scholarly journals Modelos cinéticos sigmoidales aplicados al crecimiento de Saccharomyces boulardii

2021 ◽  
Vol 23 (1) ◽  
pp. 47-54
Author(s):  
Alex Danny Chambi Rodriguez ◽  
◽  
Ana Mónica Torres Jiménez ◽  
Keyword(s):  
Culture Media ◽  
Titratable Acidity ◽  
Weibull Model ◽  
Saccharomyces Boulardii ◽  
Logarithmic Scale ◽  
Predictive Microbiology ◽  
Colony Forming Units ◽  
Sigmoidal Model ◽  
Growth Constants ◽  
Statistical Criteria

Predictive microbiology is an interesting tool that allows evaluating the behavior of biomass and metabolites in different culture media, providing multiple benefits, whether scientific or industrial, for these and other reasons the objective of this research was to evaluate applied sigmoidal kinetic models to the growth of Saccharomyces boulardii in milk. For this purpose, flasks were prepared with 200 mL of fresh cow's milk, previously sterilized at 121 ° C x 15 min, then the strains were inoculated at a temperature of 37 ° C and incubated at the same temperature under constant shaking of 20 revolutions per minute (rpm) in a water bath with shaking, for 7 h; To construct the curves and obtain the growth constants, colony-forming units were counted per milliliter (cfu / ml) at one-hour intervals, with a monocular microscope and Neubauer chamber. Also, the pH and titratable acidity expressed in lactic acid were measured. The data obtained were converted to a logarithmic scale to apply the sigmoidal equations of Gompertz, Logistic, Modified Logistic and Weibull. The results of the kinetic modeling gave us that the modified Logistics and Logistics models presented a better fit compared to the rest. Likewise, the Weibull model presented the lowest value of adjustment, on the other hand, in the analysis of the statistical criteria, all models except Weibull present similarity. Finally, each sigmoidal model allowed to evaluate the growth of Saccharomyces boulardii with each of its kinetic constants.

Modeling the Inactivation of Bacillus cereus in Tiger Nut Milk Treated with Cold Atmospheric Pressure Plasma

2019 ◽  
Vol 82 (11) ◽  
pp. 1828-1836 ◽  
Author(s):  
ALIYU IDRIS MUHAMMAD ◽  
RUILING LV ◽  
XINYU LIAO ◽  
WEIJUN CHEN ◽  
DONGHONG LIU ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Atmospheric Pressure ◽  
Treatment Time ◽  
Atmospheric Pressure Plasma ◽  
Titratable Acidity ◽  
Weibull Model ◽  
Input Power ◽  
Inactivation Kinetics ◽  
Pressure Plasma ◽  
Cold Atmospheric Pressure Plasma

ABSTRACT The impact of cold atmospheric pressure plasma treatment on the inactivation kinetics of Bacillus cereus ATCC 14579 and the resulting quality changes was investigated in tiger nut (Cyperus esculentus L.) milk (TNM). The effect of input power (39, 43, and 46 W) and treatment time (0 to 270 s) was fitted using the Weibull model to represent the microbial kinetic inactivation in the treated TNM. Inactivation efficacy increased with an increase in treatment time and input power. A 5.28-log reduction was achieved at 39 to 46 W without significant changes in titratable acidity, whereas no reduction in titratable acidity was observed in the pasteurized sample. The inactivation kinetics was adequately described by the Weibull model. Higher input power of 43 and 46 W and 120 s of treatment resulted in marked decreases in pH, flavonoid concentration, and antioxidant activity compared with those parameters in pasteurized TNM. Increases in total color difference and phenolic concentrations also were observed. The results indicate that these changes were caused by the immanent plasma reactive species. This study provides valuable inactivation kinetics information for food safety assessment studies of B. cereus vegetative cells in TNM.

scholarly journals Flavor and Other Quality Factors of Enzyme-peeled Oranges Treated with Citric Acid

HortScience ◽  
2007 ◽  
Vol 42 (7) ◽  
pp. 1644-1650 ◽  
Author(s):  
Simona Pinnavaia ◽  
Emilio Senesi ◽  
Anne Plotto ◽  
Jan A. Narciso ◽  
Elizabeth A. Baldwin
Keyword(s):  
Citric Acid ◽  
Bacterial Growth ◽  
Titratable Acidity ◽  
Taste Panel ◽  
Enzyme Treatment ◽  
Quality Factors ◽  
Microbial Counts ◽  
Aroma Volatiles ◽  
Colony Forming Units ◽  
Methyl Butanoate

Oranges can be satisfactorily processed for fresh slices using a process of enzyme infiltration under vacuum. Scored ‘Valencia’ and ‘Hamlin’ oranges were placed under 90 kPa vacuum in water, 1% citric acid (CA), or 1000 ppm pectinase (Ultrazym) at 30 °C for 2 min followed by 30 min incubation in air. After peeling, fruit were washed, cut, and all but CA-infused slices were dipped in water or 1% CA for 2 min. Drained slices were placed in sealed 454-mL deli containers and stored at 5 °C for up to 21 days. All ‘Valencia’ slices had microbial counts less than 1.0 log cfu·g−1 (cfu = colony-forming units) after 7 days storage, and slices from CA-infused fruit had less than 1.0 log cfu·g−1 after 21 days storage. For ‘Hamlin’, CA dips controlled bacterial growth on slices from water-infused oranges, except at 14 days. Enzyme-infused oranges resulted in slices with lower counts for both cultivars. CA-treated sliced (post enzyme treatment or by infusion) oranges had higher titratable acidity initially (‘Hamlin’) and after 14 days (‘Valencia’). When presented to a taste panel, ‘Valencia’ slices from enzyme-peeled fruit were preferred for texture after 2 days and 8 days in storage. In contrast, slices from fruit infused with water or citric acid were least preferred, were firmer, and had thicker segment membranes. Appearance of enzyme-treated fruit was preferred for ‘Hamlin’ oranges. Enzyme treatments increased levels of aroma volatiles, methanol and methyl butanoate, in ‘Hamlin’ slices, but overall sensory flavor data were unaffected.

scholarly journals Reduction of Microbial Populations on Prunes by Vapor Phase Hydrogen Peroxide

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 815F-815
Author(s):  
Gilbert F. Simmons ◽  
Joseph L. Smilanick ◽  
Shama John ◽  
Dennis A. Margosan
Keyword(s):  
Hydrogen Peroxide ◽  
Vapor Phase ◽  
Culture Medium ◽  
Culture Media ◽  
Microbial Populations ◽  
Plate Count ◽  
Potassium Sorbate ◽  
Plate Count Agar ◽  
Colony Forming Units ◽  
Aerobic Plate Count

Moisture is raised in dehydrated prunes to improve palatability before packaging and potassium sorbate is added to inhibit microbial growth. Vapor phase hydrogen peroxide (VPHP) technology uses hydrogen peroxide pulses to disinfect dried prunes. Dried prunes were obtained from dehydrators. The number of colony-forming units per 10 prunes (cfu/p) was compared between untreated and VPHP treated. Three culture media—dichloran rose bengal chloramphenicol agar base (DRBC, Oxoid), aerobic plate count agar (PCA), and potato dextrose agar (PDA)—were used to evaluate cfu/p. Similar mean microbe populations were observed on DRBC (67) and PDA (70); PCA had higher cfu/p (99). Microbes washed from untreated prunes obtained from dehydrators were 58 to 112 cfu/p, depending on the culture medium used. The number of cfu/p assessed on all media on VPHP-treated prunes was near 0 after 100 min exposure. Unlike potassium sorbate, hydrogen peroxide is a microbiocide rather than a microbiostat.

scholarly journals PROXIMATE AND SHELF LIFE EVALUATION OF SOYMILK YOGHURT WITH ADDED SACCHAROMYCES BOULARDII

2021 ◽  
Vol 9 (08) ◽  
pp. 1099-1108
Author(s):  
Okafor S.O. ◽  
◽  
Anyalogbu E.A. ◽  
Keyword(s):  
Shelf Life ◽  
Proximate Composition ◽  
Starter Culture ◽  
Titratable Acidity ◽  
Streptococcus Thermophilus ◽  
Saccharomyces Boulardii ◽  
Lactobacillus Bulgaricus ◽  
Fermentation Time ◽  
Life Evaluation ◽  
Water Holding

The effect of adding Saccharomyces boullardii in soya yoghurt was studied. The control was made with soya milk and traditional starter culture (Lactobacillus bulgaricus and Streptococcus thermophilus) while the other three treatments were made by adding 1%, 2%, 3% of S. boulardii with traditional yoghurt starter. Proximate composition of all yoghurt treatments were determined after fermentation time. Shelf-life evaluation of yoghurt treatment were observed during the storage time. During the proximate composition evaluation, treatment with 3% S. boulardii had highest moisture and protein content at 83.43±0.03 and 92±0.3 but least ash and carbohydrate content at 1.2±0.18 and 4.27±0.3. During shelf-life evaluation, titratable acidity and syneresis values of yoghurt with S. boulardii were slightly increased while pH and water holding capacity decreased compared with control yoghurt. After 21 days, S. boulardii counts were 5.89, 6.07 and 6.03 log.cfu/ml for yoghurt with 2% and 3% S. boulardii respectively whereas L. bulgaricus and S. thermophilius of yoghurt with 3% S. boulardii were 7.45 and 8.38 log.cfu/ml respectively. The addition of S. boulardii improved the survivability of the bacteria starter culture.

A comparison of a linear and proportional hazards approach to analyse discrete longevity data in dairy cows

2000 ◽  
Vol 70 (2) ◽  
pp. 197-206 ◽  
Author(s):  
R. Lubbers ◽  
S. Brotherstone ◽  
V.P. Ducrocq ◽  
P.M. Visscher
Keyword(s):  
Discrete Time ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Weibull Model ◽  
Logarithmic Scale ◽  
Data Set ◽  
Breeding Values ◽  
Hazards Model ◽  
Estimated Breeding Values ◽  
The Uk

AbstractThe objective of this study was to compare two methods for analysis of longevity in dairy cattle. The first method, currently used for routine genetic evaluation in the UK, uses a linear model to analyse lifespan, i.e. the number of lactations a cow has survived or is expected to survive. The second method was based on the concept of proportional hazard, i.e. modelling the conditional survival probability of a cow as a function of time. Comparisons were based on estimated heritabilities, ranking of estimated breeding values of sires, estimated effects of covariates used in the final models, and the distribution of residuals. The same data set, 21497 observations on the number of lactations cows had survived, was used for both analyses, even in the presence of censored observations. Cows in the data were progeny of 487 sires. Heritability estimates for lifespan or survival were approximately 0·06 for both methods, using the definition of heritability on a logarithmic scale for the proportional hazards model. Correlations between breeding values for sires were high, with absolute values ranging from 0·93 to 0·98, depending on the model fitted. It was concluded that it may be justified to use the standard Weibull model even for discrete time measures such as the number of completed lactations, but that more research is needed in the area of discrete time variates.

scholarly journals Development and maturation of mango fruits cv. ‘Ubá’ in Visconde do Rio Branco, Minas Gerais State, Brazil

Revista CERES ◽  
2018 ◽  
Vol 65 (6) ◽  
pp. 507-516
Author(s):  
Danielle Fabíola Pereira da Silva ◽  
Luiz Carlos Chamhum Salomão ◽  
Laísse Danielle Pereira ◽  
Karminne Dias do Valle ◽  
Hildeu Ferreira da Assunção ◽  
...  
Keyword(s):  
Soluble Sugars ◽  
Titratable Acidity ◽  
Dry Mass ◽  
Soluble Solids ◽  
Co2 Production ◽  
Solute Leakage ◽  
Fruit Skin ◽  
Minas Gerais State ◽  
Sigmoidal Model ◽  
Climacteric Stage

ABSTRACT Several criteria have been used to determine fruit maturity, which are based on the appearance and chemical composition of the produce at harvest time. The objective of this study was to evaluate the physical, chemical and physiological changes that occur during the development of mango cv. ‘Ubá’, aiming to determine the stages of fruit development until complete maturation. The experiment was carried out in an approximately 30-year-old orchard in Visconde do Rio Branco, MG (21º00'37"S, 42º50'26"W and 352 m altitude). Weekly, 25 fruits of 15 hoses were collected from the anthesis to the complete maturation in the plant. Samplings took place from August 2007 to January 2008. The characteristics evaluated were length, smaller and larger diameter; CO2 production; color parameters L*, a*, and b* of skin and pulp; fresh and dry mass (fruit, skin, pulp, and seed); solute leakage; pulp firmness; soluble solids (SS); titratable acidity (TA); SS/TA ratio; Vitamin C; carotenoids, starch, and soluble sugars. The development of mango fruit cv. ‘Ubá’ took 23 weeks. The developmental pattern fit a simple sigmoidal model. Fruits attached to the plant reached the respiratory climacteric stage between 20 and 21 weeks after anthesis.

Beet and orange mixed juices added with Lactobacillus acidophilus

2018 ◽  
Vol 48 (1) ◽  
pp. 76-87 ◽  
Author(s):  
Maria Rita Alaniz Porto ◽  
Vivian Sayuri Okina ◽  
Tatiana Colombo Pimentel ◽  
Sandra Garcia ◽  
Sandra Helena Prudencio
Keyword(s):  
Antioxidant Activity ◽  
Lactobacillus Acidophilus ◽  
Purchase Intention ◽  
Culture Media ◽  
Titratable Acidity ◽  
Physicochemical Characteristics ◽  
Soluble Solids ◽  
Content Type ◽  
Minimum Requirement ◽  
Sensory Acceptance

Purpose The purpose of this study was to evaluate beet and orange mixed juices added with lyophilized Lactobacillus acidophilus probiotic culture. Design/methodology/approach Two formulations of probiotic beet and orange mixed juices (1:1 e 1:2 v/v) were prepared, stored at 4°C for 28 days and were evaluated for probiotic survival, physicochemical stability, antioxidant activity and sensory acceptance. The probiotic culture was added in a lyophilized form and was not propagated in culture media or juice. Findings Physicochemical characteristics (pH, titratable acidity, total soluble solids and color) and antioxidant activity showed no undesirable alterations during storage. The number of probiotics followed established minimum requirement for probiotic foods (109 CFU/200mL) during the 28 days of storage. The juices showed good sensory acceptance and purchase intention, especially regarding the color of the product. Practical implications The beet and orange mixed juices are suitable carriers for L. acidophilus with a shelf life of at least 28 days at 4°C. Originality/value Direct addition of the probiotic culture could result in high probiotic survival in mixed juices, dispensing the propagation step.

scholarly journals Modelling of chlorophyll-a and Microcystis aeruginosa decay under the effect of different oxidants in culture media

Water SA ◽  
2020 ◽  
Vol 46 (3 July) ◽  
Author(s):  
Ivan Juárez ◽  
Jorge Oswaldo Aranda ◽  
Sandro Goñi ◽  
Melina Celeste Crettaz-Minaglia ◽  
Daniela Sedan ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Microcystis Aeruginosa ◽  
Exposure Time ◽  
Culture Media ◽  
Weibull Model ◽  
Distribution Model ◽  
Chl A ◽  
Freshwater Bodies ◽  
Low Exposure ◽  
Highly Correlated

Blooms of the cyanobacterium Microcystis aeruginosa are common in many eutrophic freshwater bodies and pose a serious threat to water quality, potentially giving rise to high turbidity, food web alterations, increased production of toxic microcystin (MC-LR) and odorous compounds. The comparative effectiveness of oxidant treatment of M. aeruginosa cells in culture media was evaluated by applying a mathematical model of chlorophyll-a (Chl-a), cells and MC removal. The oxidants were chlorine (1–5 mg∙L-1), hydrogen peroxide (HP: 50–150 mg∙L-1), percitric acid (PCA: 10–50 mg∙L-1), and peracetic acid (PAA: 1.5–7.5 mg∙L-1). The Weibull distribution model was applied to assess the degree of inactivation of M. aeruginosa viability under different oxidant treatments. First-order kinetics was successfully applied to the experimental data for Chl-a decay. Using the Weibull model, it was possible to predict the required exposure time (Tr) for oxidants to achieve a 99.9% reduction in viable M. aeruginosa cells with respect to the initial value. 5 mg∙L-1 chlorine produced a 81% degradation of [D-Leu1] MC-LR after 72 h, with an exposure time (Tr) of 141 h. Among the peroxide treatments (HP, PCA and PAA), PCA (10–50 mg∙L-1) produced the highest level of [D-Leu1] MC-LR degradation (39–79%), with low exposure times (Tr = 119–125 h). Chl-a concentration and M. aeruginosa counts for each oxidant treatment were highly correlated and successfully linked by a cubic polynomial. This is the first modelling report of M. aeruginosa decay by oxidant treatments.

scholarly journals Culture of equine bone marrow mononuclear fraction and adipose tissue-derived stromal vascular fraction cells in different media

2013 ◽  
Vol 33 (suppl 1) ◽  
pp. 20-24 ◽  
Author(s):  
Gesiane Ribeiro ◽  
Cristina O. Massoco ◽  
José Corrêa de Lacerda Neto
Keyword(s):  
Cell Culture ◽  
Bone Marrow ◽  
Adipose Tissue ◽  
Culture Media ◽  
Stromal Vascular Fraction ◽  
Bone Marrow Aspiration ◽  
Cell Culture Media ◽  
Colony Forming Units ◽  
Fetal Bovine ◽  
Equine Bone

The objective of this study was to evaluate the culture of equine bone marrow mononuclear fraction and adipose tissue - derived stromal vascular fraction cells in two different cell culture media. Five adult horses were submitted to bone marrow aspiration from the sternum, and then from the adipose tissue of the gluteal region near the base of the tail. Mononuclear fraction and stromal vascular fraction were isolated from the samples and cultivated in DMEM medium supplemented with 10% fetal bovine serum or in AIM-V medium. The cultures were observed once a week with an inverted microscope, to perform a qualitative analysis of the morphology of the cells as well as the general appearance of the cell culture. Colony-forming units (CFU) were counted on days 5, 15 and 25 of cell culture. During the first week of culture, differences were observed between the samples from the same source maintained in different culture media. The number of colonies was significantly higher in samples of bone marrow in relation to samples of adipose tissue.

Optimization of an effective growth medium for culturing probiotic bacteria for applications in strict vegetarian food products

2012 ◽  
Vol 2 (10) ◽  
pp. 369 ◽  
Author(s):  
Manju Pathak ◽  
Danik Martirosyan
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Growth Medium ◽  
Culture Medium ◽  
Culture Media ◽  
Plant Seed ◽  
Meat Extract ◽  
Colony Forming Units ◽  
Lactobacillus Lactis ◽  
De Man

Background: This study aimed to modify de Man Rogosa Sharpe culture medium (termed MRS) for selective cultivation of probiotics strain for the consumption by the strictly vegetarian human population. Vegetarian probiotic foods by definition must be free from all animal-derived ingredients. This not only includes the product ingredients but the probiotic inoculum as well. Probiotic starter cultures are traditionally grown and stored in media containing milk or meat-derived ingredients. The presence of these ingredients makes the probiotic cell concentrates unsuitable for use in vegetarian products and thus creates the need for a growth medium which is free from animal-derived ingredients. Present study investigated the growth of a strain of Lactobacillus lactis in MRS. The present invention relates in general to a bacterial culture media, and more specifically a complex microbial culture media, based on plant seed powder extract in place of animal extract for probiotic bacterial growth.Methods: Lactobacillus lactis, a probiotic, was grown in standard MRS culture medium as well as in our various test media (TM) containing various vegetal source in place of beef extract, yeast extract and peptone as in case of MRS. The inoculated culture mediums were incubated at 37C for 72 hours and growth of probiotic is recorded at regular intervals. The growth was recorded as Colony Forming Units (CFUs).Results: The best growth of probiotic is observed in TM 2. TM 2 is the leguminous seed extract. Starter culture mediums for probiotics or other bacteria primarily contain protein from animal source. The possibility of using vegetal protein from TM 2 extract in place of peptones and meat extract for the nitrogen supplementation of culture media for the growth of lactic acid bacteria has been demonstrated. Conclusion: The absolute vegetarian culture medium containing TM 2 is better than standard MRS for the growth of probiotics.Abbreviations: de Man Rogosa Sharpe (MRS), Colony Forming Units (CFU), test media (TM), National Dairy Research Institute (NDRI), Tamarind seed powder (TSP), solid-state fermentation (SSF), Lactobacillus casei Shirota (LcS)Keywords: probiotics, lactic acid bacteria, vegetarian

Sign in / Sign up

Export Citation Format

Share Document