• Title/Summary/Keyword: yeast numbers

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Quality Characteristics of Rice Wine according to the Rice Wine Seed Mash with Lactic Acid Concentration (젖산농도별 주모에 따른 막걸리의 품질 특성)

  • Huh, Chang-Ki;Lee, Jung-Won;Kim, Yong-Doo
    • Food Science and Preservation
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    • v.19 no.6
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    • pp.933-938
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    • 2012
  • The quality characteristics of rice wine seed mash and rice wine made with different lactic acid concentrations were investigated. The pH decreased along with the lactic acid concentration. The total titratable acid content of the rice wine seed mash was lowest when 0.5% lactic acid was added, and the ethanol contents of the mash samples were not significant. The results of the measurement of the microorganism number, C (cell numbers of the total bacteria and the lactic acid bacteria), decreased along with the lactic acid concentrations of the mash samples. The yeast cell numbers of the rice wine seed mash samples according to the lactic acid concentrations were high (0.5, 0.3, 1.0, control, and 0.7%, respectively). The pH and total titratable acid levels of rice wine according to the lactic acid concentration were stable during fermentation, according to the increase in the amount of lactic acid. The organic acids in the rice wines were highest in the lactic acid. The rice wines to which lactic acid had been added had lower acetic acid contents than the control. Also, the acetic acid contents decreased along with the lactic acid concentrations, except in the rice wine treated with 1.0% lactic acid. The ethanol contents of the tested rice wines were not significant. All in all, in the sensory evaluation, the rice wines treated with 0.5 and 0.7% lactic acid scored higher than the other treatments.

Reduction of Microflora in the Manufacture of Saengshik by Hygienic Processing

  • Bang, Woo-Seok;Eom, Young-Rhan;Oh, Deog-Hwan
    • Preventive Nutrition and Food Science
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    • v.12 no.3
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    • pp.167-172
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    • 2007
  • This study was conducted to determine the effect of hygienic processing (HP) on the reduction of microorganisms during manufacturing of saengshik with two vegetables (carrots and cabbage) and two grains (barely and glutinous rice) compared to general processing (GP). For GP, distilled water was used for washing raw materials and equipment. For HP, aqueous ozone (3 ppm) in combination with 1% citric acid and 70% alcohol were used for washing raw materials and the equipment, respectively. In carrots, after cutting, total aerobic bacteria (TAB), yeast and mold (YM) and coliforms were significantly increased to 5.19, 8.04 and 2.08 ($log_{10}$ CFU/g), respectively (p<0.05). Washing effectively reduced the increased microorganisms from cross contamination during cutting, but cross contamination increased with subsequent GP drying and milling procedures to 8.56, 8.27 and 3.71 ($log_{10}$ CFU/g) for TAB, YM and coliforms, respectively (p<0.05). On the other hand, HP washing of carrots with 3 ppm ozone in combination with 1% citric acid showed higher antimicrobial effect than GP washing, significantly decreasing the number of microorganisms (p<0.05). Further cross contamination did not occur through drying and milling due to cleaning the equipments with 70% alcohol prior to processing. After milling, the number of TAB, YM and coliforms were significantly decreased to 3.89, 4.47 and not detectable level ($log_{10}$ CFU/g), respectively (p<0.05). Similar results were observed in cabbage and grains. During storage for two months at different temperatures (22 or $4^{\circ}C$), there were no changes in numbers of spoilage microorganisms in the packaged saengsik after either processing. This suggests the importance of HP for the reduction of microorganisms during saengsik production, and demonstrates the effectiveness of disinfection at each processing stage in minimizing contamination levels to enhance microbial safety of saengshik products.

Fermented Whey Produced by Mixed Culture of Lactobacillus acidophilus and Propionibacterium freudenreichii : Effect on Quality Properties of Bread (Lactobacillus acidophilus와 Propionibacterium freudenreichii로 혼합 배양한 Whey 발효물이 빵의 특성에 미치는 영향)

  • Yun Mi-Suk
    • The Korean Journal of Food And Nutrition
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    • v.18 no.2
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    • pp.109-114
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    • 2005
  • A mixed Lactobacillus acidophilus and Propionibacterium freudenreichii was cultured in the $10\%$ whey broth with $0.5\%$ yeast extract for 4 days. Viable cell numbers of Lactobacillus acidophilus and Propionibacterium freudenreichii were $2.4\ties10^9$ cfu/mL after 36hr and $9.42\times10^8$ cfu/mL after 96 hr. Consumption rate of lactose during fermentation was $87.5\%$. Propionic acid was produced 18.5g/L and acetic acid was produced 4.8g/L, as a result of that, comparison of propionic acid and acetic acid was 3.8:1 Volume of white pan bread was decreased as added amount of whey was increased. Hardess of white pan bread was decresed as added amount of whey was increased. Preservation period of white pan bread with $10\%$ whey fermented product elongated 2 day compared to control.

Quality and Shelf-life of Vacuum and Aerobic Packed Chevon Patties under Refrigeration

  • Rajkumar, V.;Agnihotri, M.K.;Sharma, N.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.4
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    • pp.548-553
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    • 2004
  • Patties were prepared using Barbari male goats meat (age about 4 yrs) and packed in HDPE under vacuum (VP) and aerobically (AP). Packed patties were stored at 4$\pm$1$^{\circ}C$ and evaluated for physico-chemical, microbiological and sensory changes on days 0, 5, 10, 15, 20 and 25. Overall mean water activity ($a_{w}$), moisture (%), fat (%), pH, TBA number and W-B shear force values (kg/$cm^{2}$) of patties were 0.983, 61.93, 18.39, 6.38, 0.150 and 0.86, respectively. Except pH that was significantly higher and TBA number significantly lower in VP patties, treatment had no significant (p>0.05) effect on other physico-chemical traits. However, storage period significantly (p<0.05) affected physico-chemical traits. Moisture (63.79%) and $a_{w}$ (0.985) were significantly (p<0.05) higher on day 25. Patties became firmer on day 20 onwards as indicated by higher W-B shear force. Though packaging method had no significant effect, storage period influenced microbial counts. The standard plate counts (SPC), which were initially log 5.98 CFU/g decreased significantly (p<0.05) on day 10 followed by steady increase and reaching log 4.89 on day 25. Almost similar trend was observed for psychrotrophic bacteria counts. Lactic acid bacteria counts declined as the storage period progressed. Coliforms, and yeast and mould counts were either not detected by the method used or were very low in numbers. All samples of AP patties revealed swollen, greasy and sticky surface with spongy texture on day 20 whereas only some of the VP patties shown such changes on day 20. Results indicated that vacuum packaging had definite advantage in preserving the sensory quality of patties than aerobic packaging but it did not help in extending the shelf-life beyond 15 days.

The Growth of L.acidophilus and B. bifidum in Fermented Milk Product (Lactobacillus acidophilus와 Bifidobacterium bifidum의 발효 유제품내의 성장)

  • 백현임;허태련
    • KSBB Journal
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    • v.6 no.4
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    • pp.413-424
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    • 1991
  • The optimal condition for manufacturing the yoghurt by using B. bifidum and L. acidophilus was studied. Optimal growth condition of B. bifidum and fermentation effects of B. bifidum, L. acidophilus and Str. thermophilus in mixed culture were investigated separately. Fermentation conditions of B. bifidum were optimized in 12% reconstitued skim milk. The addition of BIOS 2000 to 12% skimmilk was effective on the growth and acid production of B. bifidum. There was asymbiosis among B. bifidum, L. acidophilus and Str. thermophilus in mixed culture which resulted in higher viable cell numbers and acid production. The optimum production of yoghurt was achieved by incubation at $37^{\circ}C$ for 8 hours with 5% mixed starter culture (B. bifidum+L.acidophilus+Str. thermophilus). In this case the effective ratio of B. bifidum: L. acidophilus: Str. thermophilus was 2:1:1 on both acid production and viable cell counts.

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Analysis of Free Sugar, Organic Acid and Free Amino Acid in Commercial Makjang (시판 막장의 맛 성분에 관한 연구 -유리당, 유기산, 유리아미노산을 중심으로-)

  • Jeon, So Hean;Jeon, Hye Lyun;Kim, Hyun-Jeong;Lee, Su-Jin;Lee, Bo-Dam;Kim, Mee Ree
    • Journal of the East Asian Society of Dietary Life
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    • v.25 no.2
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    • pp.326-332
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    • 2015
  • Makjang is a kind of Korean traditional short-term fermented soybean paste. The purpose of this study was to evaluate the compositions of free sugars, organic acids and free amino acids as well as microbial counts of six kinds of Makjang. Commercial Makjang from different regions (Kangwon-do, Choongchung-do and Kyungsang-do) were used. The major free sugars of samples were glucose (0.15~3.97%) and maltose (0.01~0.54%), whereas sucrose (0.02%) was detected only in M4 and fructose only in M1 and M2. The major organic acids were citric acid (0.16~3.09%), malic acid (0.06~0.23%) and succinic acid (0.01~0.11%). The total content of free amino acids ranged from 0.02 to 8.74 mg/g, and major amino acids were detected in the order of glutamic acid, leucine, alanine and aspartic acid. Numbers of viable cells of bacteria as well as yeast and molds were $7.8{\times}10^4{\sim}4.8{\times}10^5$ and $8.1{\times}10^3{\sim}3.6{\times}10^4$, respectively. The results of the sensory evaluation showed that over-all preference of Kyungsang-do Makjang was higher than others. Consequently these results provide better information for standardizing and improving quality and functional activity of commercial Makjang.

Quality Characteristics of Takju, Yakju, and Spirit made from Phellinus linteus and Ginger (상황버섯국과 생강국으로 제조한 탁주, 약주, 증류주의 품질 특성)

  • Lee, Jeong-Hoon;Choi, Hee-Suk;Son, Heung-Soo;Lee, Yun-Hi;Noh, Jeang-Mi;Kim, Jae-Min;Jeong, Jae-Hong
    • Culinary science and hospitality research
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    • v.21 no.6
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    • pp.103-119
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    • 2015
  • This study was carried out to evaluate the quality of characteristics of Takju, Yakju, and spirit made from Bunkuk(flour), Phellinus linteus and Ginger kuk. The sacharogenic power of Nuruks and pH, brix, acidity, cell numbers of yeast, and alcohol content of Deotsuls were analysed; flavors, organic acids, and sensory evaluation of Takju, Yakju, and spirit were employed in the analysis of this current study. Results showed that the saccharogenic power of Phellinus linteus kuk after fermentation of Nuruks showed the highest level, and Phellinus linteus kuk and Ginger kuk showed the same level after dry Nuruks. During fermentation of Deotsuls, pH and brix decreased with increased fermentation time, while acidity increased with increased fermentation time. Cell numbers of yeast were found to be at the highest level in Phellinus linteus kuk on the first day of fermentation, and it was the same result in the final stage(p<0.05). Alcohol content increased with an increase in fermentation time, and showed no significant difference between control and test in the final stage of fermentation. In terms of analysis of flavor components, acetone and n-amyl alcohol were not detected in Takju, Yakju, and spirit. n-butanol was detected at the highest value, followed by i-amyl alcohol. Fusel oil was detected at the highest level in spirit fermented by Bunkuk. In analysis of organic acids, lactic acid showed the highest content followed by acetic acid. Very small amounts of acetic acid were detected in the spirit and other organic acids were not detected. In sensory evaluation, Takju, Yakju, and spirit made from Phellinus linteus kuk showed the highest score. As a result of this study, Phellinus linteus kuk presented the most desirable Nuruk in order to make Takju, Yakju, and spirit.

Fermentation and Microbial Characteristics of Korean Traditional Fermented Milk, Tarak (시판 막걸리로 제조한 전통발효유 타락의 발효 특성)

  • Jung, Jin-Kyoung;Ko, Seong-Hee;Oh, Se-Wook;Lim, Ji-Young;Chun, Tae-Hoon;Kim, SooA;Myoung, Kil-Sun;Jang, Sung Seek;Huh, Chul-Sung;Han, Young-Sook
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.44 no.4
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    • pp.602-609
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    • 2015
  • In this study, for modernization of Korean traditional fermented milk, Tarak was made using four kinds of commercial Makgeolli based on the ancient cookbook Suwoonjabbang. Samples of Tarak were periodically collected during 24 h of fermentation at $37^{\circ}C$. After fermentation, changes in pH, titration acidity, and viscosity were analyzed. Fermentation metabolites, including organic acids and free sugars, were analyzed by HPLC. Numbers of yeast and lactic acid bacteria during 24 h of fermentation were measured. The pH of Tarak significantly decreased (P<0.01), whereas its acidity significantly increased (P<0.01) during fermentation. The viscosity increased during 8~24 h of fermentation until curd was separated in Tarak. The level of ethanol increased from 0.37~0.52 mg/mL to 0.51~0.71 mg/mL during 24 h of fermentation. Lactic acid and lactose were the major organic acid and free sugar in Tarak, respectively. The number of lactic acid bacteria increased from 5.23~6.25 log CFU/mL to 9.87~10.41 log CFU/mL at the beginning during 24 h of fermentation. The number of yeast increased from 5.14~6.47 log CFU/mL to 6.99~7.73 at the beginning during 24 h of fermentation at $37^{\circ}C$. The major strains of Tarak were Pediococcus acidilactici, Lactobacillus fermentun, Lactobacillus curvatus, and Saccharomyces cerevisiae. Therefore, we concluded that Tarak was a fermented milk by both lactic acid bacteria and yeast, which was similar to koumiss or kefir.

Effect of Electrolyzed Water and Citric acid On Quality Enhancement and Microbial Inhibition in Head Lettuce (전해수와 구연산을 이용한 양상치의 품질 향상 및 미생물 저감화 효과)

  • Jin, Yong-Guo;Kim, Tae-Woong;Ding, Tian;Oh, Deog-Hwan
    • Korean Journal of Food Science and Technology
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    • v.41 no.5
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    • pp.578-586
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    • 2009
  • This study was conducted to determine the effects of alkaline electrolyzed water (AIEW), acidic electrolyzed water (AcEW), 1% citric acid, and 100 ppm sodium hypochlorite, either alone or in combination with citric acid, in reducing the populations of spoilage bacteria and foodborne pathogens (Listeria monocytogenes and Escherichia coli O157:H7) on lettuce at various exposure times (3, 5, and 10 min) with different dipping temperatures (1, 20, 40, and $50^{\circ}C$). In addition, the inhibitory effect of alkaline electrolyzed water combined with citric acid on the browning reaction during storage at $4^{\circ}C$ for 15 days was investigated. Compared to the untreated control, electrolyzed water more effectively reduced the number of total bacteria, mold, and yeast than 100 ppm sodium hypochlorite under the same treatment conditions. All treatments exposed for 5 min significantly reduced the numbers of total bacteria, yeast, and mold on head lettuce. The inactivation effect of each treatment on head lettuce was enhanced as the dipping temperature increased from 1 to $50^{\circ}C$, but there was no significantly difference at temperatures greater than $40^{\circ}C$ (p<0.05). The total counts of yeast and mold in head lettuce were completely eliminated when a combination of 1% citric acid and AlEW treatment was used at temperatures greater than $40^{\circ}C$. However, decreased reduction in L. monocytogenes (2.81 log CFU/g), and E. coli O157:H7 (2.93 log CFU/g) on head lettuce was observed under these treatment conditions. In addition, enhanced anti-browning effect was observed when the samples were subjected to both 1% citric acid and AlEW treatment at temperatures greater than $40^{\circ}C$ compared to when single treatments alone were used. Thus, this combined treatment might be considered a potentially beneficial sanitizing method for improving the quality and safety of head lettuce.

Comparison of Physicochemical and Organoleptic Characteristics of Omija Wines Made by Different Methods (제조방법에 따른 오미자 발효주의 이화학적 및 관능적 특성의 비교)

  • Lee, Sih-Yung;Kim, Myung-Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.2
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    • pp.182-187
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    • 2009
  • Physicochemical and organoleptic characteristics of omija wines made by traditional method, adding grape juice and sugar solution periodically, and with dry omija were compared. The pH values of all omija wines were ranged $2{\sim}3$ during fermentation. The acidity value of omija wine made by traditional method was 2.5%, that of omija wine made by adding grape juice and sugar solution periodically decreased from 3.3% to 0.8%, and that of omija wine made with dry omija increased from 0.2% to 3.9%. Sucrose and alcohol contents were $6.5{\sim}34.5^{\circ}Brix$ and 12% at the end of fermentation, respectively. The viable cell numbers of yeast decreased from $5.7{\sim}6.9\;\log\;CFU/mL$ to $4.3{\sim}4.6\;\log\;CFU/mL$. Omija wine made by adding grape juice and sugar solution periodically had the highest sensory scores for color, taste, flavor, swallowing, and overall acceptability, and was significantly different from the both omija wines made by traditional method and with dry omija. Because omija is rarely fermented due to the little fermentative sugar content, omija wine made by adding grape juice and sugar solution periodically was shown to be the most appropriate.