ORBi Collection: Food science

Antioxidant capacity of hydrophilic food matrices: optimization and validation of ORAC assay.

Mon, 10 Jun 2013 12:19:50 GMT

Title: Antioxidant capacity of hydrophilic food matrices: optimization and validation of ORAC assay.

Author, co-author: Kevers, Claire; Sipel, Arnaud; PINCEMAIL, Joël; Dommes, Jacques

Abstract: It is widely accepted that ORAC is a useful method for assessing food extracts that contain various antioxidants. The principal aim of this study was to validate the ORAC assay. We first identified parameters that can interfere with the ORAC assay and we optimized it. Then, experiments were conducted to determine the limits of linearity and response function, to determine the accuracy profiles to circumvent some of the drawbacks of traditional validation procedures. Trueness, selectivity and limits of quantification of the method were also determined. Our objective of ORAC method validation is thus to give guarantees that most of the results generated during use of this method will be close enough to unknown true value of antioxidant capacity of food matrices. The validation results indicate that the described method will give accurate and reliable results for Trolox equivalent values ranging from 50 to 200 µmol/L.

Sample dilution influences the determination of antioxidant capacity in food. How to minimize it?

Mon, 10 Jun 2013 12:00:31 GMT

Title: Sample dilution influences the determination of antioxidant capacity in food. How to minimize it?

Author, co-author: Sipel, Arnaud; Kevers, Claire; PINCEMAIL, Joël; Grygel, Pierre-Gabriel; DEFRAIGNE, Jean; Dommes, Jacques

Abstract: The influence of sample dilution on the measurement of antioxidant capacity was analyzed. To ensure the reproducibility of results it is necessary to realize such scarce investigations. This study focuses on different antioxidant capacity assays, commonly used for the analysis of pure substances and food extracts. For all compounds and foods tested in most of the four assays (TEAC, DPPH and ORAC), effects of sample dilution on the measured (and recalculated) antioxidant capacity were observed, differences up to 28% between dilutions. An extrapolation method was proposed to obtain a “real value” thus to minimize the effects of the sample dilution. This extrapolation method is relatively simple, based on a linear regression of 4 or 5 appropriate dilutions of the sample and applicable to the various assays. The use of such a method will improve the consistency of inter-laboratory antioxidant capacity data and thus permit better comparisons. In contrast, there was no dilution problem with FRAP assays.

Genetics of beef and milk fatty acid composition

Mon, 03 Jun 2013 10:12:34 GMT

Title: Genetics of beef and milk fatty acid composition

Author, co-author: Soyeurt, Hélène; Beitz, Donald

Individual methane predictions from milk mid-infrared spectra of Holstein dairy cows.

Fri, 31 May 2013 17:12:46 GMT

Title: Individual methane predictions from milk mid-infrared spectra of Holstein dairy cows.

Author, co-author: Soyeurt, Hélène; Vanlierde, Amélie; Dehareng, Frédéric; Froidmont, Eric; Fernández Pierna, Juan; Grelet, Clément; Bertozzi, Carlo; Kandel, Purna Bhadra; Colinet, Frédéric; Gengler, Nicolas; Dardenne, Pierre

Review: Milk composition as management tool of sustainability

Fri, 31 May 2013 08:11:19 GMT

Title: Review: Milk composition as management tool of sustainability

Author, co-author: Arnould, Valérie; Reding, Romain; Bormann, Jeanne; Gengler, Nicolas; Soyeurt, Hélène

Abstract: The main objective of this paper is the use of milk composition data as a management tool. Milk composition, and in particular, milk fat content and fatty acid profiles may be significantly altered due to a variety of factors. These factors are reviewed in the literature; they include diet, animal (genetic) selection, management aspects and animal health. Changes in milk composition can be used as an indicator of the animal’s metabolic status or the efficiency of the feed management system. The advantages of using this kind of data as a management tool would be to allow the early detection of metabolic or management problems. The present review suggests that milk and, especially milk fat composition may be used as a sustainability management tool and as a monitoring and prevention tool for several pathologies or health disorders in dairy cattle. Further, due to the use of MIR technology, these tools may be easily implemented in practice and are relatively cheap. In the field, milk labs or milk recording agencies would be able to alert farmers whenever threshold values for disease were reached, allowing them to improve their dairy production from an economic, ecological and animal (welfare) point of view.

l'huile végétale sous la loupe

Tue, 28 May 2013 14:09:38 GMT

Title: l'huile végétale sous la loupe

Author, co-author: Danthine, Sabine

Optimization of the formation of vinyldithiins, therapeutic compounds from garlic

Wed, 15 May 2013 19:19:00 GMT

Title: Optimization of the formation of vinyldithiins, therapeutic compounds from garlic

Author, co-author: DETHIER, Bérénice; Hanon, Emilien; Maayoufi, Said; Nott, Katherine; Fauconnier, Marie-Laure

Abstract: Allyl sulfides, ajoenes and vinyldithiins are the three main groups of volatile organosulfur compounds that are formed when garlic is crushed. The manner garlic is processed (nature of the extraction medium, temperature…) has a major influence on their relative proportion and the amounts produced. It has been proven recently that the vinyldithiins are at the origin of garlic’s capacity to prevent adipocytes development. Their incorporation in garlic-based nutraceuticals is thus particularly interesting. In this context, this work aims to optimize the production of vinyldithiins from garlic. After having determined the best garlic origin (Spanish) and the best oil for the extraction (olive or sunflower oil), the extraction conditions were optimized (1/2 (w/w garlic oil), 37 °C, 6 h) and 133 mg of vinyldithiins was obtained from 100 g of fresh garlic. Carrying out the extraction under microwave irradiation allowed increasing the yield 3.6-fold (yield 486 mg of vinyldithiins from 100 g of fresh garlic). This study may also contribute to the development of new garlic derived high value products by enhancing the comprehension of their formation.

Egg Production Performance of the Local Kabyle Hen and its Crossbreeds with ISA-Brown Strain in Semi-Intensive Conditions

Thu, 09 May 2013 20:34:16 GMT

Title: Egg Production Performance of the Local Kabyle Hen and its Crossbreeds with ISA-Brown Strain in Semi-Intensive Conditions

Author, co-author: Moula, Nassim; Mamadou Tandiang, Diaw; Salhi, Abdellah; Farnir, Frédéric; Antoine-Moussiaux, Nicolas; Leroy, Pascal

Abstract: A cross between the ISA-Brown industrial strain and an Algerian local (Kabyle) breed was compared with the Algerian local (Kabyle) hen. The comparison during the egg production period was done in individual cages, in a ventilated henhouse without any particular isolation. The same commercial diet has been provided over three time periods (35 to 36 weeks, 50 to 51 weeks and 65 to 66 weeks of age). Egg number and body weight at first egg was significantly lower in the Kabyle local breed. Mortality was almost equal during the breeding period and the egg production periods for the two genotypes. The Kabyle hen eggs, in spite of a weight which was lower (43.70 to 53.37 g according to the age), gave yolk to albumen ratio similar to the ISAKAB cross (0.52 to 0.58 according to age). Finally, the ISAKAB cross was better in terms of egg production and egg quality than the local hen, in test conditions.

Influence of drying and hydrothermal treatments on the denaturation of corn proteins

Mon, 29 Apr 2013 13:18:34 GMT

Title: Influence of drying and hydrothermal treatments on the denaturation of corn proteins

Author, co-author: Odjo, Djosse Psijus Sylvanus; Malumba Kamba, Paul; Bera, François

Abstract: Corn (Zea mays L.) is the most abundant cereal grain produced in the world. It also provides a significant amount of protein in human and animal diets. During drying corn grains undergo several alterations including protein denaturation. A series of studies have been conducted in order to understand mechanisms behind denaturation of corn proteins during drying and heat moisture treatments. Using a laboratory fluidized-bed dryer, a flint corn variety have been dried between 54° and 130°C and subjected to different analyses from a qualitative point of view with a sequential extraction of corn protein fractions and from a quantitative point of view with the modeling of salt-soluble proteins using Promatest assay. Albumin, globulin and zein solubilities dropped significantly when the drying temperature increased. The electrophoretic patterns of zein and glutelin-G1 were not significantly modified, although the solubility of zein was affected by the drying temperature. The analysis of the different protein group solubilities suggested that denaturation mechanisms other than the creation of new disulfide bonds occurred during the drying of corn at high temperature. The study of the effect of heat treatments on the extractability of salt-soluble proteins shows that temperature; moisture content and time of processing greatly influence their kinetic denaturation. Modeling of salt-soluble proteins reveals that the evolution of extractible salt-soluble proteins content of corn kernels during drying at high temperature is more correctly described with a second order kinetic reaction. Investigations continue in order to understand protein denaturation and influence in functional properties and end-use of corn protein-based products.

Effect of heat treatment of rennet skim milk induced coagulation on the rheological properties and molecular structure determined by synchronous fluorescence spectroscopy and turbiscan

Fri, 26 Apr 2013 07:47:03 GMT

Title: Effect of heat treatment of rennet skim milk induced coagulation on the rheological properties and molecular structure determined by synchronous fluorescence spectroscopy and turbiscan

Author, co-author: Blecker, Christophe; Habib-Jiwan, Jean-Michel; Karoui, Ramdhane

Abstract: Heat treatment applied to milk induces denaturation of whey proteins, leading to a complex mixture of whey protein and whey protein coated casein micelles. The present paper investigates the effects of heat treatment (60 and 80 °C during 20 min) and rennet-induced coagulation temperature (30 and 40 °C) determined by rheology, synchronous fluorescence spectroscopy (SFS) and turbiscan measurements. The gelation times determined by rheology and SFS increased with the increase of heat treatment applied to milk. The rise in temperature induced a decrease in the maximum curd firming rate and an increase in the viscosity of the investigated milk samples. The principal component analysis (PCA) applied, sepa- rately, to the SF and turbiscan spectra showed a clear discrimination between: (i) raw milks and heated milks; and (ii) milks renneted at 30 °C from those renneted at 40 °C. The results showed the ability of SFS as a rapid and non-destructive technique for the: (i) monitoring network structure and molecular inter- action during the coagulation process; and (ii) determination of gelation time of rennet-induced coagu- lation of studied milk samples.

Effects of Processing on the Compositions and Physicochemical Properties of Fibre Concentrate from Cooked Fruit Pomaces

Fri, 26 Apr 2013 07:41:03 GMT

Title: Effects of Processing on the Compositions and Physicochemical Properties of Fibre Concentrate from Cooked Fruit Pomaces

Author, co-author: Rabetafika, Holy-Nadia; Bchir, Brahim; Aguedo, Mario; Paquot, Michel; Blecker, Christophe

Abstract: This study examined the influence of applied tech- nologies namely desugaring, grinding, and bleaching on the compositions (cellulose, hemicelluloses, lignins, and pectins), physicochemical properties (water-holding capacity (WHC), swelling capacity (SWC), oil-holding capacity (OHC)) and the colour of dietary fibre (DF) during the production of fibre concentrates from unusual cooked apple and pear pomaces. Thermogravimetric analysis (TGA) and optical microscopy were also performed to monitor process-induced modifica- tion. All the processing conditions affected the compositions and physicochemical properties of DF. The bleaching treat- ment induced the greatest changes on DF producing yellow cellulose-rich fibre concentrates with improved WHC from 3.2 to 10.0 g/g and improved SWC from 4.0 to 8.8 ml/g. Otherwise, reduction of the particle size influenced hydration properties and colours of DF. WHC and SWC tended to increase with the particle size whereas smaller granulometric size increased the lightness of fibres. Desugaring increased the DF content in both pomaces by 1.2-fold with slight modifica- tion of apple insoluble dietary fibre ratio. Fibre concentrates had improved WHC and SWC up to 1.4-fold. All processes had no significant effect (p < 0.05) on OHC of DF except with ultrafine apple fibre concentrates. Results showed that pro- cessing had overall positive effects on DF contents and hy- dration properties of pomaces from cooked fruits. Bleached fibre concentrates from apple pomace had the highest WHC (10.0 g/g) whereas that of pear had the highest fibre content (89.9 %). Fibres from cooked fruit pomaces may therefore be used as textural ingredients or functional foods.

Effects of Processing on the Compositions and Physicochemical Properties of Fibre Concentrate from Cooked Fruit Pomaces

Fri, 26 Apr 2013 07:41:03 GMT

Rapport d'activités final du premier mandat (du 1er février 2011 au 31 janvier 2013) : ProFARMilk, variabilité et amélioration des aptitudes à la transformation fermière du lait

Tue, 09 Apr 2013 08:17:05 GMT

Title: Rapport d'activités final du premier mandat (du 1er février 2011 au 31 janvier 2013) : ProFARMilk, variabilité et amélioration des aptitudes à la transformation fermière du lait

Author, co-author: Gengler, Nicolas; Sindic, Marianne; Dardenne, Pierre; Colinet, Frédéric; Vanden Bossche, Sandrine; Troch, Thibault; Sinnaeve, Georges; Dehareng, Frédéric; Abbas, Ouissam; Baeten, Vincent

Determination of chloramphenicol in honey, 1 shrimp and poultry meat with liquid chromatography-mass spectrometry. Validation of the method according to Commission Decision 2002/657/EC

Mon, 08 Apr 2013 12:55:46 GMT

Title: Determination of chloramphenicol in honey, 1 shrimp and poultry meat with liquid chromatography-mass spectrometry. Validation of the method according to Commission Decision 2002/657/EC

Author, co-author: Douny, Caroline; Widart, Joëlle; De Pauw, Edwin; Maghuin-Rogister, Guy; Scippo, Marie-Louise

Abstract: Chloramphenicol (CAP) is an antibiotic used for the treatment of bacterial infections in human and veterinary medicine. The use of CAP was prohibited in the European Union in 1994. Control laboratories are required to use suitably validated analytical methods to check sample compliance with the regulation. A quantitative method based on liquid chromatography coupled to isotopic dilution tandem mass spectrometry (LC–IDMS/MS) was developed for the determination of chloramphenicol in honey, shrimp and poultry meat. The experimental protocol consisted of a liquid-liquid extraction with ethyl acetate. Separation and detection were realized respectively by a 2690 Waters HPLC (Milford, MA, USA) and a Micromass Triple Quadrupole mass spectrometer (Micromass, Manchester, UK), equipped with an Electrospray source. The effects of mobile phase additives on the response of LC/ESI/MS were examined. Two different HPLC columns were tested: the X-Terra from Waters and the Alltima HP C18 HL from Alltech (Deerfield, IL, USA). A validation of the method was conducted according to the EU criteria for the analysis of chloramphenicol in foods. The decision limits (CCα) were 0.04, 0.03, 0.07 µg kg-1 and the detection capabilities (CCβ) were 0.05, 0.04, 0.08 µg kg-1 for honey, shrimp and poultry meat respectively. Those values are below the minimum required performance limit (MRPL) set at 0.3 µg kg-1 by the EU and 0.1 µg kg-1 by Belgium. Our protocol has the advantage to propose a unique extraction method working as well for honey, shrimp and poultry meat, contrary to similar published methods in which a different extraction method is used for each type of matrix.

Etude de la variabilité des aptitudes à la transformation laitière en Région wallonne basée sur l'utilisation de la spectrométrie infrarouge

Sun, 24 Mar 2013 04:00:53 GMT

Title: Etude de la variabilité des aptitudes à la transformation laitière en Région wallonne basée sur l'utilisation de la spectrométrie infrarouge

Author, co-author: Colinet, Frédéric; Troch, Thibault; Vanden Bossche, S.; Soyeurt, Hélène; Gengler, Nicolas; Abbas, O.; Baeten, V.; Dehareng, F.; Sinnaeve, G.; Dardenne, P.; Sindic, Marianne

Journée de rencontre entre L'institut des Radio-Elements et L'Université de Liège

Mon, 18 Mar 2013 12:37:27 GMT

Title: Journée de rencontre entre L'institut des Radio-Elements et L'Université de Liège

Author, co-author: Debois, Valérie; Gobert, Sylvie

Abstract: Présentation des activités du CART (Caroline Douny), de l'Unité D'Analyses, Qualité et Risques (JP Bathélémy), du Bureau Envirinnement et Analyses de Gembloux (Ph Maesen), du laboratoire des ressources Hydriques (V Debbait) et du laboratoire d'Océanologie (S Gobert).Pistes de Collaborations.

Effects of extraction solvents on phenolic contents and antioxidant activities of Tunisian date varieties (Phoenix dactylifera L.)

Fri, 15 Mar 2013 04:00:09 GMT

Title: Effects of extraction solvents on phenolic contents and antioxidant activities of Tunisian date varieties (Phoenix dactylifera L.)

Author, co-author: Kchaou, W; Abbès, F; Blecker, Christophe; Attia, H; Besbes, S

Abstract: Second-grade dates (Phoenix dactylifera L.), with hard texture, from six Tunisian cultivars were analysed for their composition and antioxidant activities. Results showed predominance of total sugars and a relatively low content of protein, fat andash. On the other hand, optimisation of extraction of antioxidant was carried using five different solvents. The highest level of phenolic compounds for all dates varieties was found in the 70% acetone extract. This level ranged from 199.43 to 576.48 mg of GAE/100 g fresh weight. However, extraction into 50% methanol gave the highest antioxidant activity from 89.55 to 109.67 mg equivalents of ascorbic acid/g fresh weight. For both two olvents, Bejo exhibited the highest phenolic content and total antioxidant activity, while Baydh El Hamam presented the owest. A positive linear correlation between total antioxidant activity and phenolic contents was observed (R2 = 0.83; R2 = 74 for acetone/H2O and methanol/H2O, respectively). The antioxidant activity of acetone/H2O and methanol/H2O extracts was carried using DPPH radical-scavenging activity and reducing power. These results showed that dates had strongly scavenging activity on DPPH reaching 90.12% in methanol/H2O from Deglet Nour. Whereas, acetone/H2O showed the best reducing power which Bejo was significantly higher than the other varieties. This study demonstrates the potential antioxidant activity with Tunisian date, that we can use these natural extracts as food additives in replacement of synthetic compounds.

Evaluation de l’impact de la ﬁliere de production porcine sur les caractéristiques des jambons de l’IGP (Indication Géographique Protégée) Jambon d’Ardenne

Tue, 12 Mar 2013 14:09:07 GMT

Title: Evaluation de l’impact de la ﬁliere de production porcine sur les caractéristiques des jambons de l’IGP (Indication Géographique Protégée) Jambon d’Ardenne

Author, co-author: Dzaomuho-Lenieregue, Phidias; Eloundou Mballa, Pierre; Sindic, Marianne; Mabon, Nicolas

Abstract: The aim of this study is to evaluate the influence of pork production sector on technological behavior of raw material, properties of the ham final product and consumer preferences. An experimental manufacturing assay of Ardenne Ham has been conducted for this purpose. Results show few incidence of pork production conditions on technological properties and chemical or sensory characteristics of hams. The preference tests, carried out with a sensory panel using several criteria, showed that consumers were able to distinguish two groups of hams, according to their fat content. They have a preference for lower-fat ham from one of the studied sectors. Method of multicriteria decision shows no overall preference for one of the submitted ham.

Chemical Composition and Antioxidant Activity of Essential Oil of Ocimum basilicum Leaves from the Northern Region of Algeria

Wed, 06 Mar 2013 11:00:53 GMT

Title: Chemical Composition and Antioxidant Activity of Essential Oil of Ocimum basilicum Leaves from the Northern Region of Algeria

Author, co-author: Hadj Khelifa, L.; Brada, Moussa; Brahmi, F.; Achour, D.; Fauconnier, Marie-Laure; Lognay, Georges

Abstract: Ocimum basilicum essential oil (Algerian species), which is extracted from dried leaves with an output of 1.98 ± 0.01%, is yellow pale. Its chemical composition has been investigated by GC/MS and GC/FID. Fourty compounds have been identified accounting for 97.4%. The major compounds were: Linalool (32.83%), linalyl acetate (16%), elemol (7.44%), geranyl acetate (6.18%), myrcene (6.12%), allo-ocimene (5.02%), α-terpineol (4.9%), (E)-β-ocimene (3.68%) and neryl acetate (3.45%). O. basilicum essential oil was screened for its in vitro antioxidant activity using DPPH assay. The results showed that the concentration of the essential oil needed to scavenge 50% of DPPH, was 83.54 mg/ml lower than that of vitamin E (22.0 mg/ml) and therefore acts as a natural antioxidant agent.

Neuartige Management Tools für Milchviehbetrieb mittels Spektralanalytik

Tue, 05 Mar 2013 11:20:01 GMT

Title: Neuartige Management Tools für Milchviehbetrieb mittels Spektralanalytik

Author, co-author: Arnould, Valérie; Reding, Romain; Bormann, Jeanne; Gengler, Nicolas

Abstract: In den letzten Jahrzenten wurde die Milch- und Fleischproduktion mehr und mehr mit generellen Nachhaltigkeitsfragen in Verbindung gebracht. Sehr oft wird eine bessere Produktionsnachhaltigkeit auch mit ökonomischen Aspekten verbunden. In der Tat liegt die Kunst der modernen Milchproduktion scheinbar vor allem darin, die Produktion (egal ob tier- oder betriebsindividuell) stetig bei möglichst gleichbleibenden oder gar noch geringeren Kosten zu erhöhen. Daneben ist zu bedenken, dass Konsumenten heutzutage neben preislichen Aspekten sehr oft zusätzlich Gesundheitsaspekte ins Spiel bringen, so dass es für Milchbetriebe nicht unwesentlich ist, die Produktion in gewisser Weise diesen Ansprüchen nach zu gestalten. Glücklicherweise können entscheidende Inhaltsstoffe wie der Milchfettgehalt oder das Fettsäuremuster der Milch durch Managementfaktoren wie Zucht, Selektion, Fütterung und Haltungsbedingungen zum Positiven beeinflusst werden und den Anforderungen der Nachfrageseite besser angepasst werden. Genau bei dieser Problematik liegen die Ansatzpunkte der verschiedenen CONVIS Projekte (QuaM, ManageMILK und OptiMIR) im Bereich Spektralanalysen der Milch.