Microwave-Assisted Extraction for Microalgae: From Biofuels to Biorefinery

The commercial reality of bioactive compounds and oil production from microalgal species is constrained by the high cost of production. Downstream processing, which includes harvesting and extraction, can account for 70-80% of the total cost of production. Consequently, from an economic perspective extraction technologies need to be improved. Microalgal cells are difficult to disrupt due to polymers within their cell wall such as algaenan and sporopollenin. Consequently, solvents and disruption devices are required to obtain products of interest from within the cells. Conventional techniques used for cell disruption and extraction are expensive and are often hindered by low efficiencies. Microwave-assisted extraction offers a possibility for extraction of biochemical components including lipids, pigments, carbohydrates, vitamins and proteins, individually and as part of a biorefinery. Microwave technology has advanced since its use in the 1970s. It can cut down working times and result in higher yields and purity of products. In this review, the ability and challenges in using microwave technology are discussed for the extraction of bioactive products individually and as part of a biorefinery approach

Authentication of cow feeding and geographic origin on milk using visible and near-infrared spectroscopy.

International audience; The ability of near-infrared spectroscopy to trace cow feeding systems and farming altitude was tested on 486 bulk milk samples from France and northwestern Italy. Milks were grouped into feeding systems according to the main forage in the diet. Partial least square discriminant analysis correctly classified 95.5, 91.5, and 93.3% of pasture versus maize silage, hay, and fermented herbage feeding systems, respectively. Discrimination was slightly less successful when diets with large proportions of the nondominant forage were included in each group. Near-infrared spectroscopy correctly discriminated no-pasture from pasture milk, even with only 30% of pasture in the diet (5.4% cross-validation error), and the error stabilized when pasture exceeded 70% (2.5% error). Near-infrared spectroscopy did not reliably trace milk geographic origin when the feeding system effect was isolated from the altitude effect. These findings may be usefully exploited for the authentication of dairy products

Mécanismes digestifs et métaboliques associés aux différences inter-individuelles de l’efficience alimentaire chez le bovin allaitant

Comprendre les mécanismes à l’origine des phénotypes d’intérêt en production animale est capital pour la sélection et l’alimentation des animaux. Dans le cadre du programme BEEFALIM 2020, qui visait à améliorer l’efficience alimentaire chez le bovin allaitant, plusieurs expériences ont été menées pour étudier les mécanismes digestifs et métaboliques associés aux variations individuelles de l’efficience alimentaire chez des jeunes bovins, génisses et vaches de race Charolaise. Pour évaluer les mécanismes digestifs et métaboliques impliqués, nous avons couplé des mesures directes à l’aide des méthodes de référence et des mesures indirectes à l’aide d’indicateurs (proxies et biomarqueurs). L’efficience alimentaire était caractérisée par la consommation moyenne journalière résiduelle, définie comme la partie de l’ingestion de matière sèche mesurée qui n’est pas expliquée par les performances animales observées (poids vif, gain de poids et composition du gain). Les résultats obtenus confirment que certains mécanismes d’ordre métabolique, ainsi que la composition corporelle des animaux, seraient associés de façon plus forte aux variations individuelles d’efficience alimentaire que les mécanismes d’ordre digestif, surtout lorsque les régimes sont riches en amidon. Un renouvellement des protéines tissulaires plus lent semble expliquer le meilleur taux de conversion de l’azote alimentaire en muscle chez les animaux efficients alimentés avec des régimes riches en amidon. Cependant, notre dispositif expérimental ne nous permet pas d’exclure la possibilité que l’appétit ou la capacité d’ingestion des animaux contribuent aux différences d’efficience alimentaire entre individus. En effet, les mécanismes identifiés pourraient être associés au phénotype efficient uniquement parce qu’ils covarient avec le niveau d’ingestion. D’après les résultats de cette étude et ceux de la littérature, il est suggéré néanmoins que le métabolisme et en particulier le renouvellement protéique seraient associés aux variations d’efficience alimentaire de manière indépendante du niveau d’ingestion. Ils constitueraient une première piste pour les considérer comme de vrais déterminants du phénotype d’efficience alimentaire. Des études complémentaires sont nécessaires pour établir le lien de causalité entre les mécanismes identifiés et l’efficience alimentaire

Detection of a Cis eQTL Controlling BMCO1 Gene Expression Leads to the Identification of a QTG for Chicken Breast Meat Color

Classical quantitative trait loci (QTL) analysis and gene expression QTL (eQTL) were combined to identify the causal gene (or QTG) underlying a highly significant QTL controlling the variation of breast meat color in a F2 cross between divergent high-growth (HG) and low-growth (LG) chicken lines. Within this meat quality QTL, BCMO1 (Accession number GenBank: AJ271386), encoding the β-carotene 15, 15′-monooxygenase, a key enzyme in the conversion of β-carotene into colorless retinal, was a good functional candidate. Analysis of the abundance of BCMO1 mRNA in breast muscle of the HG x LG F2 population allowed for the identification of a strong cis eQTL. Moreover, reevaluation of the color QTL taking BCMO1 mRNA levels as a covariate indicated that BCMO1 mRNA levels entirely explained the variations in meat color. Two fully-linked single nucleotide polymorphisms (SNP) located within the proximal promoter of BCMO1 gene were identified. Haplotype substitution resulted in a marked difference in BCMO1 promoter activity in vitro. The association study in the F2 population revealed a three-fold difference in BCMO1 expression leading to a difference of 1 standard deviation in yellow color between the homozygous birds at this haplotype. This difference in meat yellow color was fully consistent with the difference in carotenoid content (i.e. lutein and zeaxanthin) evidenced between the two alternative haplotypes. A significant association between the haplotype, the level of BCMO1 expression and the yellow color of the meat was also recovered in an unrelated commercial broiler population. The mutation could be of economic importance for poultry production by making possible a gene-assisted selection for color, a determining aspect of meat quality. Moreover, this natural genetic diversity constitutes a new model for the study of β-carotene metabolism which may act upon diverse biological processes as precursor of the vitamin A

Variations des teneurs en vitamines B dans le lait de vache selon l'alimentation

National audienc