RESUMO
Probiotic-containing foods are among the most appreciated functional foods; however, probiotic-based dairy products cannot be consumed by people who are lactose intolerant, allergic to milk, or vegetarian or vegan individuals. Thus, new non-dairy matrices have been tested for probiotics delivery. This study evaluated the growth and viability of Limosilactobacillus fermentum ATCC 23271 and Lacticaseibacillus rhamnosus ATCC 9595 in Pitanga juice (Eugenia uniflora L.). The effects of the fermentation on the antioxidant and anti-infective properties of the juice were also analyzed. The E. uniflora juice allowed lactobacilli growth without supplementation, reaching rates around 8.4 Log CFU/mL and producing organic acids (pH values < 4) after 72 h of fermentation. The strain remained viable after 35 days of refrigerated storage. Fermentation by these bacteria increases the antioxidant capacity of the juice. The central composite rotational design was employed to evaluate the effects of bacterial inoculum and pulp concentration on growth and organic acids production by L. fermentum ATCC 23271. The strain was viable and produced organic acids in all tested combinations. L. fermentum-fermented juice and its cell-free supernatant significantly increased the survival of Tenebrio molitor larvae infected by enteroaggregative Escherichia coli 042. The results obtained in this study provide more insights into the potential of Pitanga juice to develop a functional non-dairy probiotic beverage with antioxidant and anti-infective properties.
Assuntos
Antioxidantes , Eugenia , Fermentação , Limosilactobacillus fermentum , Probióticos , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Limosilactobacillus fermentum/metabolismo , Limosilactobacillus fermentum/crescimento & desenvolvimento , Limosilactobacillus fermentum/fisiologia , Limosilactobacillus fermentum/efeitos dos fármacos , Probióticos/farmacologia , Eugenia/química , Anti-Infecciosos/farmacologia , Sucos de Frutas e Vegetais/microbiologia , Sucos de Frutas e Vegetais/análise , Lacticaseibacillus rhamnosus/metabolismo , Lacticaseibacillus rhamnosus/crescimento & desenvolvimento , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacosRESUMO
AIM: This study investigated the in vitro mechanism of action of a commercial citrus EO, Brazilian orange terpenes (BOT), on an enterotoxigenic Escherichia coli (ETEC) isolated from pig gut and on Lactobacillus rhamnosus. METHODS AND RESULTS: Firstly, bacteria were exposed sequentially to BOT every 3 h (three times) at sub-minimal inhibitory concentrations and results showed that sequential exposure to BOT provoked a higher reduction of bacteria viability than a single exposure and the reduction of ETEC viability was higher compared to that of L. rhamnosus. Then, evaluation of the BOT effects on the cell membrane permeability and integrity, indicated that BOT increased the membrane permeability and caused disruptive effects on the integrity of bacterial cells as reflected by an increase of the relative electric conductivity and the release of essential cell constituents. Interestingly, BOT effects were more pronounced on the ETEC than on L. rhamnosus. This was ratified by scanning electron microscopy, which showed more noticeable morphological damages and disturbances on ETEC cells than on the L. rhamnosus cells. Limonene was detected as the major compound in BOT by polar/nonpolar GC-MS (78·65%/79·38%). CONCLUSIONS: Results revealed that the probable mechanism of the selective antibacterial action of the citrus EO, BOT, can be described as altering more remarkable the permeability and integrity of the cytoplasmic membrane as well as the external structure of ETEC cells than L. rhamnosus cells. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides information about the mechanism of antibacterial action displayed by a citrus EO, a by-product of the citrus processing industry, as a natural alternative to antibiotics used in pig production sector to combat pathogens such as ETECs.
Assuntos
Antibacterianos/farmacologia , Citrus/química , Escherichia coli Enterotoxigênica/efeitos dos fármacos , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Óleos Voláteis/farmacologia , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Escherichia coli Enterotoxigênica/isolamento & purificação , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Especificidade da Espécie , Suínos , Terpenos/farmacologiaRESUMO
This study aimed to evaluate the influence of passion fruit by-product (PFBP) and fructooligosaccharides (FOS) on the viability of Streptococcus thermophilus TH-4 and Lactobacillus rhamnosus LGG in folate bio-enriched fermented soy products and their effect on probiotic survival and folate bio-accessibility under in vitro simulated gastrointestinal conditions during storage of the products at 4⯰C for up to 28â¯days (at days 1, 14, and 28). Kinetic parameters and folate contents before and after fermentation were also evaluated. Four different bio-enriched soy products in which the two microorganisms were used in co-cultures were studied and PFBP and/or FOS were added at 1â¯g/100â¯g, except for the control product. No differences (pâ¯<â¯0.05) between the fermented soy products (FSP) were observed for the maximum acidification rate (Vmax) and the time to reach the Vmax (Tmax) or pHâ¯5.5 (Tf), indicating that the use of PFBP and/or FOS did not affect the fermentation kinetic parameters. Only Lb. rhamnosus LGG retained the desired viability (>8â¯logâ¯CFU/mL) during storage, whereas St. thermophilus TH-4 populations decreased by day 14 reaching counts between 6.4 and 5.5â¯logâ¯CFU/mL by day 28. The folate content of all FSP increased after fermentation and the simultaneous presence of PFBP and FOS stimulated the co-culture to increase folate production. Folate content in all FSP decreased during storage. Lb. rhamnosus LGG was recovered at the end of the simulated digestion, but PFBP and/or FOS did not affect recovery. The folate content increased during the gastrointestinal assay for all FSP, especially for FSP without supplementation, suggesting an in vitro increase of folate bio-accessibility. Therefore, the bio-enriched probiotic FSP presented a great potential as an innovative functional food by delivering probiotic microorganisms and providing 14% of the recommended daily folate intake. The folate content of the FSP might be increased during gastrointestinal stress conditions, which could contribute to increase the folate bio-accessibility in the gut.
Assuntos
Ácido Fólico/farmacocinética , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Oligossacarídeos/farmacologia , Passiflora/química , Probióticos , Streptococcus thermophilus/efeitos dos fármacos , Fermentação , Microbiologia de Alimentos , Trato Gastrointestinal , Concentração de Íons de Hidrogênio , Glycine max/microbiologiaRESUMO
Essential oils (EOs), as substitutes for antibiotics in animal diets, should have selective antibacterial activity between pathogenic and beneficial bacteria from the animal gut. Thus, this study evaluated the selective antibacterial activity of Eucalyptus globulus (EG) and Pimenta pseudocaryophyllus (PP) EOs on Enterococcus faecalis as a surrogate model of pathogenic bacterium and on Lactobacillus rhamnosus as a beneficial bacterium model. The EOs antibacterial activity was evaluated by determination of minimal inhibitory concentrations (MICs), minimal bactericidal concentration (MBCs), and fractional inhibitory concentration (FIC) indices. The time-kill and sequential exposure assays were also performed, but using only the EG oil, which was the best selective EO, since it had a MIC lower on E. faecalis (7.4 mg/mL) than on L. rhamnosus (14.8 mg/mL). FIC index values showed that the combination of the two EOs had an indifferent effect (1.25 and 2.03) on E. faecalis and an additive effect (1.00) on L. rhamnosus. The time-kill assay showed that EG oil was able to kill E. faecalis within 15 min of treatment (â¼5 log reduction) and caused a reduction â¼3 log of L. rhamnosus viability. The sequential exposure assay showed that EG oil (at MIC/2) produced higher reduction on E. faecalis viability (â¼3 log) than on L. rhamnosus (â¼2 log) as well. Therefore, L. rhamnosus presented higher tolerance to the antibacterial activity of EG oil than E. faecalis did.
Assuntos
Antibacterianos/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Óleo de Eucalipto/farmacologia , Eucalyptus/química , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Óleos Voláteis/farmacologia , Pimenta/química , Animais , Antibacterianos/isolamento & purificação , Bactérias/efeitos dos fármacos , Combinação de Medicamentos , Óleo de Eucalipto/isolamento & purificação , Testes de Sensibilidade Microbiana , Óleos Voláteis/isolamento & purificaçãoRESUMO
In this work, the thermotolerance of Lactobacillus rhamnosus CRL1505, an immunobiotic strain, was studied as a way to improve the tolerance of the strain to industrial processes involving heat stress. The strain displayed a high intrinsic thermotolerance (55°C, 20 min); however, after 5 min at 60°C in phosphate buffer a two log units decrease in cell viability was observed. Different heat shock media were tested to improve the cell survival. Best results were obtained in the mediumcontaining inorganic salts (KH2PO4, Na2HPO4, MnSO4, and MgSO4) likely as using 10% skim milk. Flow cytometry analysis evinced 25.0% live cells and a large number of injured cells (59.7%) in the inorganic salts medium after heat stress. The morphological changes caused by temperature were visualized by transmission electronic microscopy (TEM). In addition, TEM observations revealed the presence of polyphosphate (polyP) granules in the cells under no-stress conditions. A DAPI-based fluorescence technique, adjusted to Gram-positive bacteria for the first time, was used to determine intracellular polyP levels. Results obtained suggest that the high initial polyP content in L. rhamnosus CRL 1505 together with the presence of inorganic salts in the heat shock medium improve the tolerance of the cells to heat shock. To our knowledge, this is the first report giving evidence of the relationship between polyP and inorganic salts in thermotolerance of lactic acid bacteria.
Assuntos
Corpos de Inclusão/metabolismo , Espaço Intracelular/metabolismo , Lacticaseibacillus rhamnosus/imunologia , Lacticaseibacillus rhamnosus/fisiologia , Polifosfatos/metabolismo , Probióticos/metabolismo , Sais/farmacologia , Termotolerância/efeitos dos fármacos , Meios de Cultura/farmacologia , Citometria de Fluxo , Fluorescência , Resposta ao Choque Térmico/efeitos dos fármacos , Corpos de Inclusão/efeitos dos fármacos , Corpos de Inclusão/ultraestrutura , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Lacticaseibacillus rhamnosus/ultraestrutura , Viabilidade Microbiana/efeitos dos fármacosRESUMO
BACKGROUND: Grape pomace is a source of phenolic compounds, which are associated with health benefits in humans. Additionally, fermented dairy foods with probiotics can be good vehicles to deliver these bioactive compounds. The effects of the addition of grape pomace extract (GPE) on the total phenolic (TP) content, physico-chemical characteristics and viability of Lactobacillus acidophilus LA-5 or Lactobacillus rhamnosus HN001 in fermented goat milks prepared with grape juice were investigated. RESULTS: The TP concentration increased significantly in fermented milks with the addition of GPE. A protective effect of GPE on the viability of L. acidophilus was observed. However, after 14 days of storage, the populations of L. acidophilus were significantly lower when compared with those of L. rhamnosus, and only the last probiotic maintained its viability above 7 log CFU mL-1 throughout the period investigated. The sensory scores of flavor, color and overall acceptability of the fermented milk containing L. rhamnosus HN001 were significantly increased when GPE was added. CONCLUSION: The use of GPE might increase the functionality of probiotic fermented goat milk processed with L. rhamnosus HN001 and grape juice because grape polyphenols are known for their antioxidant properties and positive effect on the modulation of gut microbiota. © 2016 Society of Chemical Industry.
Assuntos
Produtos Fermentados do Leite/análise , Manipulação de Alimentos/métodos , Frutas , Leite/metabolismo , Polifenóis/análise , Probióticos , Vitis , Animais , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Bifidobacterium/efeitos dos fármacos , Bifidobacterium/crescimento & desenvolvimento , Cor , Comportamento do Consumidor , Cabras , Humanos , Lactobacillus acidophilus/efeitos dos fármacos , Lactobacillus acidophilus/crescimento & desenvolvimento , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Lacticaseibacillus rhamnosus/crescimento & desenvolvimento , Fenóis/análise , PaladarRESUMO
The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl), a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10). Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal-Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05). The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control). The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.
Assuntos
Dispositivos para o Cuidado Bucal Domiciliar/microbiologia , Desinfecção/métodos , Escovação Dentária/instrumentação , Ácido Acético/química , Antibacterianos/química , Clorexidina/química , Contagem de Colônia Microbiana , Desinfetantes de Equipamento Odontológico/química , Escherichia coli/efeitos dos fármacos , Humanos , Imersão , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Estatísticas não Paramétricas , Streptococcus mutans/efeitos dos fármacos , Fatores de TempoRESUMO
The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl), a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10). Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal–Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05). The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control). The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.
Assuntos
Humanos , Dispositivos para o Cuidado Bucal Domiciliar/microbiologia , Desinfecção/métodos , Escovação Dentária/instrumentação , Ácido Acético/química , Antibacterianos/química , Contagem de Colônia Microbiana , Clorexidina/química , Desinfetantes de Equipamento Odontológico/química , Escherichia coli/efeitos dos fármacos , Imersão , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Estatísticas não Paramétricas , Staphylococcus aureus/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos , Fatores de TempoRESUMO
The use of essential oils (EOs) in functional foods containing probiotic microorganisms must consider the antimicrobial activity of these oils against beneficial bacteria such as Lactobacillus rhamnosus. This study aimed to evaluate the sensitivity of L. rhamnosus cultures treated with cinnamon EO through viable cell counts and visualisation by transmission electron microscopy. Cinnamon EO at a concentration of 0.04% had a bacteriostatic activity after 2 h of incubation. Although slight alterations were detected in the cell structure, this concentration was considered to be bactericidal, since it led to a significant reduction in cell numbers after 24 h. On the other hand, cinnamon EO at a 1.00% concentration decreased cell counts by 3 log units after 2 h incubation and no viable cell count was detected after 24 h. Transmission electron microscopy indicated that cells treated with 1.00% cinnamon EO were severely damaged and presented cell membrane disruption and cytoplasmic leakage.