• Title/Summary/Keyword: post-acidification

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Effect of Encapsulated Bacteriocin on Acid Production and Growth of Starter Cultures in Yoghurt

  • Oh, Se-Jong;Heo, Ho-Jin;Park, Dong-June;Kim, Sae-Hun;Lee, Sung-Je;Imm, Jee-Young
    • Food Science and Biotechnology
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    • v.15 no.6
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    • pp.902-907
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    • 2006
  • Freeze dried crude bacteriocin was encapsulated within an acid-soluble coating material, Eudragit EPO, using a surface modification technique through a hybridization system. The pH and titratable acidity of control yoghurt were 3.92 and 1.56%, respectively, after 24 hr of fermentation at $42^{\circ}C$, whereas yoghurt containing 500 AU/mL encapsulated bacteriocin exhibited a higher pH (4.37) and lower titratable acidity (1.2%). Yoghurt containing encapsulated bacteriocin had significantly lower titratable acidity when the duration of fermentation (to pH 4.5) and subsequent refrigerated storage ($4^{\circ}C$) was longer than 20 days. There were no significant differences in the viability of lactic acid bacteria after 15 hr of fermentation. This suggests that microencapsulated bacteriocin has the potential to control the excessive growth of yoghurt starters caused by temperature abuse or post-acidification.

Effects of Yeast Growth Inhibiting and Yogurt Quality Improving with Lactobacillus paracasei and Lactobacillus rhamnosus (Lactobacillus paracasei와 Lactobacillus rhamnosus를 이용한 요구르트의 효모 성장 억제와 품질 향상 효과)

  • Kim, Chul-Hong;Nam, Myoung Soo
    • Journal of Life Science
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    • v.26 no.12
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    • pp.1438-1445
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    • 2016
  • Yeast can be post-contaminated by the equipment, producer, or air, and this can degrade yogurt quality. This study aimed to demonstrate the yeast inhibiting effect in fermented milk by adding Lactobacillus paracasei and Lactobacillus rhamnosus along with current fermenting lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. A certain amount of yeast was added to fermented milk samples that were soon after stored at variable temperatures, and the number of yeast cells was counted periodically. The swelling phenomenon caused by the gas produced by the yeast in fermented products was also observed. In the two experiments, compared to the control, the L. paracasei- and L. rhamnosus-added-groups showed much slower rate of yeast appearance and lower frequency of swelling phenomena. This suggests that using a mixture of L. paracasei and L. rhamnosus in fermented milk inhibits the growth of yeast. Furthermore, if the products are stored at $10^{\circ}C$, post-acidification is rarely seen in the experimental group compared to the control group. This means that the organoleptic flavor can be kept consistent from the production day till the expiration day, resulting in improved organoleptic quality for customers. In other words, the use of L. paracasei and L. rhamnosus in fermented milk will result in the following positive effects: improvement in storage stability by delaying yeast appearance, increase in quality consistency by inhibiting post-acidification, and improved organoleptic quality by enhancing texture and flavor.

Erythropoietic Activity in Plasma of Chronic Post-hemorrhagic Anemic Men (만성 실혈성 빈혈자 혈장의 적혈구조혈 작용)

  • Kim, Wan-Tai;Chung, Kwan-Ogg;Kim, Yoon-Sun;Cho, Yong-Moon;Chung, Won-Keun;Nam, Kee-Yong
    • The Korean Journal of Physiology
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    • v.4 no.1
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    • pp.55-57
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    • 1970
  • Erythropoietic activity in anemic Plasma of chronic posthemorrhagic anemic men was studied in rats after subcutaneous injection of anemic plasma. Anemic plasma was obtained from blood donors who sold their blood once or twice a week for one or two years to blood bank. Hemoglobin concentrations of 8 blood donors ranged between 4.6 and 8.4 gm/100 ml. Pooled plasma was treated by acidification-boiling method and adjusted to pH 7.5 by adding 0.1 N NaOH. 7ml/kg and 15ml/kg of anemic plasma filtrate was injected to 2 groups of rats respectively for 7 and 8 days. Hemoglobin concentrations, red blood cell counts and reticulocyte counts were observed before and after injection of anemic plasma and no change was induced by the injection. Subsequently, it was concluded that there was no erythropoietin of high titer in the plasma of chronic post-hemorrhagic anemic men.

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Status and Implications of Regulatory Frameworks for Environmental Management of Geologic CO2 Storage in USA and EU (이산화탄소 지중저장의 환경 관리를 위한 미국과 유럽연합의 법·제도 현황과 시사점)

  • Jang, Eunseon;Yun, Seong-Taek;Choi, Byoung-Young;Chung, David;Kang, Hun
    • Journal of Soil and Groundwater Environment
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    • v.17 no.6
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    • pp.9-22
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    • 2012
  • Though geologic storage of $CO_2$ (GS) is considered as an attractive technological option to enormously reduce greenhouse gases emission into the atmosphere, many concerns on potential environmental and health risks associated with $CO_2$ leakage have been raised. In particular, groundwater contamination due to the brine displacement by a pressure build-up and the acidification by leaked $CO_2$ is paid a special attention. Therefore, integrated regulatory frameworks have been established by law in many countries to secure the permanent containment of injected $CO_2$. Regulatory frameworks deal with entire processes of GS, including site selection, monitoring and post-closure environmental management. This review paper provides a summary of regulatory frameworks in USA (U.S. EPA Geologic Sequestration Rule) and EU (Geologic $CO_2$ Sequestration Directive). The regulatory framework to properly address environmental issues should be established for the deployment of CCS projects in Korea.

Hydrogeology and Water Chemistry of the Friar Tuck Abandoned Coal Mine Site, Indiana, USA (미국 인디아나주 Friar Tuck 폐탄광의 수리지질 및 수질)

  • Park, Jung-Chan
    • Journal of the Korean Society of Groundwater Environment
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    • v.3 no.2
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    • pp.70-79
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    • 1996
  • The Friar Tuck Abandoned Coal Mine site is one of the most complexly disturbed areas in the midwestern United States. The deposits of gob and tailings contain high concentrations of pyrite, whose oxidation contributes to the acidification of soil and water and prevents the growth of vegetation. In an effort to quantitatively evaluate the effects of reclamation techniques, detailed monitoring program was performed. Water samples were collected from surface water, groundwater, and pore water from the unsaturated zone during a period of five years. According to the results, The spoil deposits are a relatively minor source of contamination and gob piles are the source of severe contamination to surface water and groundwater. But, loess and till beneath the gob piles effectively prevent the contaminated water migration from the source. Surface layers of the gob piles and the tailing deposits are less toxic than the interior of the deposits as a consequence of weathering over several decades. Acid mine drainage is in a post-peak stage and acid formation potential is probably situated in the unsaturated zone of refuse.

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Characterization and ACE Inhibitory Activity of Fermented Milk with Probiotic Lactobacillus plantarum K25 as Analyzed by GC-MS-Based Metabolomics Approach

  • Zhang, Min;Jiang, Yunyun;Cai, Miao;Yang, Zhennai
    • Journal of Microbiology and Biotechnology
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    • v.30 no.6
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    • pp.903-911
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    • 2020
  • Addition of probiotics to yogurt with desired health benefits is gaining increasing attention. To further understand the effect of probiotic Lactobacillus plantarum on the quality and function of fermented milk, probiotic fermented milk (PFM) made with probiotic L. plantarum K25 and yogurt starter (L. delbrueckii ssp. bulgaricus and Streptococcus thermophilus) was compared with the control fermented milk (FM) made with only the yogurt starter. The probiotic strain was shown to survive well with a viable count of 7.1 ± 0.1 log CFU/g in the PFM sample after 21 days of storage at 4℃. The strain was shown to promote formation of volatiles such as acetoin and 2,3-butanediol with milk fragrance, and it did not cause post-acidification during refrigerated storage. Metabolomics analysis by GC-MS datasets coupled with multivariate statistical analysis showed that addition of L. plantarum K25 increased formation of over 20 metabolites detected in fermented milk, among which γ-aminobutyric acid was the most prominent. Together with several other metabolites with relatively high levels in fermented milk such as glyceric acid, malic acid, succinic acid, glycine, alanine, ribose, and 1,3-dihydroxyacetone, they might play important roles in the probiotic function of L. plantarum K25. Further assay of the bioactivity of the PFM sample showed significant (p < 0.05) increase of ACE inhibitory activity from 22.3% at day 1 to 49.3% at day 21 of the refrigerated storage. Therefore, probiotic L. plantarum K25 could be explored for potential application in functional dairy products.

Quality and storage characteristics of yogurt containing Lacobacillus sakei ALI033 and cinnamon ethanol extract

  • Choi, Yu Jin;Jin, Hee Yeon;Yang, Hee Sun;Lee, Sang Cheon;Huh, Chang Ki
    • Journal of Animal Science and Technology
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    • v.58 no.4
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    • pp.16.1-16.7
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    • 2016
  • Background: This study was conducted to examine the quality and storage characteristics of yogurt containing antifungal-active lactic acid bacteria (ALH, Lacobacillus sakei ALI033) isolated from kimchi and cinnamon ethanol extract. The starter was used for culture inoculation (1.0 % commercial starter culture YF-L812 and ALH). Results: The antifungal activity of cinnamon extracts was observed in treatments with either cinnamon ethanol extracts or cinnamon methanol extracts. Changes in fermented milk made with ALH and cinnamon extract during fermentation at $40^{\circ}C$ were as follows. The pH was 4.6 after only 6 h of fermentation. Titratable acidity values were maintained at 0.8 % in all treatment groups. Viable cell counts were maintained at $4{\times}10^9CFU/mL$ in all groups except for 1.00 % cinnamon treatment. Sensory evaluations of fermented milk sample made with ALH and 0.05 % cinnamon ethanol extract were the highest. Changes in fermented milk made with ALH and cinnamon ethanol extract during storage at $4^{\circ}C$ for 28 days were as follows. In fermented milk containing ALH and cinnamon ethanol extracts, the changes in pH and titratable acidity were moderate and smaller compared with those of the control. Viable cell counts were maintained within a proper range of $10^8CFU/mL$. Conclusions: The results of this study suggest that the overgrowth of fermentation strains or post acidification during storage can be effectively delayed, thereby maintaining the storage quality of yogurt products in a stable way, using cinnamon ethanol extract, which exhibits excellent antifungal and antibacterial activity, in combination with lactic acid bacteria isolated from kimchi.

Changes in expression of monocarboxylate transporters, heat shock proteins and meat quality of Large White Yorkshire and Ghungroo pigs during hot summer period

  • Parkunan, Thulasiraman;Das, Arun K.;Banerjee, Dipak;Mohanty, Niharika;Paul, Avishek;Nanda, P.K.;Biswas, TK;Naskar, Syamal;Bag, Sadhan;Sarkar, Mihir;Mohan, Narayana H.;Das, Bikash Chandra
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.2
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    • pp.246-253
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    • 2017
  • Objective: Present study explores the effect of hot summer period on the glycolytic rate of early post-mortem meat quality of Ghungroo and Large White Yorkshire (LWY) pig and comparative adaptability to high temperature between above breeds by shifting the expression of stress related genes like mono-carboxylate transporters (MCTs) and heat shock proteins (HSPs). Methods: Healthy pigs of two different breeds, viz., LYW and Ghungroo (20 from each) were maintained during hot summer period (May to June) with a mean temperature of about $38^{\circ}C$. The pigs were slaughtered and meat samples from the longissimus dorsi (LD) muscles were analyzed for pH, glycogen and lactate content and mRNA expression. Following 24 h of chilling, LD muscle was also taken from the carcasses to evaluate protein solubility and different meat quality measurements. Results: LWY exhibited significantly (p<0.01) higher plasma cortisol and lactate dehydrogenase concentration than Ghungroo indicating their higher sensitivity to high temperature. LD muscle from LWY pigs revealed lower initial and ultimate pH values and higher drip loss compared to Ghungroo, indicating a faster rate of pH fall. LD muscle of Ghungroo had significantly lower lactate content at 45 min postmortem indicating normal postmortem glycolysis and much slower glycolytic rate at early postmortem. LD muscle of LWY showed rapid postmortem glycolysis, higher drip loss and higher degrees of protein denaturation. Ghungroo exhibited slightly better water holding capacity, lower cooking loss and higher protein solubility. All HSPs (HSP27, HSP70, and HSP90) and MCTs (MCT1, MCT2, and MCT4) in the LD muscle of pigs inclined to increase more in Ghungroo than LWY when exposed to high temperature. Conclusion: Effect of high temperature on the variation of HSPs and MCTs may play a crucial role in thermal tolerance and adaptation to different climatic conditions, pH regulation, muscle acidification, drip loss, protein denaturation and also in postmortem meat quality development.