Synthesis and characterization of new oligosaccharides with prebiotic activity

Detalhes bibliográficos
Autor(a) principal: Montenegro, Maria Inês Pereira
Data de Publicação: 2013
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10400.14/16300
Resumo: The importance of human intestinal microbiota in maintaining host health is well-known and in the past few decades, the consumer’s awareness for healthier foods has increased. There are several strategies to stimulate the proliferation of beneficial intestinal bacteria, including the consumption of prebiotics. Currently, there is a range of prebiotic carbohydrates on the market, most of them isolated from plant polysaccharides such as inulin and fructooligosaccharides (FOS) but there is an increasing interest in the development of new prebiotics, with added functionality. In this sense, chitosan, which is a polysaccharide composed of glucosamine (GlcN) and N-acetyl glucosamine (GlcNAc) units, linked by β (1→4) bonds, presents a structure very similar to prebiotic glucooligosaccharides. The main difference is the presence of amino groups, which are the cause of antimicrobial effect of chitosan. Chemical modification of chitosan by substitution of its amino groups could eliminate the antimicrobial effect and convert chitosan in a new interesting prebiotic ingredient. Thus, the objective of the present work is to chemically modify chitosan to be used in the food industry as prebiotic ingredient. In order to achieve this objective, the optimization of the synthesis of chitosan derivatives with glucose by the Maillard reaction and enzymatic hydrolysis, was conducted and the obtained purified derivatives were assayed for molar mass distribution and structural characterization by Size Exclusion Chromatography (SEC), Fourier Transform Infrared Spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance (1H-NMR) and colloid titration. The purified product was assayed for its prebiotic potential by means of in vitro fermentability assays performed with individual microbial strains and human faecal inocula. The experimental data showed that the refined chitooligosaccharide (COS) derivatives obtained in this work had potential prebiotic effects, inducing changes in both the pattern of generated metabolic products and the count of Bifidobacterium, which might contribute to a healthy intestinal environment. Finally, the in vitro cytotoxicity of the COS derivatives synthesized was performed by flow cytometry. The results obtained demonstrated that the COS derivatives are biocompatible molecules. Also, the assay showed that the substitution of the amino groups decreased the cytotoxicity of the COS derivatives when compared to unmodified COS. Nevertheless, further studies are recommended, mainly in vivo tests, to eventually confirm these in vitro results.
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spelling Synthesis and characterization of new oligosaccharides with prebiotic activityDomínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e TecnologiasDomínio/Área Científica::Engenharia e Tecnologia::Engenharia QuímicaThe importance of human intestinal microbiota in maintaining host health is well-known and in the past few decades, the consumer’s awareness for healthier foods has increased. There are several strategies to stimulate the proliferation of beneficial intestinal bacteria, including the consumption of prebiotics. Currently, there is a range of prebiotic carbohydrates on the market, most of them isolated from plant polysaccharides such as inulin and fructooligosaccharides (FOS) but there is an increasing interest in the development of new prebiotics, with added functionality. In this sense, chitosan, which is a polysaccharide composed of glucosamine (GlcN) and N-acetyl glucosamine (GlcNAc) units, linked by β (1→4) bonds, presents a structure very similar to prebiotic glucooligosaccharides. The main difference is the presence of amino groups, which are the cause of antimicrobial effect of chitosan. Chemical modification of chitosan by substitution of its amino groups could eliminate the antimicrobial effect and convert chitosan in a new interesting prebiotic ingredient. Thus, the objective of the present work is to chemically modify chitosan to be used in the food industry as prebiotic ingredient. In order to achieve this objective, the optimization of the synthesis of chitosan derivatives with glucose by the Maillard reaction and enzymatic hydrolysis, was conducted and the obtained purified derivatives were assayed for molar mass distribution and structural characterization by Size Exclusion Chromatography (SEC), Fourier Transform Infrared Spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance (1H-NMR) and colloid titration. The purified product was assayed for its prebiotic potential by means of in vitro fermentability assays performed with individual microbial strains and human faecal inocula. The experimental data showed that the refined chitooligosaccharide (COS) derivatives obtained in this work had potential prebiotic effects, inducing changes in both the pattern of generated metabolic products and the count of Bifidobacterium, which might contribute to a healthy intestinal environment. Finally, the in vitro cytotoxicity of the COS derivatives synthesized was performed by flow cytometry. The results obtained demonstrated that the COS derivatives are biocompatible molecules. Also, the assay showed that the substitution of the amino groups decreased the cytotoxicity of the COS derivatives when compared to unmodified COS. Nevertheless, further studies are recommended, mainly in vivo tests, to eventually confirm these in vitro results.A relevância da microbiota intestinal na manutenção da saúde do hospedeiro é bem conhecida e, nas últimas décadas, a consciencialização dos consumidores para a escolha de alimentos saudáveis tem vindo a aumentar. Existem diversas estratégias para estimular a proliferação de bactérias intestinais benéficas, incluindo o consumo de prebióticos. Atualmente, existe uma vasta gama de hidratos de carbono prebióticos no mercado, a maior parte isolados de polissacarídeos de plantas, de que são exemplo a inulina e frutooligossacarídeos (FOS). No entanto, existe um interesse crescente no desenvolvimento de novos prebióticos com funcionalidade adicional. Nesse sentido, o quitosano, sendo um polissacarídeo composto por unidades de glucosamina (GlcN) e N-acetil glucosamina (GlcNAc) unidas por ligações β (1→4), apresenta uma estrutura muito semelhante à dos atuais prebióticos glucooligossacarídeos. A diferença principal consiste na presença de grupos amina na sua estrutura, que lhe confere uma importante atividade antimicrobiana. A modificação química do quitosano por substituição dos seus grupos amina poderia eliminar este efeito antimicrobiano e converter o quitosano num novo e interessante ingrediente prebiótico. Assim, este trabalho teve por objetivo modificar quimicamente o quitosano para ser usado como ingrediente prebiótico na indústria alimentar. Por forma a atingir este objetivo, foi levada a cabo a otimização da síntese dos derivados do quitosano por reacção de Maillard e hidrólise enzimática. Os derivados obtidos foram analisados quanto à distribuição de massa molar e caracterizados estruturalmente por Cromatografia de Exclusão Molecular (SEC), Espectroscopia de Infravermeho por Transformada de Fourier (FT-IR), Ressonância Magnética Nuclear (1H-NMR) e titulação coloidal. O potencial prebiótico do produto purificado foi avaliado em ensaios de fermentação in vitro realizados em culturas puras e em inóculos humanos fecais. Os resultados obtidos demostraram que os quitooligossacarídeos (COS) sintetizados, possuem potenciais efeitos prebióticos, que incluem alterações no padrão de produtos metabólicos gerados e nas contagens de Bifidobacterium, podendo, assim, contribuir para um ambiente intestinal saudável. Por fim, a avaliação da citotoxicidade dos derivados de COS foi realizada in vitro por citometria de fluxo. Os resultados obtidos demonstraram que os derivados sintetizados são moléculas biocompatíveis e que a substituição dos grupos amina diminuiu a citotoxicidade dos derivados quando comparados com COS não modificados. No entanto, estudos in vivo são recomendados para confirmar estes resultados in vitro.Pintado, Maria Manuela EstevezCardelle-Cobas, AlejandraGullón, BeatrizVeritati - Repositório Institucional da Universidade Católica PortuguesaMontenegro, Maria Inês Pereira2015-01-19T14:55:10Z2014-04-1120132014-04-11T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10400.14/16300TID:201494671enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-10-24T01:33:37Zoai:repositorio.ucp.pt:10400.14/16300Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T18:13:31.684096Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Synthesis and characterization of new oligosaccharides with prebiotic activity
title Synthesis and characterization of new oligosaccharides with prebiotic activity
spellingShingle Synthesis and characterization of new oligosaccharides with prebiotic activity
Montenegro, Maria Inês Pereira
Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias
Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química
title_short Synthesis and characterization of new oligosaccharides with prebiotic activity
title_full Synthesis and characterization of new oligosaccharides with prebiotic activity
title_fullStr Synthesis and characterization of new oligosaccharides with prebiotic activity
title_full_unstemmed Synthesis and characterization of new oligosaccharides with prebiotic activity
title_sort Synthesis and characterization of new oligosaccharides with prebiotic activity
author Montenegro, Maria Inês Pereira
author_facet Montenegro, Maria Inês Pereira
author_role author
dc.contributor.none.fl_str_mv Pintado, Maria Manuela Estevez
Cardelle-Cobas, Alejandra
Gullón, Beatriz
Veritati - Repositório Institucional da Universidade Católica Portuguesa
dc.contributor.author.fl_str_mv Montenegro, Maria Inês Pereira
dc.subject.por.fl_str_mv Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias
Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química
topic Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias
Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química
description The importance of human intestinal microbiota in maintaining host health is well-known and in the past few decades, the consumer’s awareness for healthier foods has increased. There are several strategies to stimulate the proliferation of beneficial intestinal bacteria, including the consumption of prebiotics. Currently, there is a range of prebiotic carbohydrates on the market, most of them isolated from plant polysaccharides such as inulin and fructooligosaccharides (FOS) but there is an increasing interest in the development of new prebiotics, with added functionality. In this sense, chitosan, which is a polysaccharide composed of glucosamine (GlcN) and N-acetyl glucosamine (GlcNAc) units, linked by β (1→4) bonds, presents a structure very similar to prebiotic glucooligosaccharides. The main difference is the presence of amino groups, which are the cause of antimicrobial effect of chitosan. Chemical modification of chitosan by substitution of its amino groups could eliminate the antimicrobial effect and convert chitosan in a new interesting prebiotic ingredient. Thus, the objective of the present work is to chemically modify chitosan to be used in the food industry as prebiotic ingredient. In order to achieve this objective, the optimization of the synthesis of chitosan derivatives with glucose by the Maillard reaction and enzymatic hydrolysis, was conducted and the obtained purified derivatives were assayed for molar mass distribution and structural characterization by Size Exclusion Chromatography (SEC), Fourier Transform Infrared Spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance (1H-NMR) and colloid titration. The purified product was assayed for its prebiotic potential by means of in vitro fermentability assays performed with individual microbial strains and human faecal inocula. The experimental data showed that the refined chitooligosaccharide (COS) derivatives obtained in this work had potential prebiotic effects, inducing changes in both the pattern of generated metabolic products and the count of Bifidobacterium, which might contribute to a healthy intestinal environment. Finally, the in vitro cytotoxicity of the COS derivatives synthesized was performed by flow cytometry. The results obtained demonstrated that the COS derivatives are biocompatible molecules. Also, the assay showed that the substitution of the amino groups decreased the cytotoxicity of the COS derivatives when compared to unmodified COS. Nevertheless, further studies are recommended, mainly in vivo tests, to eventually confirm these in vitro results.
publishDate 2013
dc.date.none.fl_str_mv 2013
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2014-04-11T00:00:00Z
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