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Rangées de graines.. © INRA, Elena Schweitzer © Fotolia

Our results

  1. Introduction
  2. Human milk digestion in the preterm infant: impact of technological treatments
  3. Research & Innovation 2017 - For Food and Biobased Products
  4. The way in which proteins aggregate when heated may change their sensitising potency
  5. Enhancing the viability of spray-dried probiotic bacteria by stimulating their stress tolerance
  6. To stick or not to stick? Pulling pili sheds new light on biofilm formation
  7. When biopolymers selfassemble: a balance between energy and entropy.
  8. Mimicking the gastrointestinal digestion in a lab-on-a-chip:the microdigester
  9. How a milk droplet becomes a powder grain
  10. Research & Innovation 2016 - For Food and Bioproducts
  11. A new process for the biorefining of plants
  12. Under the UV light : the bacterial membrane
  13. Reverse engineering or how to rebuild ... bread!
  14. Green Chemistry: a step towards lipid production in yeast
  15. Individually designed neo-enzymes for antibacterial vaccines
  16. Multi-scale mechanical modelling: from the nanometric scale to the macroscopic properties of bread crumb
  17. Minimill: 500 g to assess the milling value of soft wheats
  18. Microbial production of lipids for energy or chemical purposes
  19. The discrete role of ferulic acid in the assembly of lignified cell wall
  20. Eco-design of composites made from wood co-products
  21. Analysis of volatile compounds enables the authentication of a poultry production system
  22. Nanoparticles as capping agents for biopolymers microscopy
  23. Pasteurisation, UHT, microfiltration...All the processes don't affect the nutritional quality of milk in the same way
  24. Integration of expert knowledge applied to cheese ripening
  25. Controlling cheese mass loss during ripening
  26. The shape memory of starch
  27. Research & Innovation 2015 - For Food & Biobased Products
  28. Behaviour of casein micelles during milk filtering operations
  29. Overaccumulation of lipids by the yeast S. cerevisiae for the production of biokerosine
  30. Sequential ventilation in cheese ripening rooms: 50% electrical energy savings
  31. An innovative process to extract bioactive compounds from wheat
  32. Diffusion weighted MRI: a generic tool for the microimaging of lipids in food matrices
  33. Characterization of a major gene of anthocyanin biosynthesis in grape berry
  34. New enzyme activity detectors made from semi-reflective biopolymer nanolayers
  35. Improving our knowledge about the structure of the casein micelle
  36. Heating milk seems to favour the development of allergy in infants
  37. Fun with Shape
  38. Using volatile metabolites in meat products to detect livestock contamination by environmental micropollutants
  39. SensinMouth, when taste makes sense
  40. A decision support system for the fresh fruit and vegetable chain based on a knowledge engineering approach
  41. SOLEIL casts light on the 3D structure of proteins responsible for the stabilisation of storage lipids in oilseed plants
  42. A close-up view of the multi-scale protein assembly process
  43. Controlling the drying of infant dairy products by taking water-constituent interactions into account
  44. Polysccharide nanocrystals to stabilise pickering emulsions
  45. Discovery of new degradative enzymes of plant polysaccharides in the human intestinal microbiome
  46. A durum wheat flour adapted for the production of traditional baguettes
  47. Virtual modelling to guide the construction of « tailored-made » enzymes
  48. How far can we reduce the salt content of cooked meat products?
  49. Diffusion of organic substances in polymer materials: beyond existing scaling laws
  50. Smart Foams : various ways to destroy foams on demand !
  51. Dates, rich in tannins and yet neither bitter nor astringent
  52. Sodium content reduction in food
  53. Research & Innovation 2014

Pasteurisation, UHT, microfiltration...All the processes don't affect the nutritional quality of milk in the same way

Heat treatments applied to milk provide the consumer with somewhat long-term stability, but their effect on protein quality is often compromised. Despite this, their impact has never been measured in vivo in humans, though, in France, UHT milk accounts for 90% of milk consumption...

Cruche et verre de lait UHT normalisé demi écrémé.. © INRA, BOSSENNEC Jean-Marie

Pasteurised or UHT Milks : the heat treatments may affect the nutritional quality of proteins

Milk is mainly consumed in its pasteurised form in industrial countries, but in some European countries such as France, UHT milk accounts for 90% of milk consumption.
Microfiltration was recently developed as a microbiological stabilisation treatment that does not denature the organoleptic qualities of milk.  The protein fraction constitutes a major nutritional benefit of milk, along with calcium.  However, heat treatments can lead to structural modifications that are well recognised at this time and that may affect the nutritional quality of proteins.  These modifications can, for example, induce a loss of certain amino acids or the formation of neoformed protein aggregates (Léonil et al., 1997; Guyomarc et al., 2003).
Nevertheless, no data exists today that enable us to quantify these structural alterations during treatment in humans.

The digestive tract of milk proteins monitored on healthy volunteers

Healthy volunteers (n = 24) drank the equivalent of a half litre of microfiltred, pasteurised or UHT milk.  The milk proteins were intrinsically marked beforehand with 15N nitrogen.  This stable isotope, thus representative of milk proteins, was monitored in different nitrogen pools (urea, amino acids and plasma proteins, urinary urea) for 8 h after the meal. 15N nitrogen found in urea is considered to be irreversibly lost and therefore not retained by the organism.
We show that the kinetics and the 15N nitrogen transfer balance in nitrogen pools are identical between pasteurisation and microfiltration, indicative of a similar metabolic utilisation of the milk proteins.  In contrast, an increase in the transfer of 15N nitrogen in all of the nitrogen pools studied was observed for the UHT milk, resulting in an increase of 7% in food nitrogen losses in the urea.  However, we also observed that the incorporation of food nitrogen into plasma proteins is increased in UHT milk, evidence of the good capacity of food amino acids to sustain protein syntheses.  As a result, the most plausible hypothesis to explain the increase of irreversible losses of food nitrogen in the case of UHT milk is an acceleration of the gastric emptying kinetics and not a biochemical modification of the proteins.  The acceleration of digestive kinetics is a major factor in the stimulation of food amino acid catabolism.
The hypothesis of an acceleration of the kinetics of UHT milk proteins is most certainly linked to the fact that the UHT treatment leads to a greater particle scattering of casein micelles due to the formation of soluble aggregates induced by heat and less apt to precipitate in the stomach.

How to preserve the nutritional quality of proteins ?

The nutritional quality of proteins in UHT milk could therefore be preserved by modulating their gastric emptying speed, thus emphasizing the need to study food digestion mechanisms, a project to be carried out in partnership with nutritionists from INRA’s Nutrition, Chemical Food Safety and Consumer Behaviour division.

A partnership between Biochemists, Physico-chemists, Nutritionists and the dairy sector

This work is part of an integrated project between the division for Science and Process Engineering of Agricultural Product and the division for Nutrition, Chemical Food Safety and Consumer Behaviour. It has been funded by the Ministry of Research and the dairy sector, Arilait Recherches

See also

  • Lacroix M, Bon C, Bos C, Léonil J, Benamouzig R, Luengo C, Fauquant J, Tomé D, Gaudichon C. Ultra high temperature treatment, but not pasteurization, affects the postprandial kinetics of milk proteins in humans. J Nutr. 2008 ;138(12):2342-7