Emulsification en continu avec un microsystème en vue de l'encapsulation d'antioxydants

National audienceRESUME Cette étude porte sur une problématique qui intéresse le secteur des compléments alimentaires et celui de la santé. Des chercheurs ont récemment développé un protocole [1] permettant une extraction et une « encapsulation » par émulsification d'antioxydants naturels (astaxanthine,  carotènes ou lycopènes), pour la plupart issus de microalgues, basées sur l'emploi de molécules plus respectueuses de l'environnement et peu couteuses. Ce protocole est à ce stade réalisé manuellement, en réacteur batch et met en jeu des petits volumes. Il serait intéressant de le transposer vers un procédé fonctionnant en continu permettant de traiter des volumes plus importants, de manière plus reproductible et en limitant le contact de la phase lipidique avec l'oxygène. L'idée proposée ici est de mettre en oeuvre un micromélangeur [2] développé par les laboratoires GEPEA et LTeN afin d'étudier son potentiel vis-à-vis de ce type d'application. Ce type de micromélangeur (Figure 1), basé sur un mélange intime des fluides dans un volume très réduit (< 1mL) et avec un temps de séjour très faible (de l'ordre de la milliseconde), peut être une solution intéressante au regard des contraintes liées à cette application. Les débits maximaux atteints par ce dispositif sont de l'ordre de 600 mL/min ce qui est compatible avec une production à pteite ou moyenne échelle. D'autre part, s'agissant de la perspective de l' « usine du futur », la mise en oeuvre de systèmes intensifiés s'inscrit dans une dynamique de développement de procédés miniaturisés et globalement plus économes en énergie. Cette étude se concentre dans un premier temps sur des tests de formulation et d'émusification à l'échelle paillasse avec un système fonctionnant en batch, de type rotor-stator, en faisant varier divers paramètres tels que la vitesse et le temps de rotation du rotor, les proportions des deux phases et la composition de celles-ci. Cette première phase de l'étude permet d'affiner le choix de formulations d'émulsions de type huile dans eau offrant une bonne stabilité. Des essais sont ensuite menés avec le micromélangeur sur les formulations les plus intéressantes vis-à-vis de l'application visée. Les émulsions ainsi obtenues avec les deux systèmes sont alors comparées en termes de distribution granulométrique et de stabilité au cours du temps. Dans un dernier temps, l'étude s'intéresse à l'incorporation de  carotènes dans la formulation avec en particulier l'évaluation de l'efficacité de rétention des  carotènes dans la phase lipidique et l'étude de la stabilité chimique des émulsions obtenues. MOTS-CLES DU THEME Procédés émergents, Microprocédés, Microfluidique. MOTS-CLES LIBRES Emulsion, Fractionnement, procédé continu, antioxydan

Intérêt de l’utilisation de l’huile essentielle du Thymus Capitatus en élevage bovin laitier et impact sur la qualité du lait

Bovine mastitis is a major concern in cattle farming, and it can be caused by contagious or environmental pathogens. The costs associated with mastitis are significant. The current primary treatment is the use of antibiotics whose excessive use contributes to the development of antimicrobial resistance, posing a serious threat to public health. New alternatives, such as the use of essential oils (EOs), are needed to limit antibiotic therapy. This study aims to test the effectiveness of EOs on mastitis and evaluate their effects on milk quality. In vitro testing on human cells has shown that several EOs from Mediterranean plants have effective anti-inflammatory activities. Specifically, Thymus capitatus essential oil (TCEO)and its major component, carvacrol, are able to reduce inflammation in peripheral blood mononuclear cells (PBMC) isolated from cow blood. Their antibacterial properties are also demonstrated on Staphylococcus aureus and Escherichia coli. The antibacterial activity of TCEO is significantly enhanced by nano-emulsion, unlike that of carvacrol. In vivo tests, through topical application of 10% TCEO, are less conclusive, with no demonstrated improvement of mastitis. However, milk quality and microbiota remain preserved. Considering these results, further studies are needed to optimize EOs-based treatment for mastitis and to evaluate new application methods on dairy cows.La mammite bovine est une préoccupation majeure dans les élevages bovins. Elle est causée par des agents pathogènes contagieux ou environnementaux. Les coûts économiques liés aux mammites sont importants. Le traitement primaire reste l’usage des antibiotiques dont l'utilisation excessive contribue au développement de la résistance aux antimicrobiens, ce qui représente une menace sérieuse pour la santé publique. Des alternatives, comme l'utilisation d'huiles essentielles (HEs), sont nécessaires pour limiter l'antibiothérapie. Cette thèse a pour objectif de tester l’efficacité des HEs sur les mammites et d'évaluer leurs effets sur la qualité du lait. L’approche in vitro sur des cellules humaines a montré que plusieurs HEs de plantes méditerranéennes possèdent des activités anti-inflammatoires efficaces.L’HE de Thymus capitatus (HETC) et son principal composé, le carvacrol, sont également en mesure de diminuer l’inflammation sur des cellules mononuclées du sang périphérique (PBMC) isolées à partir de sang de vaches. Leurs effets antibactériens sont aussi démontrés sur Staphylococcus aureus et Escherichia coli. De plus, l’activité antibactérienne d’HETC est améliorée par nano-émulsion, contrairement à celle du carvacrol. Les tests in vivo, par application topique de 10% d'HETC, sont moins concluants. Aucune amélioration de la mammite n’a été démontrée. Néanmoins, la qualité du lait et son microbiote restent préservés. Tenant compte de ces résultats, d’autres études sont nécessaires pour optimiser le traitement à base d'HEs sur la mammite et évaluer de nouvelles voies d’application sur les vaches laitières

The benefits of using Thymus capitatus essential oil in dairy cattle farming and its impact on milk quality

La mammite bovine est une préoccupation majeure dans les élevages bovins. Elle est causée par des agents pathogènes contagieux ou environnementaux. Les coûts économiques liés aux mammites sont importants. Le traitement primaire reste l’usage des antibiotiques dont l'utilisation excessive contribue au développement de la résistance aux antimicrobiens, ce qui représente une menace sérieuse pour la santé publique. Des alternatives, comme l'utilisation d'huiles essentielles (HEs), sont nécessaires pour limiter l'antibiothérapie. Cette thèse a pour objectif de tester l’efficacité des HEs sur les mammites et d'évaluer leurs effets sur la qualité du lait. L’approche in vitro sur des cellules humaines a montré que plusieurs HEs de plantes méditerranéennes possèdent des activités anti-inflammatoires efficaces.L’HE de Thymus capitatus (HETC) et son principal composé, le carvacrol, sont également en mesure de diminuer l’inflammation sur des cellules mononuclées du sang périphérique (PBMC) isolées à partir de sang de vaches. Leurs effets antibactériens sont aussi démontrés sur Staphylococcus aureus et Escherichia coli. De plus, l’activité antibactérienne d’HETC est améliorée par nano-émulsion, contrairement à celle du carvacrol. Les tests in vivo, par application topique de 10% d'HETC, sont moins concluants. Aucune amélioration de la mammite n’a été démontrée. Néanmoins, la qualité du lait et son microbiote restent préservés. Tenant compte de ces résultats, d’autres études sont nécessaires pour optimiser le traitement à base d'HEs sur la mammite et évaluer de nouvelles voies d’application sur les vaches laitières.Bovine mastitis is a major concern in cattle farming, and it can be caused by contagious or environmental pathogens. The costs associated with mastitis are significant. The current primary treatment is the use of antibiotics whose excessive use contributes to the development of antimicrobial resistance, posing a serious threat to public health. New alternatives, such as the use of essential oils (EOs), are needed to limit antibiotic therapy. This study aims to test the effectiveness of EOs on mastitis and evaluate their effects on milk quality. In vitro testing on human cells has shown that several EOs from Mediterranean plants have effective anti-inflammatory activities. Specifically, Thymus capitatus essential oil (TCEO)and its major component, carvacrol, are able to reduce inflammation in peripheral blood mononuclear cells (PBMC) isolated from cow blood. Their antibacterial properties are also demonstrated on Staphylococcus aureus and Escherichia coli. The antibacterial activity of TCEO is significantly enhanced by nano-emulsion, unlike that of carvacrol. In vivo tests, through topical application of 10% TCEO, are less conclusive, with no demonstrated improvement of mastitis. However, milk quality and microbiota remain preserved. Considering these results, further studies are needed to optimize EOs-based treatment for mastitis and to evaluate new application methods on dairy cows

Sex Disparities in Resuscitation Quality Following Out of Hospital Cardiac Arrest

Background Women are known to be disadvantaged compared with men in the early links of the Chain of Survival, receiving fewer bystander interventions. We aimed to describe sex‐based disparities in emergency medical service resuscitation quality and processes of care for out‐of‐hospital cardiac arrest. Methods and Results We conducted a retrospective analysis of patients who were nontraumatic with out‐of‐hospital cardiac arrest aged ≥16 years where resuscitation was attempted between March 2019 and June 2023. We investigated 18 routinely captured performance metrics and performed adjusted logistic and quantile regression analyses to assess sex‐based differences in these metrics. During the study period, 10 161 patients with out‐of‐hospital cardiac arrest met the eligibility criteria, of whom 3216 (32%) were women. There were no clinically relevant sex‐based differences observed in regard to external cardiac compressions; however, women were 34% less likely to achieve a systolic blood pressure >100 mm Hg on arrival at the hospital (adjusted odds ratio [AOR], 0.66 [95% CI, 0.47–0.92]). Furthermore, women had a longer time to 12‐lead ECG acquisition after return of spontaneous circulation (median adjusted difference, 1.00 minute [95% CI, 0.38–1.62]) and 33% reduced odds of being transported to a 24‐hour percutaneous coronary intervention‐capable facility (AOR, 0.67 [95% CI, 0.49–0.91]). Resuscitation was also terminated sooner for women compared with men (median adjusted difference, −4.82 minutes [95% CI, −6.77 to −2.87]). Conclusions Although external cardiac compression quality did not vary by sex, significant sex‐based disparities were seen in emergency medical services processes of care following out‐of‐hospital cardiac arrest. Further investigation is required to elucidate the underlying causes of these differences and examine their influence on patient outcomes

Epidemiology of Community-Acquired Respiratory Tract Infections in Patients Admitted at the Emergency Departments

Objectives: Community-acquired respiratory infections (CARTIs) are responsible for serious morbidities worldwide. Identifying the aetiology can decrease the use of unnecessary antimicrobial therapy. In this study, we intend to determine the pathogenic agents responsible for respiratory infections in patients presenting to the emergency department of several Lebanese hospitals. Methods: A total of 100 patients presenting to the emergency departments of four Lebanese hospitals and identified as having CARTIs between September 2017 and September 2018 were recruited. Specimens of upper and lower respiratory tract samples were collected. Pathogens were detected by a multiplex polymerase chain reaction respiratory panel. Results: Of 100 specimens, 84 contained at least one pathogen. Many patients were detected with ≥2 pathogens. The total number of pathogens from these 84 patients was 163. Of these pathogens, 36 (22%) were human rhinovirus, 28 (17%) were Streptococcus pneumoniae, 16 (10%) were metapneumovirus, 16 (10%) were influenza A virus, and other pathogens were detected with lower percentages. As expected, the highest occurrence of pathogens was observed between December and March. Respiratory syncytial virus accounted for 2% of the cases and only correlated to paediatric patients. Conclusion: CARTI epidemiology is important and understudied in Lebanon. This study offers the first Lebanese data about CARTI pathogens. Viruses were the most common aetiologies of CARTIs. Thus, a different approach must be used for the empirical management of CARTI. Rapid testing might be useful in identifying patients who need antibiotic therapy

Essential Oils in Livestock: From Health to Food Quality

International audienceUsing plant essential oils (EOs) contributes to the growing number of natural plants’ applications in livestock. Scientific data supporting the efficacy of EOs as anti-inflammatory, antibacterial and antioxidant molecules accumulates over time; however, the cumulative evidence is not always sufficient. EOs antioxidant properties have been investigated mainly from human perspectives. Still, so far, our review is the first to combine the beneficial supporting properties of EOs in a One Health approach and as an animal product quality enhancer, opening new possibilities for their utilization in the livestock and nutrition sectors. We aim to compile the currently available data on the main anti-inflammatory effects of EOs, whether encapsulated or not, with a focus on mammary gland inflammation. We will also review the EOs’ antioxidant activities when given in the diet or as a food preservative to counteract oxidative stress. We emphasize EOs’ in vitro and in vivo ruminal microbiota and mechanisms of action to promote animal health and performance. Given the concept of DOHaD (Developmental Origin of Health and Diseases), supplementing animals with EOs in early life opens new perspectives in the nutrition sector. However, effective evaluation of the significant safety components is required before extending their use to livestock and veterinary medicine. View Full-Tex

Essential Oil Stabilisation by Response Surface Methodology (RSM): Nanoemulsion Formulation, Physicochemical, Microbiological, and Sensory Investigations

International audienceThis manuscript aimed to optimise the encapsulation of Thymus capitatus essential oil into nanoemulsion. Response Surface Methodology results were best fitted into polynomial models with regression coefficient values of more than 0.95. The optimal nanoemulsion showed nanometer-sizeddroplets (380 nm), a polydispersity index less than 0.5, and a suitable Zeta potential (−10.3 mV). Stability results showed that nanoemulsions stored at 4 ◦C were stable with the lowest d3,2, PolyDis- persity Index (PDI), and pH (day 11). Significant ameliorations in the capacity to neutralise DPPHradical after the encapsulation of the antimicrobial efficacy of thyme essential oil were recorded. S. typhimurium growth inhibition generated by nanoencapsulated thyme essential oil was 17 times higher than by bulk essential oil. The sensory analysis highlighted that the encapsulation of thymeessential oil improved enriched milk’s sensory appreciation. Indeed, 20% of the total population attributed a score of 4 and 5 on the scale used for milk enriched with nanoemulsion. In comparison, only 11% attributed the same score to milk enriched with bulk essential oil. The novel nanometricdelivery system presents significant interest for agroalimentary industrie

Nutritional and health benefits of essential oils in dairy cows

International audienceScientific data supporting the efficacy of Essential oils (EOs) in livestock as anti-inflammatory, antibacterial and antioxidant molecules accumulate over time; however, the cumulative evidence is not always sufficient. Still, so far, the MILKQUA project is the first to evaluate, by a combined OMICS approach, the possible use of selected EOs in the nutrition sector and forthe treatment of mastitis in dairy cows. Given the importance of the DOHaD concept (Developmental Origin of Health and Diseases), we emphasized EOs’ impact, when included in calves’ diet, on food efficiency and animal growth. We also tested EOs direct curative effects on inflamed mammary gland and isolated Blood Mononuclear Peripheral cells (PBMC). We also assessed the in vitro ruminal fermentation and change in the microbiome content in the presence of both natural and synthetic EOs compounds and decrypted, using several in vitro models, the EOs mechanism of action on the NfKB inflammatory pathway. We present in this communication the results of our interdisciplinary approach