• Title/Summary/Keyword: Viable cell counts

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Changes in the Quality Characteristics and Antioxidant Activities of Yoghurts Containing Spirulina during Storage (스피루리나 첨가 요구르트의 저장 중 품질 특성 및 항산화능의 변화)

  • Son, Chan-Wok;Shin, Yu-Mi;Shim, Hyun-Jung;Kim, Min-Hee;Kim, Mi-Yeon;Lee, Kun-Jong;Kim, Mee-Ree
    • Journal of the East Asian Society of Dietary Life
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    • v.18 no.1
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    • pp.95-103
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    • 2008
  • The aim of this study was to evaluate the physicochemical, microbial, and sensory characteristics, as well as antioxidative activities of yoghurts containing spirulina powder, during storage at 4$^{\circ}C$. The pH of the yoghurts decreased until the 9th day of storage, but significantly increased by the 12th day. Total acidity also increased until the 9th day of storage, and then significantly decreased by the 12th day. Sugar content did not change significantly (approximately 18 $^{\circ}Brix$). Viscosity(cP) increased until the 6th day of storage, but had decreased at the 12th day. The viable bacterial cell counts of the control group decreased during storage. In contrast, the viable cell counts of the spirulina containing samples increased until the 9th day, and then decreased by the 12th day of storage. Antioxidant activity decreased in all groups, but the changes in antioxidant activity were lower in the spirulina groups than in the control group. According to sensory evaluations, the samples presented no significant differences during storage. Based on the above results, the optimum concentration of spirulina was determined as 0.25%. Also, the period of circulation of yoghurt containing spirulina was estimated to be 9 days at 4$^{\circ}C$.

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Effects of Red Pepper Powder Addition Times on Ethanol Production from Apple Gochujang Mash (고춧가루 첨가시기를 달리한 사과고추장혼합물의 에탄올 생성)

  • Oh, Chul-Hwan;Oh, Nam-Soon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.5
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    • pp.828-831
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    • 2013
  • Fermentation patterns of apple Gochujang mash prepared with different addition times of red pepper powder were investigated. Red pepper powder was added into Gochujang mash before and after fermentation of the mash. In the apple Gochujang mash without red pepper powder, viable yeast cell counts of Zygosaccharomyces rouxii Y-80 increased to 6.5 log CFU/g shortly after five days of fermentation, and ethanol concentration reached its maximum value (3.8% of the total volume) after 15 days of fermentation. On the other hand, in apple Gochujang mash prepared by the initial addition of red pepper powder before fermentation, viable yeast cell counts increased to 7 log CFU/g after 20 days of fermentation, and ethanol concentration reached 1.3% after 25 days of fermentation. Yeast growth and ethanol production were stimulated in the Gochujang mash without red pepper powder. Sensory evaluation scores were similar in the apple Gochujang regardless of addition time of red pepper powder.

Antibacterial Effects of Natural Essential Oils from Ginger and Mustard against Vibrio Species Inoculated on Sliced Raw Flatfish

  • Yoo, Mi-Ji;Kim, Yong-Suk;Shin, Dong-Hwa
    • Food Science and Biotechnology
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    • v.15 no.3
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    • pp.462-465
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    • 2006
  • In order to extend the shelf life of sliced raw flatfish, the antimicrobial effects of natural essential oil from mustard and a mixture of ginger and mustard essential oils were tested at various temperatures. In addition, volatile components of the mixed essential oils were analyzed using gas chromatography and gas chromatography mass spectrometry. The viable cell counts of Vibrio parahaemolyticus treated with mixed essential oils from ginger and mustard was 0.7-1.3 log CFU/g lower than those of other treatments during storage at $5^{\circ}C$. During storage at $20^{\circ}C$, the viable cell counts of V. parahaemolyticus, V. vulnificus 01, and V. vulnificus 02 treated with the essential oils increased slightly from 6.53-6.64 log CFU/g at initial stages to 6.77-7.72 log CFU/g after 24-hr of storage, however they were 1.38-1.97 log CFU/g lower than those of the control group (8.74-9.10 log CFU/g). These results show that the growth of V. parahaemolyticus and V. vulnificus inoculated on sliced raw flatfish could be inhibited by treatment with natural essential oils from ginger and mustard at $5^{\circ}C$ of storage. However, the antibacterial effects of the essential oils on Vibrio species observed in this study were not sufficient to merit their use in sliced raw flatfish at temperatures exceeding $20^{\circ}C$.

Safety Evaluation of Frozen Oyster Crassostrea gigas as a Raw Material for Seafood Products (시판 냉동굴(Crassostrea gigas)의 위생 안전성 평가)

  • Park, Sun Young;Cho, Hye Jeong;Lee, Seok Min;Heu, Min Soo;Kim, Jin-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.53 no.6
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    • pp.861-869
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    • 2020
  • This study was conducted to investigate the suitability of frozen oysters as a raw material for the preparation of seafood products by measuring the concentrations of harmful microorganisms and chemicals in thawed flesh. The microbial concentrations in thawed oysters were 2.3-5.0 log CFU/g for viable cell counts, not detected (ND)-1.0 log CFU/g for coliform bacteria, and ND for Escherichia coli and pathogenic bacteria such as Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Enterohemorrhagic Escherichia coli (EHEC), and Clostridium perfringens. In frozen oysters, the heavy metal concentration for viable cell counts was ND-0.030 mg/kg, for lead was ND-0.393 mg/kg, and for cadmium was 0.021-0.597 mg/kg. Benzo(a)pyrene, shellfish poison (paralytic shellfish and diarrhetic shellfish poisons), and radioactivity were not detected in the thawed oysters. These results suggest that frozen oysters can be safely used as a raw material for the preparation of seafood products.

Angiotensin-I-Converting Enzyme Inhibitory Peptides in Goat Milk Fermented by Lactic Acid Bacteria Isolated from Fermented Food and Breast Milk

  • Rubak, Yuliana Tandi;Nuraida, Lilis;Iswantini, Dyah;Prangdimurti, Endang
    • Food Science of Animal Resources
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    • v.42 no.1
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    • pp.46-60
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    • 2022
  • In this study, angiotensin-I-converting enzyme inhibitory (ACEI) activity was evaluated in fermented goat milk fermented by lactic acid bacteria (LAB) from fermented foods and breast milk. Furthermore, the potential for ACEI peptides was identified in fermented goat milk with the highest ACEI activity. The proteolytic specificity of LAB was also evaluated. The 2% isolate was inoculated into reconstituted goat milk (11%, w/v), then incubated at 37℃ until pH 4.6 was reached. The supernatant produced by centrifugation was analyzed for ACEI activity and total peptide. Viable cell counts of LAB and titratable acidity were also evaluated after fermentation. Peptide identification was carried out using nano liquid chromatography mass spectrometry (LC-MS/MS), and potential as an ACEI peptide was carried out based on a literature review. The result revealed that ACEI activity was produced in all samples (20.44%-60.33%). Fermented goat milk of Lc. lactis ssp. lactis BD17 produced the highest ACEI activity (60.33%; IC50 0.297±0.10 mg/mL) after 48 h incubation, viable cell counts >8 Log CFU/mL, and peptide content of 4.037±0.27/mL. A total of 261 peptides were released, predominantly derived from casein (93%). The proteolytic specificity of Lc. lactis ssp. lactis BD17 through cleavage on the amino acid tyrosine, leucine, glutamic acid, and proline. A total of 21 peptides were identified as ACEI peptides. This study showed that one of the isolates from fermented food, namely Lc. lactis ssp. lactis BD17, has the potential as a starter culture for the production of fermented goat milk which has functional properties as a source of antihypertensive peptides.

Lactobacillus bulgaricus Fermentation Characteristics of Yogurt with added Buckwheat Sprout (Lactobacillus bulgaricus를 이용한 메밀싹 첨가 요구르트의 발효특성)

  • Kang, Ha-Ni;Kim, Chul-Jai
    • Journal of the Korean Society of Food Culture
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    • v.24 no.1
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    • pp.90-95
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    • 2009
  • The principal objective of this study was to investigate the influence of buckwheat sprouts on the acid production and growth of lactic acid bacteria in to which 5 and 10%(w/v) buckwheat sprouts was added, followed by fermentation with Lactobacillus bulgaricus. In yogurt to which 5 and 10% buckwheat sprouts was added, pH was lower and titratable acidity was higher than those of the control. It was also noted significant changes in the number of viable cell counts with differing amounts of added buckwheat sprouts until 12 hours. When the yogurt samples were stored for 12 days at $4^{\circ}C$, the pH and titratable acidity of the yogurt to which 5 and 10% buckwheat sprouts was added were maintained at lower and higher than control levels, respectively. The highest number of viable cell counts was found in the yogurt to which 5% buckwheat sprouts was added. Rutin content was reduced via lactic acid fermentation, but quercetin content increased significantly in the yogurt with added buckwheat sprouts. It may be that the glycosidic bonds connected to rutin were hydrolyzed during fermentation by lactic acid bacteria. The total phenol compound content of the yogurt samples also increased after fermentation. The antioxidative activity of yogurt to which 10% buckwheat sprouts was added was shown to have a 60.95% free radical scavenging effect, which was the highest among all yogurt samples evaluated.

Improving the Shelf Life of Pork by using a Coating Agent with Mandarin Peel Powder (귤 과피 분말을 첨가한 피막제 처리에 의한 돈육의 저장성 향상)

  • Hyeonjeong Choi;Yong-Suk Kim
    • Journal of Food Hygiene and Safety
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    • v.38 no.2
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    • pp.55-62
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    • 2023
  • This study aimed to investigate the effect of a coating agent on pork storage. Pork was coated with a coating agent containing sodium carboxymethyl cellulose (CMC) and mandarin peel powder (M). The treatments were divided into control, a 0.1% CMC treatment, and a 0.1% CMC +5% M treatment, and pH, color, 2-thiobarbituric acid reactive substances (TBARS), volatile basic nitrogen (VBN), and the number of viable cell counts were measured. In the case of redness (a), it was found that the reduction over the storage period was less in the 0.1% CMC + 5% M treatment than in the control and the 1% CMC treatment. When stored at 4℃ and 25℃, TBARS of pork tended to increase during the storage period, followed by control, 0.1% CMC treatment, and 0.1% CMC + 5% M treatment, indicating that lipid oxidation was most suppressed in pork coated with mandarin peel powder. As a result of measuring the VBN of pork stored at 4℃ and 25℃, the 0.1% CMC + 5% M treatment showed lower values than the control and 0.1% CMC treatment. When the film-coated pork was stored at 4℃, the number of viable cell counts in the 0.1% CMC +5% M treatment area was 7.13±0.96 log CFU/g on the 12th day of storage, delaying the growth of viable cell counts for approximately 3 d more than other treatments. Therefore, coating pork with a film containing CMC and mandarin peel powder has been confirmed to delay the increase in the number of viable cell counts while reducing the quality change during pork storage, which is an effective alternative to improving the storage of fresh food as an edible film.

Long-Term Starvation Induces the Viable-but-Nonculturable Condition in Lactobacillus crispatus KLB46

  • Lee, Seok-Yong;Kim, Ju-Hyeon;Jang, Jeong-Eun;Kim, Seung-Cheol;Yun, Hyeon-Sik;So, Jae-Seong
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.918-922
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    • 2001
  • In a previous study, we have isolated a number of lactobacilli from Korean women, and one of them (KLB46) was identified as Lactobacillus crispatus by 16S rRNA gene sequencing. For the ecological treatment of bacterial vaginosis (BV) cell suspension of L. crispatus KLB46 was instillated into BV patients. L. crispatus KLB46 was found to persist for several days in cell suspension with no nutrients. In this study, in order to assess the influence of starvation on physiological activity, we compared the viability and culturability of KLB46 following suspension in various buffer solutions. A pair of in situ fluorescent dye was used to assess viability (i.e. membrane integrity) and the culturability was examined by plate count assay. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit $(BacLight^{TM})$ was applied to estimate both viable and total counts of bacteria in cell suspension. $BacLight^{TM}$ is composed of two nucleic acid-binding stains ($SYTO\;9^{TM}$ and propidium iodide). $SYTO\;9^{TM}$ penetrates all bacterial membranes and stains the cells green while propidium iodide only penetrates cells with damaged membranes, therefore the combination of the two stains produces red fluorescing cells. Optimal staining conditions for $BacLight^{TM}$ were found to be with 0.0835M $SYTO\;9^{TM}$ and 0.05M propidium iodide for 15 min incubation at room temperature in dark. When cells were microscopically examined during 140 hours of starvation, the culturability decreased markedly while the viability remained relatively constant, which suggests that large fraction of KLB46 cells became viable but non-culturable (VBNC) upon starvation.

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Studies on the Processing of Rapid- and Low Salt-Fermented Liquefaction of Sardine (Sardinops melanoslicta)(I) -Changes in Quility during Preheating of Chopped Whole Sardine and Optimum Conditions of Crude Enzyme Activity in Viscera- (저식염 속성 정어리 발효 액화물 가공에 관한 연구(I) -효소의 최적활성조건 및 마쇄육 예열처리중의 품질변화-)

  • Park, Choon-Kyu
    • Journal of the Korean Society of Food Culture
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    • v.14 no.5
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    • pp.455-460
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    • 1999
  • In order to establish the processing condition of salt-fermented liquefaction of sardine (Sardinops melanoslicta), effect of temperature, pH value, and concentration of salinity on crude enzyme activity of sardine viscera were investigated. The optimum temperature range of crude enzyme activity in sardine viscera was $45{\sim}50^{\circ}C$ and the optimum pH value of it was 9.8. According to the concentration of salinity increased the crude enzyme activity in sardine viscera decreased. The relationship between concentration of salinity (X) and the crude enzyme activity (Y) in sardine viscera is shown as follows; Y=-0.01363X+0.7676 (r=-0.88). For the purpose of processing conditions of rapid- and low salt-fermented liquefaction of sardine, changes of viable cell count, histamine content, and volatile basic nitrogen (VBN) in the chopped whole sardine with 8% NaCl during preheating process at $40^{\circ},\;45^{\circ}$ and $50^{\circ}C$ for 48 hrs were analyzed. During preheating, initial viable cell counts of chopped whole sardine were $10^{4-7}/g$, but they decreased $10^{1-5}/g$ after 48 hrs. Histamine contents during preheating process at $40^{\circ}\;and\;45^{\circ}C$ were gradually increased, whereas at $50^{\circ}C$ were almost the same level after 48 hrs. VBN contents were continuously increased during preheating, but preheating at $50^{\circ}C$ samples were lower level than that of $40^{\circ}\;and\;45^{\circ}C$ ones. For the purpose to accelerate the fermentation and liquefaction of chopped whole sardine, preheating at optimum temperature of crude enzyme activity for 48 hrs was useful processing method and the contents of viable cell count, histamine, and VBN were safety level for food sanitation.

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Characteristics of fermented milk containing Bifidobacterium growth promoter (BE0623) and dietary fiber

  • Cho, Young Hoon;Sim, Jae Young;Nam, Myoung Soo
    • Korean Journal of Agricultural Science
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    • v.48 no.2
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    • pp.209-218
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    • 2021
  • This study was carried out to investigate the effects of Bifidobacteria growth promoter BE0623 and a dietary fiber supplement, which included Bifidobacterium lactis BB12, Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium lactis. In fermented milk containing BE0623, the viable cell count of Bifidobacteria significantly increased by about 45 to 75 times compared to the control, and the titratable acidity increased, whereas the pH decreased. All fractions obtained by isolating BE0623 had Bifidobacteria growth effect. Acacia dietary fiber is a pale yellow powder. It has a viscosity of 60 to 100 cPs and a pH between 4.1 and 5.0. Its general components are less than 10% moisture, more than 90% dietary fiber, and less than 4% ash. The optimal addition ratio of Bifidobacteria growth promoting material was determined to be 0.05%. The general components of the manufactured fermented milk were carbohydrate 17.85%, protein 3.63%, fat 3.00%, and dietary fiber 2.95%. During storage of the fermented milk for 24 days, its titratable acidity, viscosity, and sugar content all met the criteria. In addition, the viable cell counts of Bifidobacteria and lactic acid bacteria in the fermented milk were 1.7 × 108 CFU·mL-1 and 1.5 × 107 CFU·mL-1, respectively, and Escherichia coli was negative. There was no significant difference between the control group and the treatment group in the sensory evaluation of sweet, sour, weight, and flavor, and the preference for the treatment group was excellent. The acceptability of the fermented milk of the treated group according to the storage period was excellent in terms of color, flavor, and appearance.