Multiscale structures of lipids in foods as parameters affecting fatty acid bioavailability and lipid metabolism.

This review is respectfully dedicated to the memory of Michel Ollivon, Research Director at CNRS (Châtenay-Malabry, France), outstanding physico-chemist specialist of lipid organization, recipient of the Hilditch Memorial Lecture award, who was the initiator of the network RMT LISTRAL. We are also sadly paying tribute to Jean-Luc Vendeuvre, Food Engineer at the French Pork and Pig Institute (IFIP, Maisons-Alfort, France), outstanding expert in meat products who participated actively in RMT LISTRAL and provided unpublished data for figures in the present review, who passed away during review submission. RMT LISTRAL: Mixed Technological Network combining academic and industrial partners, devoted to the enhancement and divulgation of knowledge regarding structured dietary lipids.International audienceOn a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen

Short communication: Goat colostrum quality: Litter size and lactation number effects

The quality of colostrum of Murciano-Granadina goats was studied to establish the transition period and the time when milk can be marketed. Forty-three dairy goats were used: 19 primiparous (15 single births; 4 multiple births) and 24 multiparous (10 single births; 14 multiple births). Samples were collected every 12 h during the first week postpartum. Physicochemical parameters and somatic cell count were determined. Analysis of variance with repeated measures was used to study the effect of different factors: postpartum time, litter size, lactation number, their interactions, and production level on colostrum. Postpartum time had a significant effect on all parameters studied, which decreased along the first week of lactation, whereas lactose, pH, and conductivity increased. Based on these results, colostrum secretion takes place until 36 h postpartum (hpp). In relation to other factors of variation studied, the lactation number influenced most colostrum components, whereas the litter size only affected the pH value, protein and lactose content. The production level influenced only the protein and dry matter contents, with an inverse relationship. Milk produced during the period between 36 and 96 hpp is considered transition milk, which should not be commercialized. Milk collected after 4 d postpartum (96 hpp) could be marketed, ensuring that its composition does not present a risk in the dairy industry.This work was part of the AGL-2009-11524 Project funded by the Spanish Ministry of Science and Innovation (Madrid, Spain). The authors are grateful to ZEU-Inmunotec (Zaragoza, Spain) for their support.Romero Rueda, T.; Beltrán Martínez, MC.; Rodríguez Garcia, M.; Marti-De Olives A.; Molina Pons, MP. (2013). Short communication: Goat colostrum quality: Litter size and lactation number effects. Journal of Dairy Science. 96(12):7526-7531. https://doi.org/10.3168/jds.2013-6900S75267531961

Milk oligosaccharides: a review

Milk oligosaccharides (OSs) confer unique health benefits to the neonate. Although human digestive enzymes cannot degrade these sugars, they support specific commensal microbes and act as decoys to prevent the adhesion of pathogenic micro-organisms to gastrointestinal cells. The limited availability of human milk oligosaccharides (HMOs) impedes research into these molecules and their potential applications in functional food formulations. Recent studies show that complex OSs with fucose and N-acetyl neuraminic acid (key structural elements of HMO bioactivity) also exist in caprine milk, suggesting a potential source of bioactive milk OSs suitable as a functional food ingredient

Cas particulier des laits de chèvre et de brebis

National audienceSpecific cases of goat and sheep milks Small ruminants show specificities in terms of production of milk, protein and fat contents, and lipolysis levels, which are inherent in breeding systems, the number and size of animals, their genetic heritage, feeding and seasonality. Specific responses to feeding have been noticed especially on the profiles of fatty acids of nutritional interest (CLA, omega 3...). Nevertheless, whatever the answers, milk fat from small ruminants is characterized by significant levels of short-and medium-chain saturated fatty acids, with present nutritional and health benefits, and also different sizes of fat globules. The high polymorphism of the caprine s1 casein, which directly affects the protein content, also impacts the fat content, the size of fat globules and the lipolysis level. With regard to the use of milk from small ruminants, 98 % of the volume is turned into cheeses, most often without standardization of the fat. The fatty acid profiles from milk and cheese are thus similar implying that any improvement on the quality of the milk fat is directly transfered to the cheese. However, the specific technology, including storage, related to the seasonality can contribute to alter the nutritional and sensorial quality of fat (e.g. oxidation). The relationship between the structure of milk fat and its nutritional qualities is complex and constitute one of the most important current research thematic, especially when one takes into account the matrix effects on the bioavailability of the fat.Les petits ruminants présentent des particularités en terme de production de lait, de taux protéiques et butyreux et de niveaux de lipolyse, qui sont inhérentes aux modes de conduite d'élevage, à leur potentiel génétique, à l'alimentation et à la saisonnalité. Des réponses particulières à l'alimentation ont été enregistrées notamment sur les profils d'acides gras d'intérêt nutritionnel (CLA, omega 3...). Néanmoins, quelles que soient ces réponses, la matière grasse des laits de petits ruminants se caractérise par des teneurs importantes en acides gras saturés à courte et moyenne chaîne, présentant des bénéfices nutritionnels et santé et des tailles de globules gras très variables. Le fort polymorphisme de la caséine s1 caprine, qui influe directement sur les taux protéiques, a également un impact sur les taux de matière grasse, la taille des globules gras et les niveaux de lipolyse. Pour ce qui est de l'utilisation du lait de petits ruminants, 98 % de la production est transformé en fromage, la plupart du temps sans standardisation de la matière grasse. Les profils d'acides gras entre lait et fromage sont donc conservés et toute modification qualitative de la matière grasse du lait est directement répercutée sur les fromages. Néanmoins, des spécificités technologiques, de report notamment, liées à la saisonnalité peuvent contribuer à modifier la qualité de la matière grasse (l'oxydation notamment), nutritionnelle et sensorielle. La relation entre la structuration de la matière grasse laitière et ses qualités nutritionnelles est complexe et constitue une des pistes de recherche, en particulier avec la prise en compte des effets matrice sur la biodisponibilité de la matière grasse