How does the structure of dairy products affect their digestion mechanisms? Consequences on human health

Didier Dupont (1)

1 STLO - Science et Technologie du Lait et de l'Oeuf

Digestion provides nutrients and energy essential to the survival and growth of the organisms. But little is known about the influence of food structure and of interactions between food components during processing on their digestibility and nutritional properties. Our objectives are to understand how dairy products are disintegrated in the gastrointestinal tract, identify the potentially bioactive molecules (peptides, amino acid, fatty acid...) released during digestion and demonstrate the physiological effect of these molecules on the host. In a first experiment, six dairy matrices (raw and heat - treated milk, stirred and non - stirred acid gels, rennet gels made of raw or heat - treated milk) of similar composition but with different micro and macrostructures were manufactured in a pilot plant. Each sample was given to six multi- canulated adult mini- pigs. Effluents were collected in the duodenum and mid-jejunum during 7h after the meal and characterized by SDS-PAGE, LC -MS-MS and ELISA. Free amino acids were quantified in plasmas. More than 16000 peptides released in the lumen during digested were identified. Among those, several are known for carrying biological activities. Compares to liquid milks, acid gels showed a delayed gastricemptying and a slower release of caseins and β-lactoglobulin in the duodenum. In a secondexperiment, two infant formulas adapted to reac h the nutritional requirement of piglets were manufactured using either vegetable fat (STD) or a combination of milk and vegetable fats stabilized by a mixture of proteins and milk fat globule membrane fragments (EXP). The formulas were distributed with an automatic milk feeder to piglets until slaughter at 28 days. Intestinal contents and tissues as well as mesenteric lymph nodes (MLN) were collected. Microbiota diversity and composition was assessed using DHPLC and metasequencing analysis. The immunoreact ivity of β-lg and Cns, as determined by ELISA, was higher in EXP than in STD intestinal contents. The secretory activity of MLN cells was modified by the formula composition, the highest IFNγ secretion was obtained in EXP piglets. Microbiota clustering successfully discriminated infant formulas according to the nature of fat. Differences in proteobacteria and firmicutes phyla were observed. These data emphasize the crucial role played by the food composition but also its structure on the digestion mechanisms, the kinetics of nutrient release and the physiological response of the host

Mots clés: produit laitier; structure des aliments; santé humaine; digestion

Domaines: Ingénierie des aliments; Alimentation et Nutrition

Didier Dupont. How does the structure of dairy products affect their digestion mechanisms? Consequences on human health. Health promotion and disease prevention of functionnal foods, nutraceucals and naturals health products, Jun 2014, Kocaeli, Turkey. ⟨hal-01209681⟩