Avaliação de diferentes prebióticos, probióticos e seus metabólitos na inibição de bactérias patogênicas e potenciais aplicações na preservação de alimentos e benefícios à saúde.
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Data
2021-10-06
Autores
Figueiredo, Franciane Cristina de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A microbiota intestinal tem papel fundamental na saúde, sendo os suplementos alimentares e outros produtos que proporcionam equilíbrio à microbiota intestinal amplamente estudados nos dias atuais. Dentre esses produtos, destacam-se os probióticos, prebióticos e pós-bióticos. Probióticos são definidos como microrganismos vivos que, quando ingeridos em quantidades adequadas, afetam positivamente a saúde do hospedeiro. Os prebióticos são substratos que alcançam a microbiota intestinal intacta e são capazes de estimular seletivamente o crescimento de probióticos. Postbiotics, contudo, é um novo conceito que define extratos ou sobrenadantes de origem probiótica, livres de células e benéficos à saúde. Esses ingredientes são apresentados como possíveis alternativas ao uso de antibióticos ou podem atuar como conservantes de alimentos, evitando o crescimento de bactérias patogênicas como Salmonella enterica serovar Typhimurium, Escherichia coli e Staphylococcus aureus, responsáveis por infecções graves. A presente tese teve como objetivo avaliar a inibição dessas bactérias patogênicas por esses ingredientes alimentícios, aplicados isoladamente ou em mistura. Além disso, a estabilidade da atividade antimicrobiana foi avaliada em diferentes condições, juntamente com a caracterização de ácidos orgânicos e testes de aumento de escala. As cepas probióticas foram Bifidobacterium animalis, B. breve, B. lactis, B. longum, Lactobacillus acidophilus e Levilactobacillus. brevis. E. coli foi inibida por todos os postbiotics, tanto isoladamente quanto em misturas. Nenhum postbiotic em dosagens de 6% (v / v) foi capaz de inibir S. aureus. Para Salmonella typhimurium, os postbiotics de B. animalis, B. breve e B. lactis inibiram com sucesso o crescimento do patógeno. Testes com a mistura dos prebióticos frutooligossacarídeos (FOS) e xilooligossacarídeos (XOS) mostraram que, com 10h de cultivo, apenas L. brevis e B. longum foram estimulados, superando o crescimento do controle (glicose). A mistura postbiotic de todas as linhagens de Bifidobacterium inibiu com sucesso o crescimento de Salmonella, entretanto, a adição de postbiotic de Lactobacillus e Levilactobacillus à mistura diminuiu sua atividade inibitória, mostrando um possível antagonismo entre os gêneros. Nenhum postbiotic inibiu o crescimento de qualquer bactéria probiótica, mostrando o potencial para o uso combinado de postbiotic e prebióticos. Os testes de estabilidade revelaram atividade inibitória dos postbiotics após tratamentos com alta temperatura, exceto para os postbiotics de B. longum, provavelmente devido à sua bacteriocina não termo-resistente. Quatro ácidos orgânicos (acético, lático, succínico e fórmico) estiveram presentes em todos os postbiotics, com os ácidos acético e lático presentes em maiores concentrações. Os testes em diferentes faixas de pH revelaram que os ácidos orgânicos apresentam atividade inibitória quando em pH ácido, devido à sua presença na forma indissociada, capaz de entrar na parede celular da bactéria e se dissociar no interior da célula, matando o patógeno. Testes de aumento de escala para fermentadores de 2 litros mostraram que postbiotics da linhagem de B. breve com atividade inibitória satisfatória podem ser produzidos em 24 horas. A concentração de 6% (v / v) deste postbiotic em meio BG contendo açúcares comerciais inibiu com sucesso o crescimento de Salmonella typhimurium, mesmo na presença de açúcares de fácil fermentação. Postibiotic secos de B. breve em estufa (105º C) apresentaram atividade inibitória semelhante com concentrações de 0,9% (m / v). Embora mais estudos sejam necessários para esclarecer a complexa interação dos metabólitos presentes nos postbiotics, a estabilidade da atividade inibitória dessas substâncias após tratamentos com altas temperaturas, baixo pH e após secagem é um atributo que destaca seu potencial de utilização na indústria alimentícia.
Intestinal microbiota has a crucial role in health, with food supplements and other products that provide balance to the intestinal microbiota being thoroughly studied in the present day. Among such products, probiotics, prebiotics and postbiotics stand out. Probiotics are defined as living microorganisms that, when ingested in adequate quantities, positively affect the health of the host. Prebiotics are substrates that reach the intestinal microbiota intact and are capable of selectively stimulating the growth of probiotics. Postbiotics, on the other hand, is a new concept, defining extracts or supernatants of probiotic origin, cell-free and beneficial to health. These ingredients are presented as possible alternatives to the usage of antibiotics or may act as food preservatives, preventing the growth of pathogenic bacteria such as Salmonella enterica serovar Typhimurium, Escherichia coli and Staphylococcus aureus, responsible for severe infections. The present thesis aimed to assess the inhibition of these pathogenic bacteria by these food ingredientes, applied either singly or in mixtures. In addition, the stability of antimicrobial activity was assessed in different conditions, along with the characterization of organic acids and scale-up tests. Probiotic strains were Bifidobacterium animalis, B. breve, B. lactis, B. longum, Lactobacillus acidophilus and Levilactobacillus brevis. E. coli was inhibited by all postbiotics, both singly and in mixtures. No postbiotic at dosages of 6% (v/v) was capable of inhibiting S. aureus. For Salmonella typhimurium, the postbiotics of B. animalis, B. breve and B. lactis successfully inhibited the pathogen’s growth. Tests with the mixture of the prebiotics fructooligosacharides (FOS) and xylooligosacharides (XOS) showed that, with 10h of culture, only L. brevis and B. longum were stimulated, exceeding the growth of control (glucose). The postbiotic mixture of all Bifidobacterium strains successfully inhibited Salmonella’s growth as well; however, adding postbiotics from Lactobacillus and Levilactobacillus strains to the mixture lessened its inhibitory activity, showing a possible antagonism between genera. No postbiotics inhibited the growth of any probiotic bacteria, showing the potential for combined use of postbiotics and prebiotics. The stability tests revealed inhibitory activity of postbiotics after treatments with high temperature, except for the postbiotics of B. longum, probably due to its non-thermo-resistant bacteriocin. Four organic acids (acetic, lactic, succinic and formic) were present in all postbiotics, with acetic and lactic acid present in higher concentrations. The tests in different pH ranges revealed that organic acids show inhibitory activity when in acid pH, due to their presence in their undissociated form, capable of entering the pathogen’s cell-wall and dissociating inside the cell, killing the pathogen. Scale-up tests to 2-liter fermenters showed that postbiotics from the B. breve strain with satisfactory inhibitory activity can be produced in 24 hours. The concentration of 6% (v/v) of this postbiotic in BG medium containing commercial sugars successfully inhibited the growth of Salmonella typhimurium, even in the presence of easily fermented sugars. Oven-dried (105º C) B. breve postbiotics showed similar inhibitory activity with concentrations of 0.9% (m/v). Although further studies are necessary to clarify the complex interaction of metabolites present in postbiotics, the stability of the inhibitory activity of these substances after treatments with high temperatures, low pH and after drying is an attribute that highlights their potential usage in the food industry.
Intestinal microbiota has a crucial role in health, with food supplements and other products that provide balance to the intestinal microbiota being thoroughly studied in the present day. Among such products, probiotics, prebiotics and postbiotics stand out. Probiotics are defined as living microorganisms that, when ingested in adequate quantities, positively affect the health of the host. Prebiotics are substrates that reach the intestinal microbiota intact and are capable of selectively stimulating the growth of probiotics. Postbiotics, on the other hand, is a new concept, defining extracts or supernatants of probiotic origin, cell-free and beneficial to health. These ingredients are presented as possible alternatives to the usage of antibiotics or may act as food preservatives, preventing the growth of pathogenic bacteria such as Salmonella enterica serovar Typhimurium, Escherichia coli and Staphylococcus aureus, responsible for severe infections. The present thesis aimed to assess the inhibition of these pathogenic bacteria by these food ingredientes, applied either singly or in mixtures. In addition, the stability of antimicrobial activity was assessed in different conditions, along with the characterization of organic acids and scale-up tests. Probiotic strains were Bifidobacterium animalis, B. breve, B. lactis, B. longum, Lactobacillus acidophilus and Levilactobacillus brevis. E. coli was inhibited by all postbiotics, both singly and in mixtures. No postbiotic at dosages of 6% (v/v) was capable of inhibiting S. aureus. For Salmonella typhimurium, the postbiotics of B. animalis, B. breve and B. lactis successfully inhibited the pathogen’s growth. Tests with the mixture of the prebiotics fructooligosacharides (FOS) and xylooligosacharides (XOS) showed that, with 10h of culture, only L. brevis and B. longum were stimulated, exceeding the growth of control (glucose). The postbiotic mixture of all Bifidobacterium strains successfully inhibited Salmonella’s growth as well; however, adding postbiotics from Lactobacillus and Levilactobacillus strains to the mixture lessened its inhibitory activity, showing a possible antagonism between genera. No postbiotics inhibited the growth of any probiotic bacteria, showing the potential for combined use of postbiotics and prebiotics. The stability tests revealed inhibitory activity of postbiotics after treatments with high temperature, except for the postbiotics of B. longum, probably due to its non-thermo-resistant bacteriocin. Four organic acids (acetic, lactic, succinic and formic) were present in all postbiotics, with acetic and lactic acid present in higher concentrations. The tests in different pH ranges revealed that organic acids show inhibitory activity when in acid pH, due to their presence in their undissociated form, capable of entering the pathogen’s cell-wall and dissociating inside the cell, killing the pathogen. Scale-up tests to 2-liter fermenters showed that postbiotics from the B. breve strain with satisfactory inhibitory activity can be produced in 24 hours. The concentration of 6% (v/v) of this postbiotic in BG medium containing commercial sugars successfully inhibited the growth of Salmonella typhimurium, even in the presence of easily fermented sugars. Oven-dried (105º C) B. breve postbiotics showed similar inhibitory activity with concentrations of 0.9% (m/v). Although further studies are necessary to clarify the complex interaction of metabolites present in postbiotics, the stability of the inhibitory activity of these substances after treatments with high temperatures, low pH and after drying is an attribute that highlights their potential usage in the food industry.
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Palavras-chave
Probióticos, Prebióticos, Microbiologia, Microbiota, Alimentos funcionais, Probiotics, Prebiotics, Microbiology, Functional foods