcus, pasteurella, Pseudomonas, Staphylococcus and Streptococcus in commercial process and 10 genera such as Bacillus, Corynebacterium, Enterococcus, Flavimonas, Flavobacterium, Gemella, Pasteurella, Pseudomonas, Staphylococcus and Streptococcus in traditional process were identified. Distribution of genus Bacillus was $56{\sim}70%$ during fermentation in the commercial process and $38{\sim}50%$ in the traditional process. B. lichenoformis strains identified in this study were classified into three types by their physiological characteristics.

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Effects of High Hydrostatic Pressure on the Shelf-life and Quality of Dongchimi (초고압처리 동치미의 저장 안정성 및 품질 특성)

  • Hong, Kwan-Pyo;Park, Ji-Yong
    • Korean Journal of Food Science and Technology
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    • v.30 no.3
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    • pp.602-607
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    • 1998
  • Changes in microbial count, enzyme, texture and color during storage of dongchimi (pickled radish roots) were investigated. Dongchimi was pressurized at 400 MPa for 5 min. Pressurized dongchimi stored at $4^{\circ}C\;(PS4)\;and\;37^{\circ}C\;(PS37)$ were compared with control $(stored\;at\;4^{\circ}C)$. PS4 and PS37 maintained their initial pH values during storage. Lactic acid bacteria, yeast and mold were not detected during storage in pressurized dongchimi. Pectinesterase, polygalacturonase activities and hardness of pressurized dongchimi decreased during storage. PS4 maintained its hardness longer than both control and PS37 during storage. The yellowness of PS37 was too high compared to control and PS4, indicating that storage of pressurized dongchimi at $37^{\circ}C$ was undesirable.

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Physicochemical and Sensory Characteristics of Kakdugi Added with Xanthan Gum during Fermentation (Xanthan Gum첨가 깍두기의 이화학적.관능적 특성)

  • 김혜영;김미리
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.2
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    • pp.196-203
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    • 2002
  • Effect of different levels (0 ,0.05, 0.15, 0.25%) of xanthan gum on kakdugi fermentation was investigated by analyzing physicochemical and sensory characteristics during fermentation at 2$0^{\circ}C$. During fermentation, pH was maintained higher, and total acidity and number of lactic acid bacteria, maintained lower in xanthan gum groups, especially in 0.05% addition group than control. Free sugar amount were higher in xanthan gun groups than control, and glucose and fructose which were the major free sugars, decreased rapidly during fermentation, whereas mannitol increased in all samples, especially in xanthan gum groups. Liquid content of kakdugi was smaller in 0.05% xanthan gum group than control. Viscosity of kakdugi liquid decreased rapidly whereas initial viscosity was maintained in xanthan gum groups. Hardness decreased during fermentation, but at the 7th day of fermentation was higher in 0.05% xanthan gum group than control. The result of sensory evaluation shows that there were no significant difference in sour odor, moldy, sour taste and savory taste among samples. Starch taste was higher in 0.15% or 0.25% xanthan gum, but there is no difference in 0.05% group, compared to control. Overall preference until the 5th day of fermentation, xanthan gum group was not significantly different from that of control but at the 7th day of fermentation, 0.05% addition group was significantly higher than control.

Antimicrobial Effect of Rubia akane Nakai Extract on Food-Borne Pathogens (식중독유발 세균의 증식에 미치는 천초근 추출물의 영향)

  • Bae, Ji-Hyun;Jang, Hye-Jung;Jung, Jung-Im
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.3
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    • pp.389-394
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    • 2005
  • This study was performed to investigate the antimicrobial activity of the Rubia akane Nakai extract against food-borne pathogens. First, the Rubia akane Nakai was extracted with methanol at room temperature and the fractionation of the methanol extract was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol. The antimicrobial activity of the Rubia akane Nakai extract was determined by using a paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extract of Rubia akane Nakai showed the highest antimicrobial activity against Bacillus cereus and Pseudomonas aeruginosa. Synergistic antimicrobial effect was observed when Rubia akane Nakai extract was mixed with Viscum album var. coloratum extract as compared to each extract alone. Finally, the growth inhibition curves were determined by using methanol extract of Rubia akane Nakai against Bacillus cereus and Pseudomonas aeruginosa. The methanol extract of Rubia akane Nakai had strong antimicrobial activity against Pseudomonas aeruginosa at the concentration of 4,000 ppm. At this concentration, the growth of Pseudomonas aeruginosa was retarded more than 72 hours and up to 48 hours for Bacillus cereus. From these results, it was concluded that the methanol extract of Rubia akane Nakai inhibited effectively Bacillus cereus and Pseudomonas aeruginosa.

Development of Jelly Fortified with Lactic Acid Fermented Prickly Pear Extract (백년초 젖산 발효액을 이용한 젤리의 제조)

  • Son, Min-Jung;Whang, Ki;Lee, Sam-Pin
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.3
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    • pp.408-413
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    • 2005
  • Rheological properties and sensory characteristics of prickly pear jelly made from κ-carrageenan and glucomannan were examined. Prickly pear extract (PPE) fermented by Lactobacillus casei LS (isolated from soy milk curd residue) exhibited pH 3.12, 1.15% acidity (lactic acid) and 2.7 × 10/sup 9/ CFU/mL lactic acid bacteria. In the effect of concentration of fermented PPE, the jelly containing 4% fermented PPE had higher springiness and slightly lower hardness than that without fermented PPE, and was superior to color and taste. The hardness and brittleness of jellies were enhanced by the addition of 0.25% citric acid. The addition of 0.25% ascorbic acid resulted in the production of soft jelly like pudding. In the effect of concentration of κ-carrageenan, the hardness and springiness of jellies were increased by adding 0.75% κ-carrageenan, but was decreased by adding at the 0.9% level. In the overall preference of jellies including sweet and sour taste, higher score was obtained by the fortification of 0.6% and 0.75% κ-carrageenan, 0.25% citric acid and 30% fructose syrup.

Effect of Water Extracts of Shellfish Shell on Fermentation and Calcium Content of Kimchi (김치의 숙성과 칼슘함량에 미치는 조개류 껍질 물추출물 첨가효과)

  • 김미정;김미향;김순동
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.2
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    • pp.161-166
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    • 2003
  • This study attempted to fortify Kimchi with water extracts of shells of shellfishes (corb shell, short neck clam, taste clam, ark shell, top shell, oyster) as natural resource of calcium. Kimchi added with the shell extracts in 5% were fermented at 1$0^{\circ}C$ with measurements in chemical, microbiological and sensory qualities. Calcium content of shellfish shells before water extraction was in the range of 25.57~38.78%. Kimchi added with the extracts showed higher pH, lower acidity, lower total aerobic bacterial count and higher lactic acid bacteria count compared to control Kimchi without any addition. After 7 day fermentation the Kimchi added with the extracts also showed higher ash and calcium contents compared to control products (3.3~5.0 vs. 2.8~3.0% and 300~376 vs. 70~95 mg%). Kimchi with oyster shell extract gave the most pronounced effect in ash and calcium contents. The addition of extract made Kimchi crisper and less sourer oganoleptically. In the overall acceptability, the Kimchi fortified with the shell extracts were better than control after 14 day fermentation.

Development of the Formula for Natural Bread-making Starter (천연제빵 발효 Starter의 개발)

  • 이종열;이시경;조남지;박원종
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.8
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    • pp.1245-1252
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    • 2003
  • A starter formulation was developed to substitute a baker's yeast with natural starter when manufacturing bread products. To develop an active starlet, starter was formulated varying with types of wheat flours, level of water contents and various nutrients. Activities of starter were investigated in terms of viable counts of microbes and change of pH and total titratible acidity Domestic wheat flours contain 100 times more number of lactic acid bacteria than yeast regardless of types of wheat flours. The more protein contents in wheat flours, the more stable microbes in starter. This was considered to be the result of buffering effect of wheat proteins. The optimum level of protein content to ensure the activity of starter was more than 12.0%. Optimum level of water content in active starter was 110% based on strong flour. The more water or the less water had the tendency of decreasing viable counts of microbes. Addition of salt and sucrose had increased the activity of starters. However oligosaccharides did not affect the activity of starter. The optimum concentrations of salt and sucrose were 1.0% and 5.0% respectively. Bread with the starter was higher scored than breads with yeast in terms of all the quality and sensory characteristics except their volumes. In conclusion, a starter formulated with strong flour 100%, water 110%, salt 1% and sucrose 5% was considered to have high potential as a substitute of yeast in making natural bread.

Changes in the Microflora of Marine Fishes during Storage by Partial Freezing (해산어(海産魚)의 부분동결(部分凍結)에 의한 Microflora의 변화(變化))

  • Park, Chan-Sung;Choi, Kyoung-Ho
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.15 no.1
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    • pp.56-62
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    • 1986
  • Marine fishes, sardine(Sardinops melanosticta), scad kingfish(Caranx equula), horse mackerel(Trachurus japonicus) and file fish(Navodon modestus), were stored for fifty days with partial freezing at$-3.5^{\circ}C$. During the storage, the changes in microflora and volatile nitrogen content was investigated. The fishes exhibited $10^4\;to\;10^6$ of bacterial cells per square centimeter of their skin just before they were submitted to the storage. The bacterial cell number was increased as $10^6\;to\;10^8$ cells as the storage time passed over twenty-two days. Offensive odor which is typical in the spoilage of fishes became strong as increase the bacterial cell numbe. The major isolates among the three hundred strains of bacteria isolated from the fish skins were identified as Pseudomonas I/II, III/IV-H, Vibrio and Moraxella. The same was found in the spoiled fishes, however, Pseudomonas I/II, was predominant on contrast to that of fresh fishes. Pseudomonas III/IV-NH, Flavobacterium, Cytophaga and Micrococcus were also found in early period of storage, but they disappeared as the progress of storage. Nine per cent of isolates were unidentified.

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