The Experts below are selected from a list of 504 Experts worldwide ranked by ideXlab platform
Moita, Suelen Ribeiro - One of the best experts on this subject based on the ideXlab platform.
-
Peptídeos biologicamente ativos extraídos de diferentes tipos de queijos e avaliados por meio de espectrometria de massa
2012Co-Authors: Moita, Suelen RibeiroAbstract:Peptídeos bioativos (PBA) são fragmentos de proteínas que exercem uma determinada atividade ao interagirem com células específicas no organismo desencadeando respostas bioquímicas e fisiológicas. Esses peptídeos são inativos dentro da cadeia proteica intacta, mas podem ser liberados por mecanismos de proteólise tornando-se ativos. Peptídeos bioativos têm sido isolados de diversos alimentos de origem animal, como carnes e ovos, e origem vegetal, como algas e soja. Os alimentos de origem láctea têm apresentado um destaque nos estudos com PBA, pois as proteínas do leite são as que disponibilizam maior variedade de peptídeos com atividade biológica. Considerando o leite como um alimento que apresenta propriedades nutricionais importantes, sendo o precursor de diversos alimentos apreciados pelo homem, como os queijos, o presente estudo teve como objetivo avaliar os peptídeos provenientes de diferentes tipos de queijos preparados sob diferentes condições e atividade microbiológica, possuindo propriedades sensoriais distintas, embora originados de uma mesma fonte de proteínas. O estudo foi realizado com queijos dos tipos minas meia cura, requeijão, provolone, parmesão, coalho, prato, minas frescal e mussarela, coletados em uma feira do Distrito Federal. Os procedimentos para a extração dos peptídeos das amostras foram realizados utilizando solventes polares e apolares e em seguida, as amostras resultantes foram analisadas por espectrometria de massa MALDI-TOF e TOF/TOF. Os resultados indicaram a presença de uma variedade de peptídeos extraídos de cada amostra de queijo a partir dos solventes escolhidos, sendo um fator que possibilita a identificação e distinção dos diferentes tipos de queijo, com base em suas características moleculares, considerando que determinados peptídeos foram detectados em todas e outros apenas em algumas amostras. Os resultados obtidos foram avaliados por meio do método de estatística multivariada, o qual permitiu a distinção entre os diferentes queijos, bem como o seu agrupamento com base em suas características moleculares. A revisão da literatura com foco na presente abordagem mostrou a origem protéica de alguns dos peptídeos extraídos, tais como os resíduos de aminoácidos aos quais constituem. Deste modo, o presente estudo mostrou que é possível a utilização desta abordagem experimental com a finalidade de distinguir queijos de diferentes tipos, com a perspectiva de identificação de queijos com base nas propriedades biológicas inerentes a peptídeos específicos encontrados nesse derivado lácteo. _________________________________________________________________________________ ABSTRACTBioactive peptides (PBA) are fragments of protein that perform a particular activity by interacting with specific cells in the body producing biochemical and physiological responses. These peptides are inactive within protein chain intact, but can be released by proteolysis mechanisms becoming active. Bioactive peptides have been isolated from various foods of animal origin such as meat and eggs, and vegetable origin, such as algae and soybeans. The dairy products have presented an emphasis on studies with PBA because milk proteins offer greater variety of biologically active peptides. Whereas milk as a food which has important nutritional properties, being the precursor of many products enjoyed by human, such as Cheeses, the present study aimed to evaluate the peptides from several types of Cheeses produced at different conditions and microbial activity, having distinct sensory properties, although originated from the same source of protein. This study was carried out with different types of Cheese, such as half cure Cheese, cream Cheese, provolone Cheese, Parmesan Cheese, curd Cheese, minas fresh Cheese and mozzarella, collected in the Distrito Federal (Brazil) fair. The procedures for extraction of peptides were performed using polar and nonpolar solvents, and the results were analyzed by mass spectrometry MALDI-TOF and TOF / TOF. The results indicated the presence of a variety of peptides extracted from each sample Cheese from the solvents chosen, being a factor that allows the identification and distinction of different types of Cheese, based on their molecular characteristics, considering that certain peptides were detected at all and others only in some samples. The results were evaluated by multivariate statistical analysis which allowed the distinction among the different Cheeses, as well as grouping based on their molecular characteristics. The literature review focused on present approach showed the origin of protein of some extracted peptides, such as amino acid residues which constitute them. Thus, this study showed that it is possible to use this experimental approach in order to distinguish different types of Cheeses, with a view to identifying Cheeses based on biological properties inherent to specific peptides found in dairy products
-
Peptídeos biologicamente ativos extraídos de diferentes tipos de queijos e avaliados por meio de espectrometria de massa
2011Co-Authors: Moita, Suelen RibeiroAbstract:Monografia (graduação)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, 2011.Peptídeos bioativos (PBA) são fragmentos de proteínas que exercem uma determinada atividade ao interagirem com células específicas no organismo desencadeando respostas bioquímicas e fisiológicas. Esses peptídeos são inativos dentro da cadeia proteica intacta, mas podem ser liberados por mecanismos de proteólise tornando-se ativos. Peptídeos bioativos têm sido isolados de diversos alimentos de origem animal, como carnes e ovos, e origem vegetal, como algas e soja. Os alimentos de origem láctea têm apresentado um destaque nos estudos com PBA, pois as proteínas do leite são as que disponibilizam maior variedade de peptídeos com atividade biológica. Considerando o leite como um alimento que apresenta propriedades nutricionais importantes, sendo o precursor de diversos alimentos apreciados pelo homem, como os queijos, o presente estudo teve como objetivo avaliar os peptídeos provenientes de diferentes tipos de queijos preparados sob diferentes condições e atividade microbiológica, possuindo propriedades sensoriais distintas, embora originados de uma mesma fonte de proteínas. O estudo foi realizado com queijos dos tipos minas meia cura, requeijão, provolone, parmesão, coalho, prato, minas frescal e mussarela, coletados em uma feira do Distrito Federal. Os procedimentos para a extração dos peptídeos das amostras foram realizados utilizando solventes polares e apolares e em seguida, as amostras resultantes foram analisadas por espectrometria de massa MALDI-TOF e TOF/TOF. Os resultados indicaram a presença de uma variedade de peptídeos extraídos de cada amostra de queijo a partir dos solventes escolhidos, sendo um fator que possibilita a identificação e distinção dos diferentes tipos de queijo, com base em suas características moleculares, considerando que determinados peptídeos foram detectados em todas e outros apenas em algumas amostras. Os resultados obtidos foram avaliados por meio do método de estatística multivariada, o qual permitiu a distinção entre os diferentes queijos, bem como o seu agrupamento com base em suas características moleculares. A revisão da literatura com foco na presente abordagem mostrou a origem protéica de alguns dos peptídeos extraídos, tais como os resíduos de aminoácidos aos quais constituem. Deste modo, o presente estudo mostrou que é possível a utilização desta abordagem experimental com a finalidade de distinguir queijos de diferentes tipos, com a perspectiva de identificação de queijos com base nas propriedades biológicas inerentes a peptídeos específicos encontrados nesse derivado lácteo. _________________________________________________________________________________ ABSTRACTBioactive peptides (PBA) are fragments of protein that perform a particular activity by interacting with specific cells in the body producing biochemical and physiological responses. These peptides are inactive within protein chain intact, but can be released by proteolysis mechanisms becoming active. Bioactive peptides have been isolated from various foods of animal origin such as meat and eggs, and vegetable origin, such as algae and soybeans. The dairy products have presented an emphasis on studies with PBA because milk proteins offer greater variety of biologically active peptides. Whereas milk as a food which has important nutritional properties, being the precursor of many products enjoyed by human, such as Cheeses, the present study aimed to evaluate the peptides from several types of Cheeses produced at different conditions and microbial activity, having distinct sensory properties, although originated from the same source of protein. This study was carried out with different types of Cheese, such as half cure Cheese, cream Cheese, provolone Cheese, Parmesan Cheese, curd Cheese, minas fresh Cheese and mozzarella, collected in the Distrito Federal (Brazil) fair. The procedures for extraction of peptides were performed using polar and nonpolar solvents, and the results were analyzed by mass spectrometry MALDI-TOF and TOF / TOF. The results indicated the presence of a variety of peptides extracted from each sample Cheese from the solvents chosen, being a factor that allows the identification and distinction of different types of Cheese, based on their molecular characteristics, considering that certain peptides were detected at all and others only in some samples. The results were evaluated by multivariate statistical analysis which allowed the distinction among the different Cheeses, as well as grouping based on their molecular characteristics. The literature review focused on present approach showed the origin of protein of some extracted peptides, such as amino acid residues which constitute them. Thus, this study showed that it is possible to use this experimental approach in order to distinguish different types of Cheeses, with a view to identifying Cheeses based on biological properties inherent to specific peptides found in dairy products
Thomas Hofmann - One of the best experts on this subject based on the ideXlab platform.
-
Quantitation of Key Tastants and Re-engineering the Taste of Parmesan Cheese
Journal of agricultural and food chemistry, 2016Co-Authors: Hedda Hillmann, Thomas HofmannAbstract:Targeted quantitation of 65 candidate taste compounds and ranking on the basis of dose-over-threshold (DoT) factors, followed by taste re-engineering and omission experiments in aqueous solution as well as in a Cheese-like model matrix, led to the identification of a total of 31 key tastants (amino acids, organic acids, fatty acids, biogenic amines, and minerals) with DoT factors ≥1.0 and a total of 15 subthreshold, but kokumi-enhancing, γ-glutamyl peptides in extraordinarily high concentrations of 20468 μmol/kg. Among the γ-glutamyl peptides, γ-Glu-Gly, γ-Glu-Ala, γ-Glu-Thr, γ-Glu-Asp, γ-Glu-Lys, γ-Glu-Glu, γ-Glu-Trp, γ-Glu-Gln, and γ-Glu-His have been identified for the first time in Parmesan Cheese. The excellent match of the sensory profile of the taste recombinants and the authentic Cheese demonstrated the identified taste compounds to be fully sufficient to create the characteristic taste profile of the Parmesan Cheese. This molecular blueprint of a Parmesan’s chemosensory signature might be a usefu...
-
formation of kokumi enhancing γ glutamyl dipeptides in Parmesan Cheese by means of γ glutamyltransferase activity and stable isotope double labeling studies
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Hedda Hillmann, Rudi F. Vogel, Jurgen Behr, Matthias A Ehrmann, Thomas HofmannAbstract:Recently, γ-glutamyl dipeptides (γ-GPs) were found to be responsible for the attractive kokumi flavor of Parmesan Cheese (PC). Quantitation of γ-GPs and their parent amino acids in 13-, 24-, and 30-month ripened PC samples by LC-MS/MS and stable isotope dilution analysis (SIDA), in-Cheese 13C-labeling studies, followed by analysis of the γ-glutamyl transferase (GGT) activity revealed γ-GPs to be generated most efficiently after 24 months of ripening by a GGT-catalyzed transfer of the γ-glutamyl moiety of l-glutamine onto various acceptor amino acids released upon casein proteolysis. Following the identification of milk as a potential GGT source in PC, the functionality of the milk’s GGT to generate the target γ-GPs was validated by stable isotope double-labeling (SIDL) experiments. Therefore, raw and heat-treated milk samples were incubated with l-glutamine-[U-13C] and acceptor amino acids (X) and the hetero- (γ-Glu-[13C5]-X) and homotranspeptidation products (γ-Glu-Gln-[13C10]) were quantitated by LC-MS/...
-
Formation of Kokumi-Enhancing γ‑Glutamyl Dipeptides in Parmesan Cheese by Means of γ‑Glutamyltransferase Activity and Stable Isotope Double-Labeling Studies
2016Co-Authors: Hedda Hillmann, Jürgen Behr, Matthias A. Ehrmann, Rudi F. Vogel, Thomas HofmannAbstract:Recently, γ-glutamyl dipeptides (γ-GPs) were found to be responsible for the attractive kokumi flavor of Parmesan Cheese (PC). Quantitation of γ-GPs and their parent amino acids in 13-, 24-, and 30-month ripened PC samples by LC-MS/MS and stable isotope dilution analysis (SIDA), in-Cheese 13C-labeling studies, followed by analysis of the γ-glutamyl transferase (GGT) activity revealed γ-GPs to be generated most efficiently after 24 months of ripening by a GGT-catalyzed transfer of the γ-glutamyl moiety of l-glutamine onto various acceptor amino acids released upon casein proteolysis. Following the identification of milk as a potential GGT source in PC, the functionality of the milk’s GGT to generate the target γ-GPs was validated by stable isotope double-labeling (SIDL) experiments. Therefore, raw and heat-treated milk samples were incubated with l-glutamine-[U-13C] and acceptor amino acids (X) and the hetero- (γ-Glu-[13C5]-X) and homotranspeptidation products (γ-Glu-Gln-[13C10]) were quantitated by LC-MS/MS-SIDA using γ-Glu-Ala-[13C3] as the internal standard. High GGT activity to generate the γ-GPs and preference for l-phenylalanine and l-methionine as acceptor amino acids were found in raw milk and milk samples heat-treated for 10 min up to a maximum of 65 °C. In comparison, GGT activity and SIDL studies performed with inoculated Lactobacillus strains, including Lactobacillus harbinensis and Lactobacillus casei identified in PC by means of 16S rRNA gene sequencing, did not show any significant GGT activity and unequivocally demonstrated unpasteurized cow’s milk, rather than microorganisms, as a key factor in γ-glutamyl dipeptide generation in Parmesan Cheese
Analice Claudia De Azevedo - One of the best experts on this subject based on the ideXlab platform.
-
queijo parmesao caracterizacao fisico quimica microbiologica e microestrutura Parmesan Cheese physicochemical and microbiological quality and microstructure
2011Co-Authors: Analice Claudia De Azevedo, Luiz Roberto, Sebastiao Roberto Taboga, Ana Lucia, Barretto PennaAbstract:Changes in Parmesan Cheese during ripening can be detected by chemical, microbiological, and microscopic analysis. This study aimed to evaluate the physicochemical and microbiological quality of milk and Cheeses, as well as to evaluate the microstructure of Parmesan Cheese during 180 days of ripening. All samples exhibited physicochemical and microbiological characteristics in accordance with the Brazilian standards. There was an increase in titratable acidity, depth, and extension ripening indices, and also in the tyrosine and tryptophan contents. The microstructure analysis showed the presence of crystals, debris, and interactions between starter cultures and fat globules. At the end of the Cheese ripening process, a dense and compact casein matrix was observed.
-
Liberação das enzimas LDH e PepX e evolução da maturação de queijo parmesão adicionado de culturas autolíticas de Lactobacilus helveticus
Universidade Estadual Paulista (UNESP), 2009Co-Authors: Analice Claudia De AzevedoAbstract:O parmesão é um queijo típico italiano e possui como características peculiares o baixo teor de umidade, a textura granular e o sabor picante. Seu processamento é sempre lembrado pelo longo período de maturação e durante esta etapa ocorrem numerosas reações bioquímicas de degradação de seus componentes pelas enzimas oriundas do leite e do coalho e daquelas produzidas pelas bactérias, causando mudanças na textura e sabor desse produto. A autólise espontânea de microrganismos termófilos, como Lactobacillus helveticus, é uma característica tecnológica importante para a escolha de culturas com potencial de aplicação na fabricação de queijos de massa dura como o Parmesão. Desta forma o objetivo do presente trabalho é avaliar, durante a maturação do queijo Parmesão, o desempenho autolítico de culturas de Lb. helveticus autóctones, previamente isoladas de soro fermento. Foram utilizadas as culturas autóctones de Lb. helveticus, E5 com perfil autolítico elevado e A e D1 com perfil autolítico intermediário. A cultura comercial Cc1 (Lh-B02, Chr. Hansen) com perfil autolítico elevado foi utilizada como controle. A atividade das enzimas intracelulares LDH e PepX, bem como a viabilidade foram realizadas durante 48 horas de crescimento das culturas. Após a elaboração dos queijos com as diferentes culturas, mensalmente, foi determinada a contagem de lactobacilos termófilos, a atividade das enzimas LDH e PepX, a evolução dos teores de acidez, tirosina, triptofano e índice de maturação no queijo Parmesão ao longo de 180 dias de maturação. A maior liberação das enzimas LDH e PepX in vitro foi observada na cultura comercial Cc1 e autóctone E5 e comportamento semelhante entre as análises de CDM e cultivo em placa foi observado apenas para a cultura autóctone A e cultivo comercial Cc1. A maior população de lactobacilos termófilos nos queijos experimentais...The Parmesan is a typical Italian Cheese and has peculiar characteristics such as low moisture level, a granular texture and spicy flavor. Its processing involves long period of ripening and during this stage there are many biochemical reactions produced by enzymes from the raw milk, rennet and those produced by bacteria, resulting in changes in texture and taste of this product. The spontaneous autolysis of thermophilous microorganisms, such as Lactobacillus helveticus, is an important technological feature for the choice of cultures with potential application in the production of hard Cheeses, such as Parmesan. The objective of this study was to assess the autolytic performance of cultures of autochthonous Lb. helveticus, previously isolated from natural whey starter during the ripening of Parmesan Cheese. Autochthonous cultures of Lb. helveticus, E5 with high autolytic profile and A and D1 with intermediary autolytic profile were used. The commercial culture Cc1 (Lh-B02, Chr. Hansen) with high autolitic profile was used as control. The activity of in situ intracellular enzymes LDH and PepX, and the cell viability after 48 hours of growth were determined. Every month during the 180 days of ripening the population of thermophilous lactobacilli, the activity of enzymes LDH and PepX, the acidity, tyrosine, tryptophan contents and the index of ripening on Parmesan Cheese were determined. The highest release in vitro of the LDH and PepX enzymes was observed in the commercial culture Cc1 and autocthonous E5 and similar culture A and the commercial culture Cc1. The highest population of thermophilous lactobacilli in the experimental Cheeses was observed at the 30 days of ripening. In all Cheeses samples it was observed in the Cheeses produced with cultures with higher autolytic profile. There was a significant increase in acidity, tyrosine and tryptophan contents and IR in all samples... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
-
avaliacao do aspecto sanitario e microbiota latica durante a maturacao do queijo parmesao evaluation of sanitary quality and lactic microbiota during Parmesan Cheese ripening
2008Co-Authors: Jupyracyara J. C. Barros, Analice Claudia De Azevedo, Ana Lucia, Daise Aparecida Rossi, Celso Jose De Moura, Barretto PennaAbstract:1 Doutoranda do Programa de Pos-graduacao em Engenharia e Ciencia de Alimentos. UNESP Universidade Estadual Paulista “Julio de Mesquita Filho”, IBILCE, Departamento de Engenharia e Tecnologia de Alimentos, Rua Cristovao Colombo, 2265, 15054-000, Sao Jose do Rio Preto SP, Brasil, jupyscbarros@hotmail.com 2 Mestranda do Programa de Pos-graduacao em Engenharia e Ciencia de Alimentos. UNESP Universidade Estadual Paulista “Julio de Mesquita Filho”, IBILCE, Departamento de Engenharia e Tecnologia de Alimentos, Rua Cristovao Colombo, 2265, 15054-000, Sao Jose do Rio Preto SP, Brasil, analiceazevedo@hotmail.com 3 Doutora em Ciencia dos Alimentos. UFU Universidade Federal de Uberlândia, Faculdade de Medicina Veterinaria, Campus Uberlândia, Avenida Ceara, s/n, 38402-018, Uberlândia MG, Brasil, daiser@umuarama.ufu.br 4 Doutor em Ciencia dos Alimentos. UFG Universidade Federal de Goias, Escola de Agronomia e Engenharia de Alimentos, Campus Samambaia, Rodovia Goiânia/Nova Veneza, Km 0, 74001-970, Goiânia GO, cjdmoura@agro.ufg.br 5 Doutora em Tecnologia Bioquimico Farmaceutica Area de Tecnologia de Alimentos. UNESP Universidade Estadual Paulista “Julio de Mesquita Filho”, IBILCE, Departamento de Engenharia e Tecnologia de Alimentos, Rua Cristovao Colombo, 2265, 15054-000, Sao Jose do Rio Preto SP, Brasil, analucia@ibilce.unesp.br AVALIACAO DO ASPECTO SANITARIO E MICROBIOTA LATICA DURANTE A MATURACAO DO QUEIJO PARMESAO
Azevedo, Analice Cláudia De [unesp] - One of the best experts on this subject based on the ideXlab platform.
-
Parmesan Cheese: physicochemical and microbiological quality and microstructure
Sociedade Brasileira de Ciência e Tecnologia de Alimentos, 2011Co-Authors: Barros, Jupyracyara Jandyra De Carvalho [unesp], Azevedo, Analice Cláudia De [unesp], Faleiros Júnior, Luiz Roberto [unesp], Taboga, Sebastião Roberto [unesp], Penna, Ana Lúcia Barretto [unesp]Abstract:Mudanças no queijo Parmesão durante a maturação podem ser avaliadas por análises químicas, microbiológicas e microscópicas. Este estudo teve por objetivo efetuar a caracterização físico-química e microbiológica do leite e do queijo Parmesão, assim como sua microestrutura, durante 180 dias de maturação. Todas as amostras exibiram características físico-químicas e microbiológicas de acordo com a legislação brasileira. Ocorreu aumento na acidez titulável, nos índices de extensão e profundidade da maturação e nos teores de tirosina e triptofano. A análise da microestrutura demonstra a presença de cristais, debris, e a interação entre as culturas startere os glóbulos de gordura. No final da maturação, a matriz de caseína apresentava-se densa e compactaChanges in Parmesan Cheese during ripening can be detected by chemical, microbiological, and microscopic analysis. This study aimed to evaluate the physicochemical and microbiological quality of milk and Cheeses, as well as to evaluate the microstructure of Parmesan Cheese during 180 days of ripening. All samples exhibited physicochemical and microbiological characteristics in accordance with the Brazilian standards. There was an increase in titratable acidity, depth, and extension ripening indices, and also in the tyrosine and tryptophan contents. The microstructure analysis showed the presence of crystals, debris, and interactions between starter cultures and fat globules. At the end of the Cheese ripening process, a dense and compact casein matrix was observe
-
Liberação das enzimas LDH e PepX e evolução da maturação de queijo parmesão adicionado de culturas autolíticas de Lactobacilus helveticus
Universidade Estadual Paulista (UNESP), 2009Co-Authors: Azevedo, Analice Cláudia De [unesp]Abstract:O parmesão é um queijo típico italiano e possui como características peculiares o baixo teor de umidade, a textura granular e o sabor picante. Seu processamento é sempre lembrado pelo longo período de maturação e durante esta etapa ocorrem numerosas reações bioquímicas de degradação de seus componentes pelas enzimas oriundas do leite e do coalho e daquelas produzidas pelas bactérias, causando mudanças na textura e sabor desse produto. A autólise espontânea de microrganismos termófilos, como Lactobacillus helveticus, é uma característica tecnológica importante para a escolha de culturas com potencial de aplicação na fabricação de queijos de massa dura como o Parmesão. Desta forma o objetivo do presente trabalho é avaliar, durante a maturação do queijo Parmesão, o desempenho autolítico de culturas de Lb. helveticus autóctones, previamente isoladas de soro fermento. Foram utilizadas as culturas autóctones de Lb. helveticus, E5 com perfil autolítico elevado e A e D1 com perfil autolítico intermediário. A cultura comercial Cc1 (Lh-B02, Chr. Hansen) com perfil autolítico elevado foi utilizada como controle. A atividade das enzimas intracelulares LDH e PepX, bem como a viabilidade foram realizadas durante 48 horas de crescimento das culturas. Após a elaboração dos queijos com as diferentes culturas, mensalmente, foi determinada a contagem de lactobacilos termófilos, a atividade das enzimas LDH e PepX, a evolução dos teores de acidez, tirosina, triptofano e índice de maturação no queijo Parmesão ao longo de 180 dias de maturação. A maior liberação das enzimas LDH e PepX in vitro foi observada na cultura comercial Cc1 e autóctone E5 e comportamento semelhante entre as análises de CDM e cultivo em placa foi observado apenas para a cultura autóctone A e cultivo comercial Cc1. A maior população de lactobacilos termófilos nos queijos experimentais...The Parmesan is a typical Italian Cheese and has peculiar characteristics such as low moisture level, a granular texture and spicy flavor. Its processing involves long period of ripening and during this stage there are many biochemical reactions produced by enzymes from the raw milk, rennet and those produced by bacteria, resulting in changes in texture and taste of this product. The spontaneous autolysis of thermophilous microorganisms, such as Lactobacillus helveticus, is an important technological feature for the choice of cultures with potential application in the production of hard Cheeses, such as Parmesan. The objective of this study was to assess the autolytic performance of cultures of autochthonous Lb. helveticus, previously isolated from natural whey starter during the ripening of Parmesan Cheese. Autochthonous cultures of Lb. helveticus, E5 with high autolytic profile and A and D1 with intermediary autolytic profile were used. The commercial culture Cc1 (Lh-B02, Chr. Hansen) with high autolitic profile was used as control. The activity of in situ intracellular enzymes LDH and PepX, and the cell viability after 48 hours of growth were determined. Every month during the 180 days of ripening the population of thermophilous lactobacilli, the activity of enzymes LDH and PepX, the acidity, tyrosine, tryptophan contents and the index of ripening on Parmesan Cheese were determined. The highest release in vitro of the LDH and PepX enzymes was observed in the commercial culture Cc1 and autocthonous E5 and similar culture A and the commercial culture Cc1. The highest population of thermophilous lactobacilli in the experimental Cheeses was observed at the 30 days of ripening. In all Cheeses samples it was observed in the Cheeses produced with cultures with higher autolytic profile. There was a significant increase in acidity, tyrosine and tryptophan contents and IR in all samples... (Complete abstract click electronic access below
Hedda Hillmann - One of the best experts on this subject based on the ideXlab platform.
-
Quantitation of Key Tastants and Re-engineering the Taste of Parmesan Cheese
Journal of agricultural and food chemistry, 2016Co-Authors: Hedda Hillmann, Thomas HofmannAbstract:Targeted quantitation of 65 candidate taste compounds and ranking on the basis of dose-over-threshold (DoT) factors, followed by taste re-engineering and omission experiments in aqueous solution as well as in a Cheese-like model matrix, led to the identification of a total of 31 key tastants (amino acids, organic acids, fatty acids, biogenic amines, and minerals) with DoT factors ≥1.0 and a total of 15 subthreshold, but kokumi-enhancing, γ-glutamyl peptides in extraordinarily high concentrations of 20468 μmol/kg. Among the γ-glutamyl peptides, γ-Glu-Gly, γ-Glu-Ala, γ-Glu-Thr, γ-Glu-Asp, γ-Glu-Lys, γ-Glu-Glu, γ-Glu-Trp, γ-Glu-Gln, and γ-Glu-His have been identified for the first time in Parmesan Cheese. The excellent match of the sensory profile of the taste recombinants and the authentic Cheese demonstrated the identified taste compounds to be fully sufficient to create the characteristic taste profile of the Parmesan Cheese. This molecular blueprint of a Parmesan’s chemosensory signature might be a usefu...
-
formation of kokumi enhancing γ glutamyl dipeptides in Parmesan Cheese by means of γ glutamyltransferase activity and stable isotope double labeling studies
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Hedda Hillmann, Rudi F. Vogel, Jurgen Behr, Matthias A Ehrmann, Thomas HofmannAbstract:Recently, γ-glutamyl dipeptides (γ-GPs) were found to be responsible for the attractive kokumi flavor of Parmesan Cheese (PC). Quantitation of γ-GPs and their parent amino acids in 13-, 24-, and 30-month ripened PC samples by LC-MS/MS and stable isotope dilution analysis (SIDA), in-Cheese 13C-labeling studies, followed by analysis of the γ-glutamyl transferase (GGT) activity revealed γ-GPs to be generated most efficiently after 24 months of ripening by a GGT-catalyzed transfer of the γ-glutamyl moiety of l-glutamine onto various acceptor amino acids released upon casein proteolysis. Following the identification of milk as a potential GGT source in PC, the functionality of the milk’s GGT to generate the target γ-GPs was validated by stable isotope double-labeling (SIDL) experiments. Therefore, raw and heat-treated milk samples were incubated with l-glutamine-[U-13C] and acceptor amino acids (X) and the hetero- (γ-Glu-[13C5]-X) and homotranspeptidation products (γ-Glu-Gln-[13C10]) were quantitated by LC-MS/...
-
Formation of Kokumi-Enhancing γ‑Glutamyl Dipeptides in Parmesan Cheese by Means of γ‑Glutamyltransferase Activity and Stable Isotope Double-Labeling Studies
2016Co-Authors: Hedda Hillmann, Jürgen Behr, Matthias A. Ehrmann, Rudi F. Vogel, Thomas HofmannAbstract:Recently, γ-glutamyl dipeptides (γ-GPs) were found to be responsible for the attractive kokumi flavor of Parmesan Cheese (PC). Quantitation of γ-GPs and their parent amino acids in 13-, 24-, and 30-month ripened PC samples by LC-MS/MS and stable isotope dilution analysis (SIDA), in-Cheese 13C-labeling studies, followed by analysis of the γ-glutamyl transferase (GGT) activity revealed γ-GPs to be generated most efficiently after 24 months of ripening by a GGT-catalyzed transfer of the γ-glutamyl moiety of l-glutamine onto various acceptor amino acids released upon casein proteolysis. Following the identification of milk as a potential GGT source in PC, the functionality of the milk’s GGT to generate the target γ-GPs was validated by stable isotope double-labeling (SIDL) experiments. Therefore, raw and heat-treated milk samples were incubated with l-glutamine-[U-13C] and acceptor amino acids (X) and the hetero- (γ-Glu-[13C5]-X) and homotranspeptidation products (γ-Glu-Gln-[13C10]) were quantitated by LC-MS/MS-SIDA using γ-Glu-Ala-[13C3] as the internal standard. High GGT activity to generate the γ-GPs and preference for l-phenylalanine and l-methionine as acceptor amino acids were found in raw milk and milk samples heat-treated for 10 min up to a maximum of 65 °C. In comparison, GGT activity and SIDL studies performed with inoculated Lactobacillus strains, including Lactobacillus harbinensis and Lactobacillus casei identified in PC by means of 16S rRNA gene sequencing, did not show any significant GGT activity and unequivocally demonstrated unpasteurized cow’s milk, rather than microorganisms, as a key factor in γ-glutamyl dipeptide generation in Parmesan Cheese