Christophe Flahaut - Academia.edu (original) (raw)
Papers by Christophe Flahaut
a<p>Identification score: the relevance of protein identities was judged according to the p... more a<p>Identification score: the relevance of protein identities was judged according to the probability-based molecular weight search score <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048428#pone.0048428-Perkins1" target="_blank">[33]</a> (calculated with p<0.05)). The significance threshold of ions scores corresponds to the value of 31.</p>b<p>Protein identified in brain capillary endothelial cells displaying limited BBB (Lim. BBB) or re-induced BBB (Re-ind. BBB) functions.</p
Aquaculture, 2021
One of the major threats to the seabass (Dicentrarchus labrax) aquaculture sector is the developm... more One of the major threats to the seabass (Dicentrarchus labrax) aquaculture sector is the development of vibriosis, a disease caused mainly by bacteria from the family Vibrionaceae, especially Vibrio harveyi. This disease can result in important economic losses or severe public health problems. Furthermore, bacteria can form biofilms on the walls of aquaculture tanks, leading to the persistence of potentially pathogenic bacteria on fish farms. Given the relationship between abundance in the surrounding environment and prevalence in fish, monitoring the presence of V. harveyi in rearing water and biofilms over time may help better understand the dynamics of the pathogen and factors that increase the risk of vibriosis outbreaks. In this study, the dynamics and spatial patterns of cultivable Vibrionaceae and V. harveyi in water and biofilms from rearing tanks and in the cold-and hot-water inlets supplying the farm were monitored for 7 months. Several potential seabass pathogens were isolated: Photobacterium damselae , Vibrio alginolyticus , V. harveyi , Vibrio owensii and Vibrio rotiferianus. However, V. harveyi remained the most problematic pathogen. Its relatively constant presence in water and biofilm samples throughout the sampling campaign represents a risk for vibriosis outbreaks. Moreover, the correlation between water temperature and the abundance of V. harveyi suggests that the risk fluctuates throughout the year. Obtaining qualitative data regarding the relative diversity of viable culturable Vibrionaceae and quantitative data on the abundance of V. harveyi over time in a seabass aquaculture facility is the essential first step for designing new solutions to manage vibriosis.
International Journal of Molecular Sciences
Dipeptidyl-peptidase IV (DPP-IV) plays an essential role in glucose metabolism by inactivating in... more Dipeptidyl-peptidase IV (DPP-IV) plays an essential role in glucose metabolism by inactivating incretins. In this context, food-protein-derived DPP-IV inhibitors are promising glycemic regulators which may act by preventing the onset of type 2 diabetes in personalized nutrition. In this study, the DPP-IV-inhibitory potential of seven proteins from diverse origins was compared for the first time in vitro and in vivo in rat plasma after the intestinal barrier (IB) passage of the indigested proteins. The DPP-IV-inhibitory potentials of bovine hemoglobin, caseins, chicken ovalbumin, fish gelatin, and pea proteins were determined in rat plasma thirty minutes after oral administration. In parallel, these proteins, together with bovine whey and gluten proteins, were digested using the harmonized INFOGEST protocol adapted for proteins. The DPP-IV half-maximal inhibitory concentration (IC50) was determined in situ using Caco-2 cells. The DPP-IV-inhibitory activity was also measured after IB ...
Frontiers in Bioengineering and Biotechnology, 2020
Production of bioactive peptides (BAPs) by Lactobacillus species is a cost-effective approach com... more Production of bioactive peptides (BAPs) by Lactobacillus species is a cost-effective approach compared to the use of purified enzymes. In this study, proteolytic Lactobacillus helveticus strains were used for milk fermentation to produce BAPs capable of inhibiting angiotensin converting enzyme (ACE). Fermented milks were produced in bioreactors using batch mode, and the resulting products showed significant ACE-inhibitory activities. However, the benefits of fermentation in terms of peptide composition and ACE-inhibitory activity were noticeably reduced when the samples (fermented milks and non-fermented controls) were subject to simulated gastrointestinal digestion (GID). Introducing an ultrafiltration step after fermentation allowed to prevent this effect of GID and restored the effect of fermentation. Furthermore, an integrated continuous process for peptide production was developed which led to a 3 fold increased peptide productivity compared to batch production. Using a membran...
Food Quality and Preference
Abstract Consumers’ food choices are affected by various factors whose study is of interest for f... more Abstract Consumers’ food choices are affected by various factors whose study is of interest for food industry. This paper aims to investigate the influence of familiarity on the expectation and liking of Maroilles cheese among consumers familiar and unfamiliar with the product in France. It specifically focuses on two elements of the familiarity: consumption frequency and knowledge and studies their interactions. A hedonic test on Maroilles cheeses was carried out with 305 consumers from Lille city (familiar with Maroilles cheese) and from Angers city (unfamiliar). The test included three conditions: blind (tasting without any information), expected (no tasting, presentation of the photo of the packaging) and informed conditions (tasting + presentation of the photo of the packaging). A questionnaire was also administrated to assess their socio-demographic information, theoretical knowledge and consumption habits related to Maroilles cheeses. Results show that, as expected, Lille consumers eat more Maroilles and show higher liking scores for this cheese than Angers consumers do. Lille consumers outperform Angers consumers on their knowledge score and an interaction between the levels of knowledge and exposure is observed: Lille consumers with the higher level of knowledge have higher expectations of Maroilles cheese than Lille consumers with the lower level of knowledge. This effect is not observed with Angers consumers. Moreover, consumers familiar with Maroilles based their hedonic judgment mainly on intrinsic cues (tasting) whereas consumers unfamiliar with Maroilles are more influenced by extrinsic cues (packaging). Familiarity affects how consumers use available information to form product quality judgement.
Foods
Protein hydrolysates are, in general, mixtures of amino acids and small peptides able to supply t... more Protein hydrolysates are, in general, mixtures of amino acids and small peptides able to supply the body with the constituent elements of proteins in a directly assimilable form. They are therefore characterised as products with high nutritional value. However, hydrolysed proteins display an unpleasant bitter taste and possible off-flavours which limit the field of their nutrition applications. The successful identification and characterisation of bitter protein hydrolysates and, more precisely, the peptides responsible for this unpleasant taste are essential for nutritional research. Due to the large number of peptides generated during hydrolysis, there is an urgent need to develop methods in order to rapidly characterise the bitterness of protein hydrolysates. In this article, two enzymatic hydrolysis kinetics of micellar milk caseins were performed for 9 h. For both kinetics, the optimal time to obtain a hydrolysate with appreciable organoleptic qualities is 5 h. Then, the influe...
Membranes
Bovine cruor, a slaughterhouse waste, was mainly composed of hemoglobin, a protein rich in antiba... more Bovine cruor, a slaughterhouse waste, was mainly composed of hemoglobin, a protein rich in antibacterial and antioxidant peptides after its hydrolysis. In the current context of food safety, such bioactive peptides derived from enzymatic hydrolysis of hemoglobin represent potential promising preservatives for the food sector. In this work, the hemoglobin hydrolysis to produce bioactive peptides was performed in a regulated pH medium without the use of chemical solvents and by an eco-efficient process: electrodialysis with bipolar membrane (EDBM). Bipolar/monopolar (anionic or cationic) configuration using the H+ and OH− generated by the bipolar membranes to regulate the pH was investigated. The aim of this study was to present and identify the bioactive peptides produced by EDBM in comparison with conventional hydrolysis and to identify their biological activity. The use of the EDBM for the enzymatic hydrolysis of hemoglobin has allowed for the production and identification of 17 bi...
Foods
The identification of phosphopeptides is currently a challenge when they are part of a complex ma... more The identification of phosphopeptides is currently a challenge when they are part of a complex matrix of peptides, such as a milk protein enzymatic hydrolysate. This challenge increases with both the number of phosphorylation sites on the phosphopeptides and their amino acid length. Here, this paper reports a four-phase strategy from an enzymatic casein hydrolysate before a mass spectrometry analysis in order to enhance the identification of phosphopeptides and phosphosites: (i) the control protein hydrolysate, (ii) a two-step enzymatic dephosphorylation of the latter, allowing for the almost total dephosphorylation of peptides, (iii) a one-step enzymatic dephosphorylation, allowing for the partial dephosphorylation of the peptides and (iv) an additional endoGluC enzymatic hydrolysis, allowing for the cleavage of long-size peptides into shorter ones. The reverse-phase high-pressure liquid chromatography–tandem mass spectrometry (RP-HPLC-MS/MS) analyses of hydrolysates that underwent...
Frontiers in Plant Science
This study aimed to examine the ability of ulvan, a water-soluble polysaccharide from the green s... more This study aimed to examine the ability of ulvan, a water-soluble polysaccharide from the green seaweed Ulva fasciata, to provide protection and induce resistance in wheat against the hemibiotrophic fungus Zymoseptoria tritici. Matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) analysis indicated that ulvan is mainly composed of unsaturated monosaccharides (rhamnose, rhamnose-3-sulfate, and xylose) and numerous uronic acid residues. In the greenhouse, foliar application of ulvan at 10 mg.ml–1 2 days before fungal inoculation reduced disease severity and pycnidium density by 45 and 50%, respectively. Ulvan did not exhibit any direct antifungal activity toward Z. tritici, neither in vitro nor in planta. However, ulvan treatment significantly reduced substomatal colonization and pycnidium formation within the mesophyll of treated leaves. Molecular assays revealed that ulvan spraying elicits, but does not prime, the expression of genes involved i...
Membranes
Neokyotorphin (α137-141) is recognized as an antimicrobial peptide and a natural meat preservativ... more Neokyotorphin (α137-141) is recognized as an antimicrobial peptide and a natural meat preservative. It is produced by conventional enzymatic hydrolysis of bovine hemoglobin, a major component of cruor, a by-product of slaughterhouses. However, during conventional hydrolysis, chemical agents are necessary to adjust and regulate the pH of the protein solution and the mineral salt content of the final hydrolysate is consequently high. To produce this peptide of interest without chemical agents and with a low salt concentration, electrodialysis with bipolar membrane (EDBM), an electromembrane process recognized as a green process, with two different membrane configurations (cationic (MCP) and anionic (AEM) membranes) was investigated. Hydrolysis in EDBM showed the same enzymatic mechanism, “Zipper”, and allowed the generation of α137-141 in the same concentration as observed in conventional hydrolysis (control). EDBM-MCP allowed the production of hydrolysates containing a low concentrat...
Frontiers in Microbiology
Molecules
Like their owners, dogs and cats are more and more affected by overweight and obesity-related pro... more Like their owners, dogs and cats are more and more affected by overweight and obesity-related problems and interest in functional pet foods is growing sharply. Through numerous studies, fish protein hydrolysates have proved their worth to prevent and manage obesity-related comorbidities like diabetes. In this work, a human in vitro static simulated gastrointestinal digestion model was adapted to the dog which allowed us to demonstrate the promising effects of a tilapia byproduct hydrolysate on the regulation of food intake and glucose metabolism. Promising effects on intestinal hormones secretion and dipeptidyl peptidase IV (DPP-IV) inhibitory activity were evidenced. We identify new bioactive peptides able to stimulate cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1) secretions, and to inhibit the DPP-IV activity after a transport study through a Caco-2 cell monolayer.
Foods
The goal of this study was to determine the impact of industrial processes on the digestion of si... more The goal of this study was to determine the impact of industrial processes on the digestion of six milk protein matrices using the harmonized INFOGEST in vitro static digestion protocol. First, this method was optimized to simple protein matrices using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) to compare the intestinal protein hydrolysis obtained with increasing quantities of pancreatin. Similar results were achieved with the originally required pancreatin amount (trypsin activity of 100 U.mL−1) and with a quantity of pancreatin equivalent to a trypsin activity of 27.3 U.mL−1, which was thus used to perform the in vitro digestion of the milk matrices. Molecular weight profiles, peptide heterogeneity from LC-MS/MS data, calcium, free amino acid, and peptide concentrations were determined in the gastric and intestinal phases to compare the milk protein digests. Results showed that the industrial process affected not on...
Foods
Enzymatic hydrolysis of food proteins generally changes the techno-functional, nutritional, and o... more Enzymatic hydrolysis of food proteins generally changes the techno-functional, nutritional, and organoleptic properties of hydrolyzed proteins. As a result, protein hydrolysates have an important interest in the food industries. However, they tend to be characterized by a bitter taste and some off-flavors, which limit their use in the food industry. These tastes and aromas come from peptides, amino acids, and volatile compounds generated during hydrolysis. In this article, sixteen more or less bitter enzymatic hydrolysates produced from a milk protein liquid fraction enriched in micellar caseins using commercially available, food-grade proteases were subjected to a sensory analysis using a trained and validated sensory panel combined to a peptidomics approach based on the peptide characterization by reverse-phase high-performance liquid chromatography, high-resolution mass spectrometry, and bioinformatics software. The comparison between the sensory characteristics and the principal...
Food Research International
Biotechnology and Applied Biochemistry
Molecules
Pseudomonas species are metabolically robust, with capacity to produce secondary metabolites incl... more Pseudomonas species are metabolically robust, with capacity to produce secondary metabolites including cyclic lipopeptides (CLPs). Herein we conducted a chemical analysis of a crude CLP extract from the cocoyam rhizosphere-derived biocontrol strain Pseudomonas sp. COW3. We performed in silico analyses on its whole genome, and conducted in vitro antagonistic assay using the strain and purified CLPs. Via LC-MS and NMR, we elucidated the structures of four novel members of the bananamide group, named bananamides D-G. Besides variability in fatty acid length, bananamides D-G differ from previously described bananamides A-C and MD-0066 by the presence of a serine and aspartic acid at position 6 and 2, respectively. In addition, bananamide G has valine instead of isoleucine at position 8. Kendrick mass defect (KMD) allowed the assignment of molecular formulae to bananamides D and E. We unraveled a non-ribosomal peptide synthetase cluster banA, banB and banC which encodes the novel bananam...
Journal of The American Society for Mass Spectrometry
The identificati on of k nown (dereplication) or unknown nonribosomal peptides (NRPs) produced by... more The identificati on of k nown (dereplication) or unknown nonribosomal peptides (NRPs) produced by microorganisms is a time consuming, expensive, and challenging task where mass spectrometry and nuclear magnetic resonance play a key role. The first step of the identification process always involves the establishment of a molecular formula. Unfortunately, the number of potential molecular formulae increases significantly with higher molecular masses and the lower precision of their measurements. In the present article, we demonstrate that molecular formula assignment can be achieved by a combined approach using the regular Kendrick mass defect (RKMD) and NORINE, the reference curated database of NRPs. We observed that irrespective of the molecular formula, the addition and subtraction of a given atom or atom group always leads to the same RKMD variation and nominal Kendrick mass (NKM). Graphically, these variations translated into a vector mesh can be used to connect an unknown molecule to a known NRP of the NORINE database and establish its molecular formula. We explain and illustrate this concept through the high-resolution mass spectrometry analysis of a commercially available mixture composed of four surfactins. The Kendrick approach enriched with the NORINE database content is a fast, useful, and easy-to-use tool for molecular mass assignment of known and unknown NRP structures.
a<p>Identification score: the relevance of protein identities was judged according to the p... more a<p>Identification score: the relevance of protein identities was judged according to the probability-based molecular weight search score <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048428#pone.0048428-Perkins1" target="_blank">[33]</a> (calculated with p<0.05)). The significance threshold of ions scores corresponds to the value of 31.</p>b<p>Protein identified in brain capillary endothelial cells displaying limited BBB (Lim. BBB) or re-induced BBB (Re-ind. BBB) functions.</p
Aquaculture, 2021
One of the major threats to the seabass (Dicentrarchus labrax) aquaculture sector is the developm... more One of the major threats to the seabass (Dicentrarchus labrax) aquaculture sector is the development of vibriosis, a disease caused mainly by bacteria from the family Vibrionaceae, especially Vibrio harveyi. This disease can result in important economic losses or severe public health problems. Furthermore, bacteria can form biofilms on the walls of aquaculture tanks, leading to the persistence of potentially pathogenic bacteria on fish farms. Given the relationship between abundance in the surrounding environment and prevalence in fish, monitoring the presence of V. harveyi in rearing water and biofilms over time may help better understand the dynamics of the pathogen and factors that increase the risk of vibriosis outbreaks. In this study, the dynamics and spatial patterns of cultivable Vibrionaceae and V. harveyi in water and biofilms from rearing tanks and in the cold-and hot-water inlets supplying the farm were monitored for 7 months. Several potential seabass pathogens were isolated: Photobacterium damselae , Vibrio alginolyticus , V. harveyi , Vibrio owensii and Vibrio rotiferianus. However, V. harveyi remained the most problematic pathogen. Its relatively constant presence in water and biofilm samples throughout the sampling campaign represents a risk for vibriosis outbreaks. Moreover, the correlation between water temperature and the abundance of V. harveyi suggests that the risk fluctuates throughout the year. Obtaining qualitative data regarding the relative diversity of viable culturable Vibrionaceae and quantitative data on the abundance of V. harveyi over time in a seabass aquaculture facility is the essential first step for designing new solutions to manage vibriosis.
International Journal of Molecular Sciences
Dipeptidyl-peptidase IV (DPP-IV) plays an essential role in glucose metabolism by inactivating in... more Dipeptidyl-peptidase IV (DPP-IV) plays an essential role in glucose metabolism by inactivating incretins. In this context, food-protein-derived DPP-IV inhibitors are promising glycemic regulators which may act by preventing the onset of type 2 diabetes in personalized nutrition. In this study, the DPP-IV-inhibitory potential of seven proteins from diverse origins was compared for the first time in vitro and in vivo in rat plasma after the intestinal barrier (IB) passage of the indigested proteins. The DPP-IV-inhibitory potentials of bovine hemoglobin, caseins, chicken ovalbumin, fish gelatin, and pea proteins were determined in rat plasma thirty minutes after oral administration. In parallel, these proteins, together with bovine whey and gluten proteins, were digested using the harmonized INFOGEST protocol adapted for proteins. The DPP-IV half-maximal inhibitory concentration (IC50) was determined in situ using Caco-2 cells. The DPP-IV-inhibitory activity was also measured after IB ...
Frontiers in Bioengineering and Biotechnology, 2020
Production of bioactive peptides (BAPs) by Lactobacillus species is a cost-effective approach com... more Production of bioactive peptides (BAPs) by Lactobacillus species is a cost-effective approach compared to the use of purified enzymes. In this study, proteolytic Lactobacillus helveticus strains were used for milk fermentation to produce BAPs capable of inhibiting angiotensin converting enzyme (ACE). Fermented milks were produced in bioreactors using batch mode, and the resulting products showed significant ACE-inhibitory activities. However, the benefits of fermentation in terms of peptide composition and ACE-inhibitory activity were noticeably reduced when the samples (fermented milks and non-fermented controls) were subject to simulated gastrointestinal digestion (GID). Introducing an ultrafiltration step after fermentation allowed to prevent this effect of GID and restored the effect of fermentation. Furthermore, an integrated continuous process for peptide production was developed which led to a 3 fold increased peptide productivity compared to batch production. Using a membran...
Food Quality and Preference
Abstract Consumers’ food choices are affected by various factors whose study is of interest for f... more Abstract Consumers’ food choices are affected by various factors whose study is of interest for food industry. This paper aims to investigate the influence of familiarity on the expectation and liking of Maroilles cheese among consumers familiar and unfamiliar with the product in France. It specifically focuses on two elements of the familiarity: consumption frequency and knowledge and studies their interactions. A hedonic test on Maroilles cheeses was carried out with 305 consumers from Lille city (familiar with Maroilles cheese) and from Angers city (unfamiliar). The test included three conditions: blind (tasting without any information), expected (no tasting, presentation of the photo of the packaging) and informed conditions (tasting + presentation of the photo of the packaging). A questionnaire was also administrated to assess their socio-demographic information, theoretical knowledge and consumption habits related to Maroilles cheeses. Results show that, as expected, Lille consumers eat more Maroilles and show higher liking scores for this cheese than Angers consumers do. Lille consumers outperform Angers consumers on their knowledge score and an interaction between the levels of knowledge and exposure is observed: Lille consumers with the higher level of knowledge have higher expectations of Maroilles cheese than Lille consumers with the lower level of knowledge. This effect is not observed with Angers consumers. Moreover, consumers familiar with Maroilles based their hedonic judgment mainly on intrinsic cues (tasting) whereas consumers unfamiliar with Maroilles are more influenced by extrinsic cues (packaging). Familiarity affects how consumers use available information to form product quality judgement.
Foods
Protein hydrolysates are, in general, mixtures of amino acids and small peptides able to supply t... more Protein hydrolysates are, in general, mixtures of amino acids and small peptides able to supply the body with the constituent elements of proteins in a directly assimilable form. They are therefore characterised as products with high nutritional value. However, hydrolysed proteins display an unpleasant bitter taste and possible off-flavours which limit the field of their nutrition applications. The successful identification and characterisation of bitter protein hydrolysates and, more precisely, the peptides responsible for this unpleasant taste are essential for nutritional research. Due to the large number of peptides generated during hydrolysis, there is an urgent need to develop methods in order to rapidly characterise the bitterness of protein hydrolysates. In this article, two enzymatic hydrolysis kinetics of micellar milk caseins were performed for 9 h. For both kinetics, the optimal time to obtain a hydrolysate with appreciable organoleptic qualities is 5 h. Then, the influe...
Membranes
Bovine cruor, a slaughterhouse waste, was mainly composed of hemoglobin, a protein rich in antiba... more Bovine cruor, a slaughterhouse waste, was mainly composed of hemoglobin, a protein rich in antibacterial and antioxidant peptides after its hydrolysis. In the current context of food safety, such bioactive peptides derived from enzymatic hydrolysis of hemoglobin represent potential promising preservatives for the food sector. In this work, the hemoglobin hydrolysis to produce bioactive peptides was performed in a regulated pH medium without the use of chemical solvents and by an eco-efficient process: electrodialysis with bipolar membrane (EDBM). Bipolar/monopolar (anionic or cationic) configuration using the H+ and OH− generated by the bipolar membranes to regulate the pH was investigated. The aim of this study was to present and identify the bioactive peptides produced by EDBM in comparison with conventional hydrolysis and to identify their biological activity. The use of the EDBM for the enzymatic hydrolysis of hemoglobin has allowed for the production and identification of 17 bi...
Foods
The identification of phosphopeptides is currently a challenge when they are part of a complex ma... more The identification of phosphopeptides is currently a challenge when they are part of a complex matrix of peptides, such as a milk protein enzymatic hydrolysate. This challenge increases with both the number of phosphorylation sites on the phosphopeptides and their amino acid length. Here, this paper reports a four-phase strategy from an enzymatic casein hydrolysate before a mass spectrometry analysis in order to enhance the identification of phosphopeptides and phosphosites: (i) the control protein hydrolysate, (ii) a two-step enzymatic dephosphorylation of the latter, allowing for the almost total dephosphorylation of peptides, (iii) a one-step enzymatic dephosphorylation, allowing for the partial dephosphorylation of the peptides and (iv) an additional endoGluC enzymatic hydrolysis, allowing for the cleavage of long-size peptides into shorter ones. The reverse-phase high-pressure liquid chromatography–tandem mass spectrometry (RP-HPLC-MS/MS) analyses of hydrolysates that underwent...
Frontiers in Plant Science
This study aimed to examine the ability of ulvan, a water-soluble polysaccharide from the green s... more This study aimed to examine the ability of ulvan, a water-soluble polysaccharide from the green seaweed Ulva fasciata, to provide protection and induce resistance in wheat against the hemibiotrophic fungus Zymoseptoria tritici. Matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) analysis indicated that ulvan is mainly composed of unsaturated monosaccharides (rhamnose, rhamnose-3-sulfate, and xylose) and numerous uronic acid residues. In the greenhouse, foliar application of ulvan at 10 mg.ml–1 2 days before fungal inoculation reduced disease severity and pycnidium density by 45 and 50%, respectively. Ulvan did not exhibit any direct antifungal activity toward Z. tritici, neither in vitro nor in planta. However, ulvan treatment significantly reduced substomatal colonization and pycnidium formation within the mesophyll of treated leaves. Molecular assays revealed that ulvan spraying elicits, but does not prime, the expression of genes involved i...
Membranes
Neokyotorphin (α137-141) is recognized as an antimicrobial peptide and a natural meat preservativ... more Neokyotorphin (α137-141) is recognized as an antimicrobial peptide and a natural meat preservative. It is produced by conventional enzymatic hydrolysis of bovine hemoglobin, a major component of cruor, a by-product of slaughterhouses. However, during conventional hydrolysis, chemical agents are necessary to adjust and regulate the pH of the protein solution and the mineral salt content of the final hydrolysate is consequently high. To produce this peptide of interest without chemical agents and with a low salt concentration, electrodialysis with bipolar membrane (EDBM), an electromembrane process recognized as a green process, with two different membrane configurations (cationic (MCP) and anionic (AEM) membranes) was investigated. Hydrolysis in EDBM showed the same enzymatic mechanism, “Zipper”, and allowed the generation of α137-141 in the same concentration as observed in conventional hydrolysis (control). EDBM-MCP allowed the production of hydrolysates containing a low concentrat...
Frontiers in Microbiology
Molecules
Like their owners, dogs and cats are more and more affected by overweight and obesity-related pro... more Like their owners, dogs and cats are more and more affected by overweight and obesity-related problems and interest in functional pet foods is growing sharply. Through numerous studies, fish protein hydrolysates have proved their worth to prevent and manage obesity-related comorbidities like diabetes. In this work, a human in vitro static simulated gastrointestinal digestion model was adapted to the dog which allowed us to demonstrate the promising effects of a tilapia byproduct hydrolysate on the regulation of food intake and glucose metabolism. Promising effects on intestinal hormones secretion and dipeptidyl peptidase IV (DPP-IV) inhibitory activity were evidenced. We identify new bioactive peptides able to stimulate cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1) secretions, and to inhibit the DPP-IV activity after a transport study through a Caco-2 cell monolayer.
Foods
The goal of this study was to determine the impact of industrial processes on the digestion of si... more The goal of this study was to determine the impact of industrial processes on the digestion of six milk protein matrices using the harmonized INFOGEST in vitro static digestion protocol. First, this method was optimized to simple protein matrices using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) to compare the intestinal protein hydrolysis obtained with increasing quantities of pancreatin. Similar results were achieved with the originally required pancreatin amount (trypsin activity of 100 U.mL−1) and with a quantity of pancreatin equivalent to a trypsin activity of 27.3 U.mL−1, which was thus used to perform the in vitro digestion of the milk matrices. Molecular weight profiles, peptide heterogeneity from LC-MS/MS data, calcium, free amino acid, and peptide concentrations were determined in the gastric and intestinal phases to compare the milk protein digests. Results showed that the industrial process affected not on...
Foods
Enzymatic hydrolysis of food proteins generally changes the techno-functional, nutritional, and o... more Enzymatic hydrolysis of food proteins generally changes the techno-functional, nutritional, and organoleptic properties of hydrolyzed proteins. As a result, protein hydrolysates have an important interest in the food industries. However, they tend to be characterized by a bitter taste and some off-flavors, which limit their use in the food industry. These tastes and aromas come from peptides, amino acids, and volatile compounds generated during hydrolysis. In this article, sixteen more or less bitter enzymatic hydrolysates produced from a milk protein liquid fraction enriched in micellar caseins using commercially available, food-grade proteases were subjected to a sensory analysis using a trained and validated sensory panel combined to a peptidomics approach based on the peptide characterization by reverse-phase high-performance liquid chromatography, high-resolution mass spectrometry, and bioinformatics software. The comparison between the sensory characteristics and the principal...
Food Research International
Biotechnology and Applied Biochemistry
Molecules
Pseudomonas species are metabolically robust, with capacity to produce secondary metabolites incl... more Pseudomonas species are metabolically robust, with capacity to produce secondary metabolites including cyclic lipopeptides (CLPs). Herein we conducted a chemical analysis of a crude CLP extract from the cocoyam rhizosphere-derived biocontrol strain Pseudomonas sp. COW3. We performed in silico analyses on its whole genome, and conducted in vitro antagonistic assay using the strain and purified CLPs. Via LC-MS and NMR, we elucidated the structures of four novel members of the bananamide group, named bananamides D-G. Besides variability in fatty acid length, bananamides D-G differ from previously described bananamides A-C and MD-0066 by the presence of a serine and aspartic acid at position 6 and 2, respectively. In addition, bananamide G has valine instead of isoleucine at position 8. Kendrick mass defect (KMD) allowed the assignment of molecular formulae to bananamides D and E. We unraveled a non-ribosomal peptide synthetase cluster banA, banB and banC which encodes the novel bananam...
Journal of The American Society for Mass Spectrometry
The identificati on of k nown (dereplication) or unknown nonribosomal peptides (NRPs) produced by... more The identificati on of k nown (dereplication) or unknown nonribosomal peptides (NRPs) produced by microorganisms is a time consuming, expensive, and challenging task where mass spectrometry and nuclear magnetic resonance play a key role. The first step of the identification process always involves the establishment of a molecular formula. Unfortunately, the number of potential molecular formulae increases significantly with higher molecular masses and the lower precision of their measurements. In the present article, we demonstrate that molecular formula assignment can be achieved by a combined approach using the regular Kendrick mass defect (RKMD) and NORINE, the reference curated database of NRPs. We observed that irrespective of the molecular formula, the addition and subtraction of a given atom or atom group always leads to the same RKMD variation and nominal Kendrick mass (NKM). Graphically, these variations translated into a vector mesh can be used to connect an unknown molecule to a known NRP of the NORINE database and establish its molecular formula. We explain and illustrate this concept through the high-resolution mass spectrometry analysis of a commercially available mixture composed of four surfactins. The Kendrick approach enriched with the NORINE database content is a fast, useful, and easy-to-use tool for molecular mass assignment of known and unknown NRP structures.