References of "Lognay, Georges"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailQuantification of four Isoflavones in Forages with UPLC®-MS/MS, using the Box-Behnken Experimental Design to Optimize Sample Preparation
Daems, Frédéric ULg; Romnee, Jean-Michel; Rasse, Catherine et al

in Chromatographia (in press)

A performant method for the simultaneous quantification of daidzein, genistein, formononetin and biochanin A in forages using an UPLC®-MS/MS was developed and fully validated. The ultrasound-assisted ... [more ▼]

A performant method for the simultaneous quantification of daidzein, genistein, formononetin and biochanin A in forages using an UPLC®-MS/MS was developed and fully validated. The ultrasound-assisted extraction and enzymatic hydrolysis used in the sample preparation step were optimized using the Box-Behnken experimental design. The optimal extraction conditions used for a representative mix of forage plants were 80°C, 10 min and 55% methanol, and for hydrolysis they were 20°C, 18 h and pH=6. The chromatographic separation was achieved using an Acquity® UPLC® HSS T3 column, with a water/methanol linear gradient containing 0.01% of formic acid at a 0.55 mL min-1 flow rate. The four isoflavones were detected by ESI mass spectrometry in positive ion MRM mode. The method allows high throughput analyses of samples and showed an adequate linear regression model for all isoflavones over a range from 5 to 125 ng mL-1. There was good intra- and inter-day precision (≤ 8.2% and ≤ 7.6%) and accuracy (≤ 11.4% and ≤ 7.1%). The recovery rates were in an acceptable range of 70-120%, except for biochanin A, where the rate was about 50%. Good method repeatability was also observed, and there was no matrix effect or carry-over problem. The sample extracts were stable for at least 6 days of storage at -21°C and 6°C. The method proved to be sensitive, precise and accurate for discriminating a wide variety of forages likely to be grazed by ruminants according to their isoflavone content and to observe the impact storage process on isoflavone content in forages. [less ▲]

Detailed reference viewed: 32 (3 ULg)
Full Text
Peer Reviewed
See detailChanges in the isoflavone concentration in red clover (Trifolium pratense L.) during ensiling and storage in laboratory-scale silos
Daems, Frédéric ULg; Decruyenaere, Virginie ULg; Agneessens, Richard et al

in Animal Feed Science & Technology (in press)

Isoflavones constitute one of the most common categories of nonsteroidal estrogen-like substances belonging to the broad group of phytoestrogens. The highest concentrations in the plant kingdom are found ... [more ▼]

Isoflavones constitute one of the most common categories of nonsteroidal estrogen-like substances belonging to the broad group of phytoestrogens. The highest concentrations in the plant kingdom are found in the Fabaceae family. They have become a focus of research because of their estrogenic or anti-estrogenic effect and potential impact on human health. In recent years, several studies have focused on the impact of biotic and abiotic factors and farming management on the isoflavone concentration in plants and their impact on the composition of cow’s milk. Nevertheless, knowledge about the effect of the ensiling process on isoflavone concentration remains limited. The objective of this work was to study the evolution of the concentrations of four compounds (daidzein, formononetin, genistein and biochanin A) in red clover (Trifolium pratense L.) ensiled at harvest. The impact of the field-drying process was also assessed. The plant material was ensiled in laboratory scale silos using vacuum-packed plastic bags and stored over a 6-month period. The quality of the silages was checked throughout the experiment by determining the pH, lactic acid concentration, volatile fatty acids, crude proteins, cellulose and other chemical characteristics. The isoflavone concentration in fresh plant material was 2050, 1766, 306 and 127 µg/g DM for formononetin, biochanin A, genistein and daidzein, respectively. After 4 days of drying in the field, no significant change in isoflavone concentration was found, except for daidzein, which increased twofold. The laboratory-scale silos experiment, however, showed a decrease in isoflavone concentration during the first 2 weeks, followed by stabilization over the 5 remaining months. The concentrations fell by 26, 39, 66 and 73% for daidzein, genistein, biochanin A and formononetin, respectively. Animals fed with silage would therefore absorb fewer isoflavones than those fed with fresh plant material or hay. [less ▲]

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
See detailInfluence of the secondary endosymbiont Serratia Symbiotica on the resistance to the parasitism in the aphid Acyrthosiphon pisum
Attia, Sabrine; Foray, Vincent; Louâpre, Philippe et al

in Journal of Entomology and Zoology Studies (in press)

Aphids have an obligate association with the primary symbiont Buchnera aphidicola and is known to affect aphid fitness. Aphids commonly harbour other facultative bacterial endosymbionts and may benefit ... [more ▼]

Aphids have an obligate association with the primary symbiont Buchnera aphidicola and is known to affect aphid fitness. Aphids commonly harbour other facultative bacterial endosymbionts and may benefit from their presence through increased resistance to parasitoids [1]. Present results suggest that the ability of hosts to defend against natural enemies depend not only on the presence of symbionts but also on the host genotype. Aphids represent a complex micro-environment for the parasitoid larvae and both the aphid physiology and endosymbiont influence their survival until mummification. [less ▲]

Detailed reference viewed: 86 (5 ULg)
Full Text
Peer Reviewed
See detailBACTERIA MAY CONTRIBUTE TO DISTANT SPECIES RECOGNITION IN ANT-APHID MUTUALISTIC RELATIONSHIPS
Fischer, Christophe ULg; Detrain, Claire; Thonart, Philippe ULg et al

in Insect Science (in press)

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids ... [more ▼]

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant’s ability to distantly discriminate two aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic black bean aphid (Aphis fabae L.) and the non-myrmecophilous pea aphid (Acyrthosiphon pisum Harris) were found to be attractive for the black garden ant (Lasius niger L.). The level of attraction was similar in both assays (control versus one of the aphid species). However, when given a choice between these two aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was in investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results emphasize the importance of investigating the presence and potential effects of microbes in insect symbioses. [less ▲]

Detailed reference viewed: 50 (5 ULg)
Full Text
Peer Reviewed
See detailMechanisms involved in pearlfish resistance to holothuroid toxins
Brasseur, Lola; Parmentier, Eric ULg; Caulier, Guillaume et al

in Marine Biology (2016), 163(129), 1-14

Detailed reference viewed: 23 (6 ULg)
Full Text
See detailIn vitro evaluation of protein precipitation capacity of temperate browse species
Vandermeulen, Sophie ULg; Leblois, Julie ULg; Ramírez-Restrepo, Carlos Alberto et al

Poster (2016, February 05)

European agri-environmental policies are promoting the establishment of shrubs and trees on grasslands. The use of browse as fodder requires knowledge on their nutritive value since intensive production ... [more ▼]

European agri-environmental policies are promoting the establishment of shrubs and trees on grasslands. The use of browse as fodder requires knowledge on their nutritive value since intensive production systems are still relying on expensive and environment-costing protein sources. However, information on the influence of temperate condensed tannins (CT)-containing browse forage on rumen protein metabolism is elusive. The study aimed to assess the protein precipitation capacity (PPC) of 10 temperate browse species and establish the correlation between PPC values and plants CT content. PPC of foliage of 3 individuals per woody plants was measured using 2 model proteins: bovine serum albumin (BSA) and casein. The N content in protein solutions (4.6g/L; pH=6.8) was determined before and after adding each forage sample. Extractable CT concentration was quantified by spectrophotometry. The PPC varied across plant species (P<0.001). Corylus avellana had the highest ability to precipitate casein (52.4%). In contrast, the BSA precipitation (18.3%) of this plant was similar to Cornus sanguinea (12.7%), Quercus robur (12.1%) and Crataegus monogyna (11.0%). CT content ranged from 1.4 in Fraxinus excelsior to 82.7g/kg of depigmented sample in Corylus avellana (P<0.001) and was correlated to BSA (r=0.70; P<0.001) and casein PC (r=0.51; P<0.01). It was concluded that woody species could play a significant role in modifying protein metabolism, but further in vivo trials are required. [less ▲]

Detailed reference viewed: 38 (9 ULg)
Full Text
Peer Reviewed
See detailUse of response surface methodology to optimize samples preparations in laboratory
Daems, Frédéric ULg; Romnee, Jean-Michel; Lognay, Georges ULg

Conference (2016, January 17)

Detailed reference viewed: 15 (6 ULg)
Full Text
Peer Reviewed
See detailAnalytical methods used to quantify isoflavones in cow's milk: a review
Daems, Frédéric ULg; Romnee, Jean-Michel; Heuskin, Stéphanie ULg et al

in Dairy Science and Technology (2016)

This paper provides an update and comprehensive review of the analytical methods used for quantifying isoflavones and their metabolites in cow’s milk. Isoflavones are secondary plant metabolites that are ... [more ▼]

This paper provides an update and comprehensive review of the analytical methods used for quantifying isoflavones and their metabolites in cow’s milk. Isoflavones are secondary plant metabolites that are similar to 17 β-estradiol in chemical structure. They form one of the most common categories of phytoestrogens. Numerous health benefits have been attributed to isoflavones, but many of these compounds are also considered to be endocrine disruptors, with adverse effects on health. These contradictory trends offer an attractive prospect for future research, and therefore, sensitive and reliable analytical methods are required to clarify various issues about isoflavones. For this review, a structured methodology was used to select 26 relevant articles published between 2005 and 2015 from the Scopus and CAB Abstract databases. The review discusses individual steps of the analytical procedures described in these articles, including sample preparation, instrumental analysis and validation. The most commonly used analytical procedure is sample preparation involving liquid-liquid extraction and an enzymatic hydrolysis step followed by liquid chromatography with mass spectrometry analysis. Currently, however, there is no standardized procedure for the sample preparation and analysis of isoflavones in milk. [less ▲]

Detailed reference viewed: 24 (11 ULg)
Full Text
Peer Reviewed
See detailChemical composition of essential oils and floral waters of Mentha longifolia (L.) Huds. from Senegal
Diop, Serigne Mbacké; Guèye, Momar Talla; Ndiaye, Ibrahima et al

in American Journal of Essential Oils and Natural Products (2016), 4(1), 46-49

Essential oils of Mentha longifolia from Senegal were extracted from fresh plants and dried plants in the shade for 7 days. The yields were of 0.39 and 0.32% in the fresh and dried plants respectively ... [more ▼]

Essential oils of Mentha longifolia from Senegal were extracted from fresh plants and dried plants in the shade for 7 days. The yields were of 0.39 and 0.32% in the fresh and dried plants respectively. Analysis of the essential oils, floral waters and the assay of pulegone were carried out by GC/FID and GC/MS. The major compounds identified in the oils were pulegone (52.0 and 42.4%), menthone (14.3 and 21.2%), 1, 8-cineole (13.1 and 11.4%) and isomenthone (9.0 and 13.2%) in the fresh and dried plants, respectively. Analyses revealed that floral waters were also characterized by the same major compounds as essential oils but at different rates. In these floral waters, pulegone constituted 60.2 and 47.0%, 1,8- cineole 7.9 and 19.6%, isomenthone 7.2 and 10.7%, menthone 6.4 and 9.2%, chrysanthenone 6.4 and 3.2% and α-terpineol 3.0 and 2.7% in the fresh and dried plants, respectively. The assay results of pulegone, a hepatotoxic compound, have shown very high levels (444.6 and 393.3mg/g) in both fresh and dried plants. [less ▲]

Detailed reference viewed: 23 (1 ULg)
Full Text
Peer Reviewed
See detailInsecticidal activity of Lavandula angustifolia Mill. against the pea aphid Acyrtosiphum pisum
Attia, Sabrine; Lognay, Georges ULg; Heuskin, Stéphanie ULg et al

in Journal of Entomology and Zoology Studies (2016), 4(1), 118-122

The essential oil of Lavandula angustifolia was investigated for its biocide activity against Acyrtosiphum pisum by fumigation. The oil was characterised by GC-MS revealing that linalool was the most ... [more ▼]

The essential oil of Lavandula angustifolia was investigated for its biocide activity against Acyrtosiphum pisum by fumigation. The oil was characterised by GC-MS revealing that linalool was the most abundant component (38.57%), followed by linalyl acetate (29.95%), 1,8-cineole (13,66%), camphor (13,13%), -pinene (3,14%) and terpinene-4-ol (1,54%). The Mortality was measured upon treatment with oil concentrations ranging from 5 to 25 µl.l-1 of air. The mortality of aphids increased with oil concentration and LC50 values were determined to be 11.2 µl.l-1 of air. The full mixture was also prepared and toxicity was compared with individual constituents. The results showed that the presence of all constituents were necessary to equal the toxicity of the natural oils L. angustifolia oil can provide valuable pesticide activity with significantly lower LC50 values [less ▲]

Detailed reference viewed: 42 (8 ULg)
Full Text
Peer Reviewed
See detailImpact of climatic factors on the release of E-β-caryophyllene from alginate beads
Daems, Frédéric ULg; Bera, François ULg; Lorge, Stéphanie ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2016), 20(2),

Description of the subject. Alginate beads that release semiochemical compounds are interesting biological control devices used to attract the natural enemies of aphids in infested crops. Little ... [more ▼]

Description of the subject. Alginate beads that release semiochemical compounds are interesting biological control devices used to attract the natural enemies of aphids in infested crops. Little information, however, is available about the impact of climatic factors on the release of semiochemicals from this diffusive system. Objectives. The objective of this scoping study was to investigate the impact of temperature, relative humidity and wind speed, on the release of E-β-caryophyllene from alginate beads. Method. The impact of the three climatic factors on the release of E-β-caryophyllene from alginate beads was evaluated using a Box-Behnken experimental design and a laboratory scale volatile collection system. The influence of relative humidity on bead water content and size, with and without this semiochemical, was also investigated using a gravimetric method and an easy-to-use photographic device, respectively. Results. The results showed that an increase in temperature caused a significant increase in the E-β¬-caryophyllene release rate. Neither relative humidity nor airflow, however, had a significant effect on the release of this semiochemical when relative humidity and wind speed ranged from 33% to 75% and from 6.61 x10-4 m.s-1 to 2.05 x10-2 m.s-1, respectively. The isotherm curves obtained were characteristic of food products and biopolymer materials. The isotherm shapes were not modified by the incorporation of the semiochemical into alginate beads, and showed an important increase in water content when relative humidity values exceeded 85%. Fortunately, this water content increase did not affect bead size, which facilitates the calculation of E-β-caryophyllene release. Conclusion. The present study shows for the first time the impact of the three main climatic factors on the release of E-β-caryophyllene from alginate beads. It allows learning more about how these biological control devices operate in order to optimize future field trials. [less ▲]

Detailed reference viewed: 41 (6 ULg)
Full Text
See detailDo changes in atmospheric CO2 concentration affect aphid alarm signaling?
Boullis, Antoine ULg; Appeldoorn, Claire; Oostrom, Marjolein et al

Conference (2015, November 06)

The effects of global atmospheric changes on vegetation and associated insect populations are increasingly studied, but how these gases affect the interactions between herbivore insects and their natural ... [more ▼]

The effects of global atmospheric changes on vegetation and associated insect populations are increasingly studied, but how these gases affect the interactions between herbivore insects and their natural enemies is less clear. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in the behavior of insect prey defenses can change the dynamics of insect populations. The impact of increases in atmospheric carbon dioxide (CO2) concentrations on aphid population dynamic is well documented. However, few publications about their chemical ecology are reported. Aphids are using many chemical signals to communicate with each other or with their environment. For example aphids produce an alarm pheromone to signal the presence of a natural enemy in the colony. For our experiments, aphids Acyrthosiphon pisum (Harris) were reared on Vicia faba L. in home-made Plexiglas® chambers, allowing us to control the CO2 concentration, temperature and humidity. Aphids were reared under both ambient (aCO2 ≈ 400 ppm) and elevated (eCO2 ≈ 800 ppm) CO2 concentration for several generations. Here we quantified the emission of (E)-β-Farnesene (EβF - main compound of alarm pheromone) released by predated aphids reared under ambient or elevated CO2 concentration, with two different methods: a real-time analysis, and the total amount analysis. The EβF content of whole aphid bodies was also analyzed, as well as the escape behavior of aphid colony according to the growing conditions of aphid populations. These results will be discussed in terms of biological control in future climate. [less ▲]

Detailed reference viewed: 65 (10 ULg)
Full Text
Peer Reviewed
See detailA PHEROMONE TRAP MONITORING SYSTEM FOR THE SADDLE GALL MIDGE, Haplodiplosis marginata (von Roser) (DIPTERA: CECIDOMYIIDAE)
Censier, Florence ULg; Heuskin, Stéphanie ULg; SAN MARTIN Y GOMEZ, Gilles et al

in Crop Protection (2015), 80

Outbreaks of saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae) have been reported in Belgium and other European countries since 2010. Because of the sporadic nature of this ... [more ▼]

Outbreaks of saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae) have been reported in Belgium and other European countries since 2010. Because of the sporadic nature of this pest, which can sometimes be very harmful to cereal crops, an effective monitoring tool is required, both to determine the optimal timing for insecticide applications, and to understand the enigmatic population dynamics of this insect. Following the recent identification of the major sex pheromone component of the saddle gall midge, non-2-yl butanoate, a slow-release dispenser was developed using rubber septa. The release rates of 5 mg and 10 mg-loaded dispensers were initially measured under laboratory conditions, and their effectiveness in terms of pheromone loading and use duration was assessed in the field. The experiments showed that sticky traps baited with 5 mg pheromone-loaded rubber dispensers, renewed every 6 weeks, are suitable for accurately monitoring male H. marginata flights. [less ▲]

Detailed reference viewed: 61 (23 ULg)
Full Text
Peer Reviewed
See detailDietary mineral intakes of young Tibetan children living in areas endemic for Kashin-Beck disease: preliminary results of a cross-sectional survey
DERMIENCE, Michael ULg; Mathieu, Françoise; Li, Xiaowei et al

Conference (2015, September 18)

Kashin-Beck disease (KBD) is an endemic and chronic osteochondropathy whose etiology remains unclear. Environmental factors are assumed to be involved, among which the selenium and iodine deficiency is ... [more ▼]

Kashin-Beck disease (KBD) is an endemic and chronic osteochondropathy whose etiology remains unclear. Environmental factors are assumed to be involved, among which the selenium and iodine deficiency is frequently cited. The prevalence rate may be high in some rural areas of the Tibet Autonomous Region. The diet of the rural community is significantly different from the other communities (nomads and city-dwellers), who remains unaffected by KBD. Because their foods are mainly derived from local agriculture and artisanal production, their mineral composition may show significant discrepancies when compared with food composition data. The present survey aims at assessing the mineral dietary intakes of young Tibetan children living in rural areas endemic for the Kashin-Beck disease. A cross-sectional survey enrolling 250 children was carried out. The intakes were recorded for two days, on two different seasons, by the 24-hour food recall method. The minerals investigated were selected for their implication in bone metabolism and a specific food composition table was compiled from the China Food composition (book 1, 2nd edition), the USDA Food search for Windows (Version 1.0, Database version SR23), and a broad investigation on mineral composition of local and traditional Tibetan foods (Dermience et al., 2014). The calculation of daily intakes for the first season is now complete and some trends are emerging. Preliminary results suggest, inter alia, that the intakes of calcium are too low with unfavorable calcium to phosphorus ratio. On the contrary, sodium and manganese intakes are too high and could exceed tolerable upper levels. [less ▲]

Detailed reference viewed: 34 (6 ULg)
Full Text
See detailDoes combining a wheat and pea mixture with methyl salicylate reduces aphid populations in both crops?
Chevalier Mendes Lopes, Thomas ULg; Fassotte, Bérénice ULg; Hatt, Séverin ULg et al

Conference (2015, August 25)

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the ... [more ▼]

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the chemical and structural complexity of vegetation can disrupt their host plants location, the searching efficiency of predators and parasitoids can also be reduced. Therefore, these beneficials may not always be more abundant in such systems. Combining crop associations with attractive semiochemicals for natural enemies can be interesting to solve this problem. In this research, we compared the effect of a wheat and pea pure stand, wheat and pea mixture, and wheat and pea mixture combined with methyl salicylate (MeSA) formulated in alginate gel beads, on the abundance and diversity of aphids and their natural enemies. These were weekly observed on plants during 2013 and 2014 growing seasons. Over these two years, significantly higher numbers of pea aphids (Acyrthosiphon pisum (H.)) were observed in the pure stand of pea compared with both mixtures (with and without MeSA). No significant differences were observed between treatments for wheat aphids (Sitobion avenae (F.), Metopolophium dirhodum (W.) and Rhopalosiphum padi (L.)), which were significantly less abundant than pea aphids. Aphid natural enemies were mainly observed on pea plants. Hoverfly larvae abundance was not significantly different between treatments during both years. The same phenomenon occurred with hoverfly pupae in 2013, while these were significantly more abundant in both mixtures compared with the pure stand in 2014. However, their number did not differ significantly between the mixture with and without MeSA. Few ladybirds and lacewings were observed. No significant differences were observed between treatments for parasitoid mummies in 2013. Their abundance was significantly higher in the pure stand of pea compared with both mixtures in 2014. Results from this study show that mixing wheat and pea is an efficient method to maintain aphid populations at a very low level on pea. The use of MeSA did not show significant effects on natural enemies. However, mixing these crops may be enough to reduce aphid populations under an acceptable threshold. [less ▲]

Detailed reference viewed: 49 (14 ULg)
Full Text
Peer Reviewed
See detailCould alternative solanaceous hosts act as refuges for the tomato leafminer, Tuta absoluta?
Bawin, Thomas ULg; Dujeu, David ULg; De Backer, Lara ULg et al

in Arthropod-Plant Interactions (2015), 9(4), 425-435

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous plants. The characterization of its effective ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous plants. The characterization of its effective host range could help to understand and prevent the dispersion behavior of the insect in the environment. In this study, the ability of T. absoluta to locate and develop on wild (Solanum nigrum, Atropa belladonna, Datura stramonium) and cultivated (Solanum tuberosum) solanaceous plant species under laboratory conditions was assessed. Dual-choice behavioral assays performed in flying tunnels (S. tuberosum versus another plant) revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to the other tested plants. The volatile molecules released by each tested plant species provide some explanations in the observed behavioral discrimination: S. nigrum and S. tuberosum volatile profiles were similar, and were presenting quantitative and qualitative differences with the other tested Solanaceous plants. To determine whether the host plant choice was adaptive or not, we have finally conducted fitness assays, by rearing T. absoluta larvae on each plant species and have shown that Solanum species allowed higher larval survivability and lower development time (from egg to adult emergency) compared to the other plants. We conclude that Solanum species are suitable host plants for T. absoluta, but other Solanaceous plant species could be opportunistically colonized with fewer incidences. [less ▲]

Detailed reference viewed: 77 (22 ULg)
Full Text
Peer Reviewed
See detailPhysicochemical properties and thermal behaviour of African wild mango (Irvingia gabonensis) seed fat
Yamoneka, J.; Malumba Kamba, Paul ULg; Blecker, Christophe ULg et al

in LWT - Food Science and Technology (2015), 64

African wild mango (Irvingia gabonensis) is now recognized for its numerous food and medicinal uses. This plant produces seeds rich in fat, which is traditionally used as a soup thickener. In the present ... [more ▼]

African wild mango (Irvingia gabonensis) is now recognized for its numerous food and medicinal uses. This plant produces seeds rich in fat, which is traditionally used as a soup thickener. In the present study, the fat from Irvingia gabonensis seeds was solvent extracted and characterized. Besides a chemical characterization (fatty acid (FA) and triacylglycerol (TG) profiles), the melting and crystallization behaviour of the extracted fat was studied by complementary techniques: pNMR, DSC and X-ray diffraction in order to get basic information regarding its physical properties and more particularly, about its polymorphism. The seeds from Irvingia gabonensis (IG) represent an important source of lipids (69e75 g/100 g), rich in myristic (49.8%) and lauric acid (37%). Due to its FA composition, this fat can be classified among “lauric fats”. The melting profiles of IG fat indicates that a high amount of fat remains solid at temperatures up to 30 °C; the complete melting was detected at around 40 °C. The most stable polymorph of this fat is the ℬ' 1-form. Moreover, IG fat presents a good oxidative stability due to its low content in unsaturated fatty acid. [less ▲]

Detailed reference viewed: 36 (6 ULg)
Full Text
Peer Reviewed
See detailValidation d'une méthode d'analyse quantitative de l'équol par UPLC®-MS/MS dans le lait de vache - Application aux laits commercialisés en Wallonie (Belgique)
Daems, Frédéric ULg; Lognay, Georges ULg; Romne, Jean-Michel et al

Conference (2015, May 27)

Dans le cadre d’un projet intitulé «PhytoHealth », une méthode d’analyse quantitative de l’équol dans le lait a été développée et validée selon les recommandations de l’EMA/CVMP/VICH/463202/2009. Celle-ci ... [more ▼]

Dans le cadre d’un projet intitulé «PhytoHealth », une méthode d’analyse quantitative de l’équol dans le lait a été développée et validée selon les recommandations de l’EMA/CVMP/VICH/463202/2009. Celle-ci est constituée d’une étape d’hydrolyse enzymatique, suivie d’une double extraction liquide/liquide et d’une analyse par chromatographie liquide ultra performante couplé à un spectromètre de masse en tandem (UPLC®-MS/MS). Une fois les différents paramètres tels que la fiabilité, sensibilité et/ou robustesse de la méthode confirmées, celle-ci a permis, pour la première fois, d’estimer la teneur en équol d’ échantillons de laits commercialisés en Wallonie. Une Cinquantaine de laits ont été prélevés aléatoirement dans les commerces durant une période définie. Tous les échantillons possédaient une teneur en équol ≥ 10ng.mL-1. En comparant les valeurs moyennes, on a constaté qu’il n’y avait pas de différence entre les 4 catégories de laits analysés (entier, demi-écrémé, écrémé et cru). Par contre, une différence hautement significative a pu être observée entre les laits provenant de la filière biologique et ceux de la filière conventionnelle. Dans le premier cas, les teneurs varient entre 10 et 50 ng.mL-1 par contre, dans le second, elles varient entre 70 et 130 ng.mL-1. Cet impact de la filière biologique sur la teneur en équol dans les laits a pu être confronté à d’autres études européennes et confirmé. [less ▲]

Detailed reference viewed: 56 (7 ULg)
Full Text
Peer Reviewed
See detailApplication du plan d’expérience de Box-Behnken et de la méthodologie des surfaces de réponses pour optimiser une méthode de quantification de phyto-œstrogènes dans les fourrages
Daems, Frédéric ULg; Lognay, Georges ULg; Romnee, Jean-Michel et al

Conference (2015, May 27)

Dans le cadre d’un projet de valorisation des prairies, intitulé « PhytoHealth », une méthode d’analyse quantitative constituée d’une étape d’extraction à l’aide d’un bain à ultrasons, suivi d’une ... [more ▼]

Dans le cadre d’un projet de valorisation des prairies, intitulé « PhytoHealth », une méthode d’analyse quantitative constituée d’une étape d’extraction à l’aide d’un bain à ultrasons, suivi d’une hydrolyse enzymatique et d’une analyse par UPLC®-MS/MS a été développée pour assurer le dosage de phyto-œstrogènes dans les fourrages. Pour alléger l’optimisation de la préparation des échantillons, la méthodologie des surfaces de réponses a été utilisée. Un plan d’expérience de Box-Behnken a été appliqué aux étapes d’extraction et d’hydrolyse. Parmi les différents facteurs pris en compte, les impacts de la nature du solvant utilisé lors de l’extraction ainsi que la température et le pH lors de l’hydrolyse, ont clairement pu être mis en évidence. L’ensemble des données générées a également permis de définir des conditions optimales d’extraction et d’hydrolyse pour chacun des composés. Ces conditions n’étant pas identiques pour chacun d’entre eux, un compromis a été trouvé afin de pouvoir analyser l’ensemble de ces composés simultanément. L’ensemble de la méthode a ensuite été validée selon les recommandations de l’EMA/CVMP/VICH/463202/2009, pour confirmer sa fiabilité et robustesse. Cette dernière, combinée au model d’ensilage en sacs sous vide, a permis pour la première fois de suivre la cinétique d’évolution de 4 phyto-œstrogènes (daidzéine, génistéine, formononétine et biochanin A) durant une période d’ensilage. [less ▲]

Detailed reference viewed: 67 (4 ULg)