Caractérisation et stabilité de sources de phospholipides polyinsaturés à intérêts nutritionnels

L'intérêt porté aux phospholipides s'est considérablement développé ces dernières années, particulièrement lorsqu on considère leur rôle de vecteur d'acides gras essentiels et/ou polyinsaturés comme l'acide eicosapentaénoïque ou docosahexaénoïque. Cette propriété des phospholipides a éveillé l'attention des industriels, qui envisagent aujourd hui de les supplémentater à des denrées alimentaires. Toutefois, l'utilisation de molécules pures s'avère totalement irréaliste, du fait de coûts trop importants et d'une mise en œuvre très difficile. La solution réside donc dans l'utilisation de sources naturelles de phospholipides polyinsaturés. La caractérisation de nouvelles sources est donc une étape cruciale dans le développement de produits supplémentés en phospholipides. Ce travail de thèse a permis de mettre au point des méthodes d'extraction, de purification, de séparation et de quantification des phospholipides afin de sélectionner des sources potentielles riches en phospholipides polyinsaturés. Mais la présence d'insaturations rend ces molécules sensibles aux phénomènes oxydatifs rencontrés lors des procédés. L'autre partie de cette thèse a donc été de mettre au point des méthodes permettant l'identification des produits de dégradation des phospholipides insaturés, générés lors du traitement thermique, ainsi que de déterminer leur cinétique d'oxydation. Ce travail de thèse a également permis de montrer que les phospholipides sont plus stables que les triglycérides vis-à-vis du traitement thermique.The interest given to phospholipids has considerably increased since several years, more particularly when considering their role of fatty acids vector such as polyunsaturated (eicosapentaenoic and docosahexaenoic acids) or essential fatty acids. This property led manufacturers to envisage food supplementation with phospholipids. However, the use of pure molecules proves to be totally unrealistic due to very high costs and very difficult implementation. The solution lies in the use of natural raw materials as sources of polyunsaturated phospholipids. Thus, the characterization of new sources is a crucial step in the development of new food products, supplemented with phospholipids. This work allowed developing extraction methods, purification methods, and separation and quantification methods of phospholipids in order to select new potential sources rich in polyunsaturated phospholipids. Double bonds of unsaturated molecules are prone to reactions of oxidation, such as thermal treatment, widespread in food processing. The second part of this work was to develop methods to identify phospholipids degradation products, generated during oxidation processes and to determine their kinetics of oxidation. This work allowed showing that phospholipids are more stable against thermal oxidation compared to their triacylglycerols homologues

Caractérisation et stabilité de sources de phospholipides polyinsaturés à intérêts nutritionnels

L'intérêt porté aux phospholipides s'est considérablement développé ces dernières années, particulièrement lorsqu on considère leur rôle de vecteur d'acides gras essentiels et/ou polyinsaturés comme l'acide eicosapentaénoïque ou docosahexaénoïque. Cette pThe interest given to phospholipids has considerably increased since several years, more particularly when considering their role of fatty acids vector such as polyunsaturated (eicosapentaenoic and docosahexaenoic acids) or essential fatty acids. This p

Caractérisation et stabilité de sources de phospholipides polyinsaturés à intérêts nutritionnels

L intérêt porté aux phospholipides s est considérablement développé ces dernières années, particulièrement lorsqu on considère leur rôle de vecteur d acides gras essentiels et/ou polyinsaturés comme l acide eicosapentaénoïque ou docosahexaénoïque. Cette propriété des phospholipides a éveillé l attention des industriels, qui envisagent aujourd hui de les supplémentater à des denrées alimentaires. Toutefois, l utilisation de molécules pures s avère totalement irréaliste, du fait de coûts trop importants et d une mise en œuvre très difficile. La solution réside donc dans l utilisation de sources naturelles de phospholipides polyinsaturés. La caractérisation de nouvelles sources est donc une étape cruciale dans le développement de produits supplémentés en phospholipides. Ce travail de thèse a permis de mettre au point des méthodes d extraction, de purification, de séparation et de quantification des phospholipides afin de sélectionner des sources potentielles riches en phospholipides polyinsaturés. Mais la présence d insaturations rend ces molécules sensibles aux phénomènes oxydatifs rencontrés lors des procédés. L autre partie de cette thèse a donc été de mettre au point des méthodes permettant l identification des produits de dégradation des phospholipides insaturés, générés lors du traitement thermique, ainsi que de déterminer leur cinétique d oxydation. Ce travail de thèse a également permis de montrer que les phospholipides sont plus stables que les triglycérides vis-à-vis du traitement thermique.The interest given to phospholipids has considerably increased since several years, more particularly when considering their role of fatty acids vector such as polyunsaturated (eicosapentaenoic and docosahexaenoic acids) or essential fatty acids. This property led manufacturers to envisage food supplementation with phospholipids. However, the use of pure molecules proves to be totally unrealistic due to very high costs and very difficult implementation. The solution lies in the use of natural raw materials as sources of polyunsaturated phospholipids. Thus, the characterization of new sources is a crucial step in the development of new food products, supplemented with phospholipids. This work allowed developing extraction methods, purification methods, and separation and quantification methods of phospholipids in order to select new potential sources rich in polyunsaturated phospholipids. Double bonds of unsaturated molecules are prone to reactions of oxidation, such as thermal treatment, widespread in food processing. The second part of this work was to develop methods to identify phospholipids degradation products, generated during oxidation processes and to determine their kinetics of oxidation. This work allowed showing that phospholipids are more stable against thermal oxidation compared to their triacylglycerols homologues.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Combined microplate-ABTS and HPLC-ABTS analysis of tomato and pepper extracts reveals synergetic and antagonist effects of their lipophilic antioxidative components

International audienceThe antioxidant capacity of 9 pure lipophilic compounds was examined by microplate-ABTS and HPLCABTS,using similar experimental conditions. Results obtained showed that HPLC-ABTS method can beused for a rapid determination of individual antioxidant capacity of compounds in standard solutionsor complex mixtures. The application of both methods to real lipophilic extracts from tomato (Solanumlycopersicum L.), green and red peppers (Capsicum annuum) reveals possible interactions betweenantioxidants. Thus, synthetic mixtures of two compounds identified in tomato and peppers weremeasured using microplate-ABTS and HPLC-ABTS. Synergistic effects were observed between(b-carotene-capsanthin) (1:9) and (1:1), (a-tocopherol-capsanthin) (1:9), (lutein-lycopene) (9:1)and (capsanthin-d-tocopherol) (9:1). On the contrary, antagonistic effects were observed for(lutein-d-tocopherol) and (a-tocopherol-d-tocopherol). The interactions observed with two-compoundmixtures are not systematically observed in the natural lipophilic extracts from tomato, green and redpeppers, probably since extracts are more complex and are susceptible to cause interferences

Effects of industrial processing on folate content in green vegetables.

International audienceFolates are described to be sensitive to different physical parameters such as heat, light, pH and leaching. Most studies on folates degradation during processing or cooking treatments were carried out on model solutions or vegetables only with thermal treatments. Our aim was to identify which steps were involved in folates loss in industrial processing chains, and which mechanisms were underlying these losses. For this, the folates contents were monitored along an industrial canning chain of green beans and along an industrial freezing chain of spinach. Folates contents decreased significantly by 25% during the washing step for spinach in the freezing process , and by 30% in the green beans canning process after sterilisation, with 20% of the initial amount being transferred into the covering liquid. The main mechanism involved in folate loss during both canning green beans and freezing spinach was leaching. Limiting the contact between vegetables and water or using steaming seems to be an adequate measure to limit folates losses during processing

Determination of active radical scavenging compounds in polar fruit and vegetable extracts by an on-line HPLC method

Cited by (10) Recommended articles (6)ElsevierLWT - Food Science and TechnologyVolume 62, Issue 1, Part 1, June 2015, Pages 152-159LWT - Food Science and TechnologyDetermination of active radical scavenging compounds in polar fruit and vegetable extracts by an on-line HPLC methodAuthor links open overlay panel, , , , , , ,a Equipe de Chimie Analytique des Molécules Bio-Actives, IPHC-DSA, Université de Strasbourg, CNRS, 74, Route du Rhin, 67400 Illkirch, Franceb Centre Européen d'Etude du Diabète, Université de Strasbourg, DIATECH EA 7294, Boulevard René Leriche, 67200 Strasbourg, Francec Aerial, 250 Rue Laurent Fries, Parc d'innovation, 67412 Illkirch, Franced Interprofession des Fruits et Légumes d'Alsace, 11, Rue Jean Mermoz, 68127 Sainte Croix en Plaine, FranceReceived 12 August 2014, Revised 27 November 2014, Accepted 3 January 2015, Available online 10 January 2015.https://doi.org/10.1016/j.lwt.2015.01.004Get rights and contentAbstractFruit and vegetables are believed to help fight against oxidative stress, given their natural content in radical scavenging compounds. Natural polyphenols neutralize reactive oxygen species by means of electron and hydrogen atom transfers. An HPLC method, hyphenated with a post-column reaction system relying on ABTSradical dot+ bleaching assay was applied in order to quantify the chemical activity of radical scavenging compounds in red cabbage, onion, quince, sweet cherry, strawberry, carrot and tomato. Hyphenated to the ABTSradical dot+ post-column reaction system, this method showed high antioxidant capacity notably in cherry, quince, onion, or red cabbage. Structural analysis of the compounds of interest showed the implication of several cyanidins and caffeoylquinic acids in cherry. Quince and red cabbage were found highly active through the presence of respectively caffeoylquinic acids, and an important content of diverse cyanidins variously glycosylated and acylated. The onion extract revealed a chemical core structure (quercetin) responsible for its antioxidant capacity. Moreover, our results showed that depending on the glycosylation profile of these compounds, their radical scavenging capacity can be very different