Inhibition of a spoilage exopolysaccharide producer by bioprotective extracts from Lactobacillus acidophilus CRL641 and Latilactobacillus curvatus CRL705 in vacuum-packaged refrigerated meat discs.

The effect of bioprotective extracts (BEs) from Lactobacillus acidophilus CRL641 (BE-1) and Latilactobacillus curvatus CRL705 (BE-2) against the exopolysaccharide producer Latilactobacillus sakei CRL1407 in vacuum-packaged meat discs at 4 °C was evaluated. Lat. sakei CRL1407 was able to grow in control samples from 2.80 to 7.77 log CFU/g after 38 days. BE-1 and BE-2 reduced bacterial growth by 2.11 and 1.35 log CFU/g, respectively, but their combination led to a greater growth reduction (3.31 log CFU/g). The antimicrobial activity was detected in treated samples with BE-1 and BE-1 + BE-2 until day 16, while with BE-2 only at the initial time. The pH values remained constant in the discs treated with the BEs combination, whereas the greatest drop in pH was observed in control samples. The minor lipid oxidation without perceptible color changes was detected in the presence of BE-1 and BE-1 + BE-2. The combination of BEs as biocontrol agent plus conventional preservation barriers could extend the fresh meat shelf-life without quality loss.

Bioprotective extracts from Lactobacillus acidophilus CRL641 and Latilactobacillus curvatus CRL705 inhibit a spoilage exopolysaccharide producer in a refrigerated meat system.

The effect of bioprotective extracts (BEs) from Latilactobacillus curvatus CRL705 and Lactobacillus acidophilus CRL641 against Latilactobacillus sakei CRL1407 was evaluated in a refrigerated meat model system under vacuum and aerobic conditions at 4 and 10 °C. As shown by culturing, the BE-1 from L. acidophilus completely inhibited the spoilage strain, while that from Lat. Curvatus CRL705 (BE-2) and its combination with BE-1 exerted a bacteriostatic effect. The antimicrobial activity and exopolysaccharide production correlated with the efficacy of inhibitory treatment while final pH decrease was higher in control samples. When flow cytometry was applied, a lack of correlation with plate counting was found; counts under the detection limit for BE-1 at 21 and 28 days at 4 and 10 °C represented between 64.15 and 73.70% of dead cells. Thus, the concurrence of lactic acid bacteria as biocontrol agents and the use of more accurate tools to prevent the growth of deteriorating species will contribute to the extension of fresh meat shelf-life without quality loss.

Probiotic and Synbiotic Sorbets Produced with Jussara (Euterpe edulis) Pulp: Evaluation Throughout the Storage Period and Effect of the Matrix on Probiotics Exposed to Simulated Gastrointestinal Fluids.

The aims of the present study were to develop and evaluate different formulations of probiotic and synbiotic sorbets produced with jussara (Euterpe edulis) pulp, polydextrose, Lactobacillus acidophilus LA3, and Lactobacillus paracasei BGP1. The pasteurized jussara pulp presented high content of phenolic compounds, especially anthocyanins, which were not inhibitory to the probiotics used in this study. The levels of polyphenols and anthocyanins present in the sorbets were also high and kept stable for 120 days, as well as the populations of both probiotics. On the other hand, probiotic populations reduced ca. 4 log CFU/g when exposed to simulated gastrointestinal fluids. Altogether, the sorbets produced in this study showed interesting results, indicating the viability on producing functional foods with probiotics, prebiotics, and other components that are rich in polyphenols, such as jussara pulp. The combination of these elements can improve the health beneficial effects of these compounds and provide important advantages to the intestinal microbiota of consumers.

Evaluation of sample extracting methods of FCSM by Lactobacillus acidophilus based on a UPLC-Q-TOF-MS global metabolomics analysis

Abstract The study of metabolomics requires extracting as many metabolites as possible from a biological sample. This study aimed to determine the optimal method for the extraction of metabolites from solid-state fermented cottonseed meal (FCSM). The UPLC-Q-TOF-MS global metabolomics technology was used to detect the metabolites in FCSM, and the extraction quantity and extraction efficiency of seven different extraction methods, specifically the WA, 50MeOH, 50MeOHB, 50MeCNB, 80MeOHB, 80MeOH and AMF methods were evaluated. The results showed that the number of VIP metabolites extracted by AMF method are 196 and 184 in ESI+ and ESI- mode respectively, it is the largest number of all exacted methods; and the AMF methods also provided a higher extraction efficiency compared with the other methods, especially in indoleacrylic acid, dl-tryptophan and epicatechin (p < 0.01). As a result, AMF/-4 °C method was identified as the best method for the extraction of metabolites from FCSM by Lactobacillus acidophilus. Our study establishes a technical basis for future metabolomics research of fermented feed.

Evaluation of sample extracting methods of FCSM by Lactobacillus acidophilus based on a UPLC-Q-TOF-MS global metabolomics analysis.

The study of metabolomics requires extracting as many metabolites as possible from a biological sample. This study aimed to determine the optimal method for the extraction of metabolites from solid-state fermented cottonseed meal (FCSM). The UPLC-Q-TOF-MS global metabolomics technology was used to detect the metabolites in FCSM, and the extraction quantity and extraction efficiency of seven different extraction methods, specifically the WA, 50MeOH, 50MeOHB, 50MeCNB, 80MeOHB, 80MeOH and AMF methods were evaluated. The results showed that the number of VIP metabolites extracted by AMF method are 196 and 184 in ESI+ and ESI- mode respectively, it is the largest number of all exacted methods; and the AMF methods also provided a higher extraction efficiency compared with the other methods, especially in indoleacrylic acid, dl-tryptophan and epicatechin (p<0.01). As a result, AMF/-4°C method was identified as the best method for the extraction of metabolites from FCSM by Lactobacillus acidophilus. Our study establishes a technical basis for future metabolomics research of fermented feed.

Soy extract and maltodextrin as microencapsulating agents for Lactobacillus acidophilus: a model approach.

The present study aimed to optimise the microencapsulation of Lactobacillus acidophilus La-05 by spray drying, using soy extract and maltodextrin as encapsulants. Air inlet temperature, maltodextrin/soy extract ratio and feed flow rate were investigated through Central Composite Rotational Design (CCRD). Probiotic viability increased with increasing the proportion of soy extract. Temperature and feed flow rate had a negative effect. Particle diameter ranged from 4.97 to 8.82 µm, water activity from 0.25 to 0.52 and moisture from 2.30 to 7.01 g.100g-1 Particles produced following the optimised conditions (air temperature of 87 °C, maltodextrin/soy extract ratio of 2:3 w.w-1, feed flow rate of 0.54 L.h-1) reached Encapsulation yield (EY) of 83%. Thermogravimetry and FTIR analysis suggested that microcapsules could protect L. acidophilus cells against dehydration and heating. During storage, microencapsulated probiotic had high cell viability (reductions ranged between 0.12 and 1.72 log cycles). Soy extract/maltodextrin presented well-encapsulating properties of Lactobacillus acidophilus La-05.

Synbiotic aerated dessert: diet product development and evaluation of the intake effects in individuals with metabolic syndrome / Sobremesa aerada simbiótica: desenvolvimento do produto diet e avaliação dos efeitos da ingestão sobre indivíduos com síndrome metabólica

The objective of this work was to adapt a synbiotic aerated diet dessert, produced with the addition of a probiotic culture of Lactobacillus acidophilus La-5 and prebiotic ingredients (fructooligosaccharides and inulin), from the previously developed sucrose-containing formulation, and to evaluate the effects of its ingestion on adult volunteers with metabolic syndrome (MetS) during a period of 8 weeks of intervention. In addition, to improve the resistance of the probiotic to simulated gastrointestinal conditions, a microencapsulation process was optimized. For the development of the product, the formulations were produced in triplicates, in which probiotic culture survival, instrumental texture and sensory acceptability were evaluated up to 112 days of storage under freezing (-18 °C). Subsequently, a randomized, double-blind, placebo-controlled trial was carried out in which the product developed was administered to forty-five volunteers with MetS assigned into two groups, each receiving 40 g/day of: synbiotic diet mousse (SDM) (n=23) and placebo diet mousse (PDM) without pro- and prebiotics (n=22). Fasting blood samples were collected at the beginning and after 8 weeks of daily consumption of both mousses to determine the anthropometric, biochemical, haematological, inflammatory, and immunological parameters. Afterward, with the goal of improving the survival of L. acidophilus La-5 to in vitro simulated gastrointestinal conditions, the microencapsulation process conditions of the probiotic strain via spray drying were optimized using inulin as the encapsulating agent. The viability of L. acidophilus La-5 incorporated into SDM was above 7.8 log CFU/g and remained stable throughout storage. PDM showed lower acceptability (5.77-6.50) after storage than SDM (6.67-7.03). The texture was the most appreciated attribute and hardness of the SDM increased during storage, but remained stable for PDM. The clinical trial revealed significant reductions of total cholesterol and HDL-cholesterol, as well as of immunoglobulins (A and M), and interleukin-1ß in both groups during the intervention period. However, regarding intergroup changes, there were not any significant differences for all parameters evaluated (p>0.05). After the optimization of the microencapsulation process of the probiotic culture (80 mL/min, 82% and 10%, respectively for feed flow, aspiration rate, and inulin concentration), the microencapsulated probiotic strain incorporated in the SDM mousse showed the highest in vitro gastrointestinal survival (p<0.05) in the different stages of the assay, as follows: after the gastric phase: 5.68 log CFU/g (83.3%), the enteral phase I: 5.61 log CFU/g (82.3%), the enteral phase II: 5.56 log CFU/g (81.4%). Therefore, these results suggest that the presence of probiotic and prebiotics in SDM did not provide an additional effect on the health of volunteers with MetS. Additionally, the results confirm the appropriateness of the spray drying process to microencapsulate L. acidophilus La-5 using inulin as coating agent, providing increased resistance to the microencapsulated probiotic strain under in vitro gastrointestinal stress

O objetivo deste trabalho foi adaptar uma sobremesa aerada simbiótica diet do tipo musse, processada com a adição de uma cultura probiótica de Lactobacillus acidophilus La-5 e de ingredientes prebióticos (fruto-oligossacarídeos e inulina), a partir da formulação contendo sacarose desenvolvida anteriormente, e avaliar os efeitos de sua ingestão em voluntários adultos com síndrome metabólica (MetS) durante um período de 8 semanas de intervenção. Adicionalmente, para melhorar a resistência do probiótico frente às condições gastrintestinais simuladas, otimizou-se um processo de microencapsulação da cepa probiótica. Para o desenvolvimento do produto, as formulações foram produzidas em triplicata, em que se avaliou a sobrevivência da cultura probiótica, a textura instrumental e a aceitabilidade sensorial até 112 dias de armazenamento sob congelamento (-18 oC). Em seguida, foi realizado um estudo randomizado, duplo-cego e controlado por placebo, no qual o produto desenvolvido foi administrado a quarenta e cinco indivíduos com MetS divididos em dois grupos, cada um recebendo 40 g/dia de: mousse simbiótica diet (SDM) (n=23) e musse placebo diet (PDM) sem componentes pro- e prebióticos (n=22). As amostras sanguíneas foram coletadas em jejum no início e após 8 semanas de consumo diário de ambas as musses para a determinação dos parâmetros antropométricos, bioquímicos, hematológicos, inflamatórios e imunológicos. Posteriormente, com o intuito de melhorar a sobrevivência do L. acidophilus La-5 em condições gastrointestinais simuladas in vitro, as condições de processo de microencapsulação da cepa probiótica via spray drying foram otimizadas, utilizando inulina como agente encapsulante. A viabilidade de L. acidophilus La-5 incorporados na SDM foi superior a 7,8 log UFC/g e se manteve estável ao longo do armazenamento. A PDM mostrou menor aceitabilidade (5.77-6.50) após o armazenamento do que a SDM (6.67-7.03). A textura foi o atributo mais apreciado, sendo que a dureza da SDM apresentou elevação, enquanto a da PDM manteve-se estável. O ensaio clínico revelou reduções significativas de colesterol total, colesterol-HDL, imunoglobulinas (A e M) e interleucina1ß em ambos os grupos durante o período de intervenção. Entretanto, no que se refere às mudanças intergrupos, não se observou diferenças significativas para todos os parâmetros avaliados (p>0,05). Após a otimização do processo de microencapsulação da cultura probiótica (80 mL/min, 82% e 10%, respectivamente para o fluxo de alimentação, taxa de aspiração e concentração de inulina), a cepa probiótica microencapsulada incorporada a amostra SDM apresentou a maior sobrevivência gastrointestinal in vitro (p<0,05) nas diferentes etapas do ensaio, a saber: após a fase gástrica: 5,68 log UFC/g (83,3%); fase entérica I: 5,61 log UFC/g (82,3%); fase entérica II: 5,56 log UFC/g (81,4%). Portanto, esses resultados sugerem que a presença de probiótico e prebiótico na SDM não apresentou efeitos adicionais na saúde dos voluntários com MetS. Adicionalmente, os resultados confirmaram a adequação do processo de spray drying para a microencapsulação de L. acidophilus La-5 utilizando inulina como agente de revestimento, proporcionando uma maior resistência da cepa probiótica microencapsulada às condições gastrintestinais simuladas in vitro.

Desenvolvimento e caracterização de iogurte adicionado de geleiada da casca de jabuticaba e de cultura probiótica

O objetivo deste trabalho foi desenvolver e caracterizar iogurte adicionado de geleiada de casca de jabuticaba e de Lactobacilos acidophilus LA-3 e analisar suas características microbiológicas e fisico-químicas. Inicialmente, preparou-se geleiada com o resíduo do processamento de jabuticaba. Em seguida, o iogurte foi processado, adicionado de 5% de geleiada e dividido em dois tratamentos: iogurte adicionado de L. acidophilus LA-3 e controle, sem adição da cultura. Realizou-se análises de pH, acidez titulável, sólidos solúveis, coliformes a 30°C e a 45°C e de fungos filamentosos e leveduras nas amostras de geleiada. As amostras de iogurte foram submetidas às análises de pH, acidez titulável, extrato seco total, umidade, gordura, cinzas, proteína, além da contagem de bactérias láticas, fungos filamentosos e leveduras e coliformes a 30°C e a 45°C. Verificou-se resultados médios de 2,38 para pH, 1,166 para acidez (% ácido cítrico) e 67,33 °Brix para sólidos solúveis nas amostras de geleiadas. Por outro lado, as amostras de iogurte do tratamento controle diferenciaram daquelas adicionadas de cultura probiótica (p < 0,05) em relação a pH, acidez, extrato seco e umidade. Os teores de cinzas e gordura não diferiram (p > 0,05) entre os tratamentos ao longo do tempo. Constatou-se <3,0 NMP/g de coliformes a 30°C e a 45°C em ambos os tratamentos e <1,0x10¹ UFC/g estimado para fungos filamentosos e leveduras para geleiada e para iogurte. As contagens de L. acidophilus LA-3 e de L. bulgaricus no iogurte foram acima de 108 UFC/g logo após a produção, enquanto após 30 dias a 5°C observou-se contagens acima de 107 UFC/g. Streptococus thermophilus manteve-se acima 109 UFC/g durante a estocagem. Portanto, o iogurte contendo geleiada de casca de jabuticaba pode ser utilizado como substrato potencial para L. acidophilus LA-3 e [...](AU)

The objective of this study was to develop and characterize yogurt added of jelly of jabuticaba peel and of Lactobacillus acidophilus LA-3, and determine its microbiological and physical-chemical characteristics. Initially, there was prepared jelly with processing waste jabuticaba. Then, the processed yogurt was added of 5% jabuticaba peel jelly and divided into two treatments: L. acidophilus yogurt added, and control without addition of this culture. The analyses of pH, acidity (% citric acid), soluble solids, coliforms at 30°C and 45°C, and molds and yeasts were made to the jelly samples. For yoghurt, pH, titratable acidity (% lactic acid and citric acid), total soluble solids, moisture, fat, protein and ash, as well as count of lactic acid bacteria, molds and yeasts, and coliforms at 30°C and 45°C were determined. For jelly, it was found average results of pH equaI 2.38, 1.166 to acidity (% citric acid) and 67.33 °Brix to soluble solids. On the other hand the yogurt samples of control treatment differed from those added of probiotic culture (p < 0.05) in relation to pH, acidity, solids and moisture. For analyzes of ash and fat it was not found significant difference between treatments over time. lt was observed <3. O MPN/g of coliforms at 30°C and 45°C in both treatments and <1.0 x 10¹ CFU/g estimated of molds and yeasts in jelly and yogurt samples. L. acidophilus LA-3 and starter cultures of Lactobacillus bulgaricus were above 108 CFU/g after yogurt production, while after 30 days at 5°C it was observed counts above 107 CFU/g. Streptococcus thermophilus remained above 109 CFU/g during storage. Therefore, yogurt containing the jelly may be used as a potential substrate for L. acidophilus LA-3 and […] (AU)

Adsorção “in vitro” de Ochratoxina A por probióticos utilizados na aquicultura / In vitro adsorption of ochratoxin A by probiotics used in aquaculture

Devido as constantes contaminações de rações comerciais pelas micotoxinas, o presente trabalhoteve por objetivo avaliar in vitro a capacidade de dois produtos comerciais utilizados na aquicultura emadsorverem Ochratoxina A (OTA). Dois tipos de probióticos comerciais, compostos por Bacillus subtilis,Bifidobacterium bifidum, Enterococcus faecium e Lactobacillus acidophilus (Probiótico A) e, Saccharomycescerevisiae provenientes de cervejaria (Probiótico B) foram utilizados no ensaio. Soluções em tampão fosfatosalino (PBS), com pH de 1,5 e 7,5, foram elaborados para simular o pH do estômago e intestino de tilápias doNilo (Oreochromis niloticus). As soluções de PBS foram testadas nas duas faixas de pH (1,5 e 7,5), com asconcentrações dos produtos comerciais de 0%; 25%; 50%; 75% e 100%, para uma concentração de 1.000 ng.mL-1de OTA. As concentrações de OTA foram adicionadas em microtubos para que fosse determinado a capacidadede adsorção dos probióticos utilizados neste estudo. Na detecção e quantificação de OTA, utilizou-se ametodologia de Cromatografia Líquida de Alta Eficiência (CLAE). Os resultados finais mostraram que osprobióticos A e B nas suas concentrações máximas foram capazes de adsorver OTA nas quantidades de 13,78 a76,81 e 301,48 a 317,54 (ng.mL-1), respectivamente. Os dados mostraram que os dois tipos de probióticos sãopromissores para adsorverem OTA nas condições simuladas de pH gastrointestinal de tilápias do Nilo, sendo amaior eficiência verificada para o probiótico B(AU)

Given the constant contamination of animals by feed mycotoxins, this study aimed to evaluate invitro the ability of commercial products used in aquaculture as adsorbents of ochratoxin A (OTA). Twocomercial probiotics, composed of Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium andLactobacillus acidophilus (Probiotic A) and one made of dry yeast of Saccharomyces cerevisiae from a brewery(Probiotic B) were used in the assay. Phosphate buffered saline solutions (PBS) at pH 1.5 and 7.5 wereformulated to simulate the pH of the stomach and intestine of Nile Tilapia (Oreochromis niloticus). The PBSsolutions were tested at the two pH (1,5 and 7,5) with the probiotics concentrations of 0%; 25%; 50%; 75% and100% for a OTA concentration of 1.000 ng.mL-1. The OTA concentrations were added in microtubes forevaluation of adsorption capacity of the probiotics. The OTA detection and quantification were performed byHigh Performance Liquid Chromatography (HPLC). The final results showed that the probiotics A and B in theirmaximum concentration were capable of adsorbing OTA in amounts from 13.78 to 76.81 and from 301.48 to317.54 (ng.mL-1), respectively. The data showed that this two probiotics were very promissimg at adsorbingOTA under simulated gastrointestinal conditions of pH of tilapias, being more efficient the probiotic B(AU)

Adsorção “in vitro” de Ochratoxina A por probióticos utilizados na aquicultura / In vitro adsorption of ochratoxin A by probiotics used in aquaculture

Devido as constantes contaminações de rações comerciais pelas micotoxinas, o presente trabalhoteve por objetivo avaliar in vitro a capacidade de dois produtos comerciais utilizados na aquicultura emadsorverem Ochratoxina A (OTA). Dois tipos de probióticos comerciais, compostos por Bacillus subtilis,Bifidobacterium bifidum, Enterococcus faecium e Lactobacillus acidophilus (Probiótico A) e, Saccharomycescerevisiae provenientes de cervejaria (Probiótico B) foram utilizados no ensaio. Soluções em tampão fosfatosalino (PBS), com pH de 1,5 e 7,5, foram elaborados para simular o pH do estômago e intestino de tilápias doNilo (Oreochromis niloticus). As soluções de PBS foram testadas nas duas faixas de pH (1,5 e 7,5), com asconcentrações dos produtos comerciais de 0%; 25%; 50%; 75% e 100%, para uma concentração de 1.000 ng.mL-1de OTA. As concentrações de OTA foram adicionadas em microtubos para que fosse determinado a capacidadede adsorção dos probióticos utilizados neste estudo. Na detecção e quantificação de OTA, utilizou-se ametodologia de Cromatografia Líquida de Alta Eficiência (CLAE). Os resultados finais mostraram que osprobióticos A e B nas suas concentrações máximas foram capazes de adsorver OTA nas quantidades de 13,78 a76,81 e 301,48 a 317,54 (ng.mL-1), respectivamente. Os dados mostraram que os dois tipos de probióticos sãopromissores para adsorverem OTA nas condições simuladas de pH gastrointestinal de tilápias do Nilo, sendo amaior eficiência verificada para o probiótico B

Given the constant contamination of animals by feed mycotoxins, this study aimed to evaluate invitro the ability of commercial products used in aquaculture as adsorbents of ochratoxin A (OTA). Twocomercial probiotics, composed of Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium andLactobacillus acidophilus (Probiotic A) and one made of dry yeast of Saccharomyces cerevisiae from a brewery(Probiotic B) were used in the assay. Phosphate buffered saline solutions (PBS) at pH 1.5 and 7.5 wereformulated to simulate the pH of the stomach and intestine of Nile Tilapia (Oreochromis niloticus). The PBSsolutions were tested at the two pH (1,5 and 7,5) with the probiotics concentrations of 0%; 25%; 50%; 75% and100% for a OTA concentration of 1.000 ng.mL-1. The OTA concentrations were added in microtubes forevaluation of adsorption capacity of the probiotics. The OTA detection and quantification were performed byHigh Performance Liquid Chromatography (HPLC). The final results showed that the probiotics A and B in theirmaximum concentration were capable of adsorbing OTA in amounts from 13.78 to 76.81 and from 301.48 to317.54 (ng.mL-1), respectively. The data showed that this two probiotics were very promissimg at adsorbingOTA under simulated gastrointestinal conditions of pH of tilapias, being more efficient the probiotic B

Safety and protective effectiveness of two strains of Lactobacillus with probiotic features in an experimental model of salmonellosis.

Two strains of Lactobacillus, previously isolated from bovine faeces and tested in vitro for properties desired in probiotics, were evaluated for their in vivo effectiveness in protecting against experimental salmonellosis. L. salivarius L38 and L. acidophilus L36 previously demonstrated the ability to successfully colonize the gastrointestinal tract of germ-free mice and stimulate the immune system associated with the intestinal mucosa. L38- or L36-feeding showed no detrimental effect on the general health indicators and did not induce changes in normal architecture of liver and small intestine, indicating that the use of these strains is apparently safe. In control animals fed L38 strain, several cytokines had augmented mRNA levels that can be associated with a homeostatic state of intestinal mucosa, while L36 had less diverse regulation. IgA production and secretion in the intestinal lumen induced by infection was abrogated by pretreating with both lactobacilli. In addition, liver and small intestine histological scores and, translocation of Salmonella cells to liver and spleen, indicated that these strains did not confer protection against the infection. So, the IL-12:IL-18àIFN-g axis, essential for an effective immune response against Salmonella, was not favored with L38 or L36 strains. However, increased expression of IL-10 in different portions of the gastrointestinal tract of L38-fed animals is indicative of anti-inflammatory effect to be explored furthermore.

Avaliação de probiótico na alimentação de poedeiras comerciais no segundo ciclo de postura / Evaluation of probiotics in feed for laying hens in the second cycle stance

Avaliou-se o efeito da inclusão de probiótico sobre o desempenho e a qualidade dos ovos de poedeiras semipesadas no segundo ciclo de postura. Foram utilizadas 450 aves com 69 semanas de idade, distribuídas aleatoriamente em um delineamento inteiramente ao acaso, em cinco tratamentos, seis repetições e 15 aves por unidade experimental. A ração experimental foi à base de milho e farelo de soja e suplementada com probiótico composto por Lactobacillus acidophilus, Streptococcus faecium e Bifidobacterium bifidum. O experimento teve a duração de 16 semanas e foi dividido em quatro períodos de 28 dias cada, nos quais as aves receberam cinco rações experimentais contendo diferentes porcentagens de inclusão de probiótico, 0; 0,05; 0,10; 0,15 e 0,20%. Não foi observado efeito (P>0,05) da inclusão de probiótico sobre o desempenho e a qualidade dos ovos de galinhas poedeiras no segundo ciclo de postura. A inclusão de 0,10% de probiótico influenciou negativamente a gravidade específica dos ovos. A utilização de probiótico para galinhas no segundo ciclo de postura não interfere na produção e na qualidade dos ovos.

Evaluating the effect of the inclusion of probiotic on the performance and egg quality of laying hens in the second laying cycle, 450 birds were used at 69 weeks of age, distributed in a completely randomized design, in five treatments, six replicates and 15 poultries per experimental unit. The experimental diets were based on corn and soybean meal and supplemented with increasing levels of probiotic consisting of Lactobacillus acidophilus, Streptococcus faecium, and Bifidobacterium bifidum. The experiment lasted 16 weeks, divided into four periods of 28 days each, in which the birds were fed five experimental diets containing different percentages of probiotic inclusion, 0; 0.05; 0.10; 0.15 and 0.20%, in the period from 69 to 85 weeks of age. There was no effect (P> 0.05) of the inclusion of probiotic on performance and egg quality of laying hens in the second laying cycle. The inclusion of 0.10% of probiotic negatively influenced the specific gravity of eggs. The probiotic used for laying hens in the second cycle does not interfere in production and egg quality.

Metabolism of biodiesel-derived glycerol in probiotic Lactobacillus strains.

Three probiotic Lactobacillus strains, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus delbrueckii, were tested for their ability to assimilate and metabolize glycerol. Biodiesel-derived glycerol was used as the main carbon and energy source in batch microaerobic growth. Here, we show that the tested strains were able to assimilate glycerol, consuming between 38 and 48 % in approximately 24 h. L. acidophilus and L. delbrueckii showed a similar growth, higher than L. plantarum. The highest biomass reached was 2.11 g L⁻¹ for L. acidophilus, with a cell mass yield (Y (X/S)) of 0.37 g g⁻¹. L. delbrueckii and L. plantarum reached a biomass of 2.06 and 1.36 g L⁻¹. All strains catabolize glycerol mainly through glycerol kinase (EC 2.7.1.30). For these lactobacillus species, kinetic parameters for glycerol kinase showed Michaelis-Menten constant (K(m)) ranging from 1.2 to 3.8 mM. The specific activities for glycerol kinase in these strains were in the range of 0.18 to 0.58 U mg protein⁻¹, with L. acidophilus ATCC 4356 showing the maximum specific activity after 24 h of cultivation. Glycerol dehydrogenase activity was also detected in all strains studied but only for the reduction of glyceraldehyde with NADPH (K(m) for DL-glyceraldehyde ranging from 12.8 to 32.3 mM). This enzyme shows a very low oxidative activity with glycerol and NADP+ and, most likely, under physiological conditions, the oxidative reaction does not occur, supporting the assumption that the main metabolic flux concerning glycerol metabolism is through the glycerol kinase pathway.

Avaliação de probiótico na alimentação de poedeiras comerciais no segundo ciclo de postura / Evaluation of probiotics in feed for laying hens in the second cycle stance

Avaliou-se o efeito da inclusão de probiótico sobre o desempenho e a qualidade dos ovos de poedeiras semipesadas no segundo ciclo de postura. Foram utilizadas 450 aves com 69 semanas de idade, distribuídas aleatoriamente em um delineamento inteiramente ao acaso, em cinco tratamentos, seis repetições e 15 aves por unidade experimental. A ração experimental foi à base de milho e farelo de soja e suplementada com probiótico composto por Lactobacillus acidophilus, Streptococcus faecium e Bifidobacterium bifidum. O experimento teve a duração de 16 semanas e foi dividido em quatro períodos de 28 dias cada, nos quais as aves receberam cinco rações experimentais contendo diferentes porcentagens de inclusão de probiótico, 0; 0,05; 0,10; 0,15 e 0,20%. Não foi observado efeito (P>0,05) da inclusão de probiótico sobre o desempenho e a qualidade dos ovos de galinhas poedeiras no segundo ciclo de postura. A inclusão de 0,10% de probiótico influenciou negativamente a gravidade específica dos ovos. A utilização de probiótico para galinhas no segundo ciclo de postura não interfere na produção e na qualidade dos ovos.(AU)

Evaluating the effect of the inclusion of probiotic on the performance and egg quality of laying hens in the second laying cycle, 450 birds were used at 69 weeks of age, distributed in a completely randomized design, in five treatments, six replicates and 15 poultries per experimental unit. The experimental diets were based on corn and soybean meal and supplemented with increasing levels of probiotic consisting of Lactobacillus acidophilus, Streptococcus faecium, and Bifidobacterium bifidum. The experiment lasted 16 weeks, divided into four periods of 28 days each, in which the birds were fed five experimental diets containing different percentages of probiotic inclusion, 0; 0.05; 0.10; 0.15 and 0.20%, in the period from 69 to 85 weeks of age. There was no effect (P> 0.05) of the inclusion of probiotic on performance and egg quality of laying hens in the second laying cycle. The inclusion of 0.10% of probiotic negatively influenced the specific gravity of eggs. The probiotic used for laying hens in the second cycle does not interfere in production and egg quality.(AU)

Comportamento de cepas distintas de Lactobacillus acidophilus em queijo petit-suisse

O objetivo do presente trabalho foi avaliar as características de físico-químicas e microbiológicas de queijo petit-suisse processado com a adição de duas cepas de Lactobacillus acidophilus: LA-14 (potencialmente probiótica) e La-5 (comprovadamente probiótica), utilizando Streptococcus thermophilus TA040 como cultura starter. Três queijos petit-suisse foram preparados: Q1 (controle:TA040), Q2 (TA040 + LA-14) e Q3 (TA040 +La-5). Foram realizadas análises microbiológicas (determinação das populações dos microrganismos La-5, La-14 e TA040) e físico-químicas (umidade e pH) após 1, 7, 14, 21 e 28 dias de armazenamento dos produtos a 4±1°C. As populações de L. acidophilus oscilaram entre 7,46 e 7,62 log UFC g -1 para La-5 e entre 6,39 e 6,83 log UFC g -1 para LA-14, evidenciando que a sobrevivência de L. acidophilus no produto depende de características particulares da cepa. Populações superiores da cultura starter foram observadas para Q2 (9,58 - 9,68 log UFC g -1 ) e Q3 (9,42 - 9,79 log UFC g -1 ), quando comparadas a Q1 (9,11 - 9,23 log UFC g -1 ), sugerindo sinergismo entre L. acidophilus e o starter. A umidade e o pH permaneceram estáveis e não diferiram entre os queijos após o 1º dia de armazenamento (p>0,05). As características peculiares das cepas de L. acidophilus determinaram os comportamentos distintos observados nos queijos petitsuisse, sendo possível detectar a melhor adaptação da cepa La-5 ao produto, o que resultou em populações significativamente superiores quando comparada a LA-14.

Particular behavior of different Lactobacillus acidophilus strains in petit-suisse cheese. The objective of this study was to evaluate the physico-chemical andmicrobiological characteristics of petit-suisse cheeses manufactured with the addition of two Lactobacillus acidophilus strains: LA-14 (potentially probiotic) and La-5 (probiotic culture), using Streptococcus thermophilus TA040 as starter culture. Three cheese-making trials were prepared: Q1 (control: with TA040), Q2 (with TA040 + LA-14), and Q3 (with TA040 + La-5). Parameters analyzed included microbial counts of probiotic, potentially probiotic and starter microorganisms, and physico-chemical parameters (pH and moisture) after 1, 7, 14, 21, and 28 days of storage of the product at 4±1°C. Viable counts of L. acidophilus remained between 7.46 and 7.62 log CFU g -1 for La-5, and between 6.39 and 6.83 log CFU g -1 for LA-14. As for the starter, higher populations were observed for Q2 (9.58 - 9.68 log CFU g -1 ) and Q3 (9.42 - 9.79 log CFU g -1 ), when compared to Q1, which suggests synergism between L. acidophilus and the starter culture. Moisture and pH values remained stable for cheeses Q1, Q2, and Q3, and no significant differences were detected between cheeses after the first day of storage (p>0.05). Particular features of both L. acidophilus strains determined different behavior in petit-suisse cheese, and the better adaptation of the La-5 to the product environment was perceptible, since higher populations were observed when compared to LA-14.

[Particular behavior of different Lactobacillus acidophilus strains in petit-suisse cheese]. / Comportamento de cepas distintas de Lactobacillus acidophilus em queijo petit-suisse.

The objective of this study was to evaluate the physico-chemical and microbiological characteristics of petit-suisse cheeses manufactured with the addition of two Lactobacillus acidophilus strains: LA-14 (potentially probiotic) and La-5 (probiotic culture), using Streptococcus thermophilus TA040 as starter culture. Three cheese-making trials were prepared: Q1 (control: with TA040), Q2 (with TA040 + LA-14), and Q3 (with TA040 + La-5). Parameters analyzed included microbial counts of probiotic, potentially probiotic and starter microorganisms, and physico-chemical parameters (pH and moisture) after 1, 7, 14, 21, and 28 days of storage of the product at 4 +/- 1 degree C. Viable counts of L. acidophilus remained between 7.46 and 7.62 log CFU g(-1) for La-5, and between 6.39 and 6.83 log CFU g(-1) for LA-14. As for the starter, higher populations were observed for Q2 (9.58-9.68 log CFU g(-1)) and Q3 (9.42-9.79 log CFU g(-1)), when compared to Q1, which suggests synergism between L. acidophilus and the starter culture. Moisture and pH values remained stable for cheeses Q1, Q2, and Q3, and no significant differences were detected between cheeses after the first day of storage (p > 0.05). Particular features of both L. acidophilus strains determined different behavior in petit-suisse cheese, and the better adaptation of the La-5 to the product environment was perceptible, since higher populations were observed when compared to LA-14.

Effect of exopolysaccharides on the hydrolysis of beta-lactoglobulin by Lactobacillus acidophilus CRL 636 in an in vitro gastric/pancreatic system.

An analysis of the peptides generated by hydrolysis of BLG by nonproliferating cells of the strain Lactobacillus acidophilus CRL 636 was carried out. The effect of polysaccharides (pectin, and two EPS synthesized by two Streptococcus thermophilus strains, EPS1190 and EPS804) on BLG digestibility using an in vitro gastric/pancreatic system was analyzed. Polysaccharides are commonly used in the dairy industry to improve food texture; these hydrocolloids may interact with proteins, affecting their digestibility. Nonproliferating cells of Lb. acidophilus CRL 636 were able to hydrolyze 52% of BLG. Twenty-six resulting peptides with molecular masses in the range 544-4119 Da were identified by LC-MS/MS. These peptides resulted mostly from the hydrolysis of the more accessible N-terminal part of BLG. Degradation of BLG by pepsin was poor (8%). When BLG was previously hydrolyzed by Lb. acidophilus CRL 636, peptic hydrolysis was of 54.8%, while when pectin and EPS1190 were added, hydrolysis was higher (58.2 and 57.2%, respectively). Peptides crossing 8 kDa dialysis membranes after trypsin/chymotrypsin hydrolysis were analyzed by HPSEC. The produced peptides were smaller when BLG was hydrolyzed previously by the Lb. acidophilus strain. Moreover, in the presence of pectin, the amount of the larger peptide (3.5 kDa) observed in the size exclusion chromatograms was considerably decreased. Our studies showed that prehydrolysis of BLG by Lb. acidophilus CRL 636 had a positive influence on BLG digestibility and that polysaccharides may change the peptide profile yielded by trypsin/chymotrypsin hydrolysis, releasing smaller size peptides, which are known to be less immune-reactive. Moreover, Lb. acidophilus CRL 636 was able to hydrolyze the main epitopes (41-60, 102-124, and 149-162) of BLG, reducing its allergenic content.

Chromosomal-gene-mediated inhibition of intestinal and foodborne pathogens by Lactobacillus acidophilus AA11.

Approximately 63 strains of Lactobacillus acidophilus were isolated from Egyptian home-made cheese and examined for production of antagonism. Only eight strains demonstrated inhibitory activity against spoilage microorganisms (i.e. Staphylococcus aureus and Bacillus cereus) and pathogens (i.e. E. coli, Salmonella sp. and Shigella sp.). Lactobacillus acidophilus AA11 produced a more antimicrobial activity with a wide range of inhibition. The agent AA11 was sensitive to proteolytic enzymes and retained full activity after 30 min at 100 degrees C. Activity against sensitive cells was bactericidal but not bacteriolytic. The compound was produced during growth phase and can be extracted from the culture supernatant fluids with n-Butanol. 12 % SDS-PAGE analysis of 40% ammonium sulphate precipitated agent showed two peptides with molecular weights of approximately 36 kDa and approximately 29 kDa. No plasmid was identified in Lactobacillus acidophilus AA11 indicating that the genes encoding the inhibitory agent located on the chromosome. These characteristics identify the inhibitory substance as a bacteriocin, designated acidocin AA11 and confer the agent an application potential as a biopreservative.

Effect of lipid composition on the stability of cellular membranes during freeze-thawing of Lactobacillus acidophilus grown at different temperatures.

Lactobacillus acidophilus CRL 640 grown at the optimal temperature of 37 degrees C (M37) appeared more sensitive to freeze-thawing than when it was grown at 25 degrees C (M25). In the first case, 87% of the cells died, in contrast to 33% for cells grown at 25 degrees C. All the surviving M37 cells showed sensitivity to NaCl. However, among the surviving M25 cells, only 85% were sensitive to NaCl. The rest of the cells were considered uninjured. Freeze-thawing in cells grown at 25 degrees C showed a liberation of nucleic acids and proteins. However, the leakage was higher in M37 cells after freeze-thawing. The greater fraction of damaged cells were observed in M25 culture after freeze-thawing. A relative increase of 81% in cardiolipid (CL), with respect to total phospholipids and 72% triglycosyldiglyceride (TGDG) with respect to the total glycolipids was observed in M37. In addition, a decrease of palmitoyl (C16:0), oleoyl (C18:0) fatty acids at CL, phosphatidylglycerol (PG), and diglicosyldiglyceride (DGDG) fractions and the increase of C19 cyc and C18:0, 10-OH fatty acids in neutral lipid, and CL fractions was also apparent. In M25 cells, the concentration of DGDG and PG was higher than in M37 cells. The difference in cryotolerance between the frozen cultures emphasizes the importance of selecting appropriate conditions of growth of microorganisms for use as dietary adjuncts.

A low-pH-inducible, stationary-phase acid tolerance response in Lactobacillus acidophilus CRL 639.

Acidity is an important environmental condition encountered by lactobacilli during food fermentation. In this report we show that triggering the stationary-phase acid tolerance response (ATR) in L. acidophilus CRL 639 depends on the final growth pH. In free-pH fermentation runs (final pH = 4.5), the cells were completely resistant to acid stress, whereas cells from cultures under controlled pH (pH = 6.0) were very sensitive. The relationship between the final pH and the development of cross-resistance to different kinds of environmental stress was also evaluated. The study of protein profiles showed the overexpression of 16 proteins from 6.5 to 70.9 kDa in stationary phase cells. Seven of these proteins (26.3, 41.4, 48.7, 49.3, 54.5, 56.1, and 70.9 kDa) were expressed as result of the stationary phase itself, while nine proteins (14.1, 18.6, 21.5, 26.9, 29.3, 41.9, 42.6, 49.6, and 56.2 kDa) were exclusively induced as a result of the drop in culture pH during free fermentation runs. These results strongly suggest the involvement of these proteins in cell adaptation to environmental changes.