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

Our results

  1. Introduction
  2. Research and Innovation 2018 - For Food and Biobased Products
  3. Dry-cured ham: a process simulator can now define routes of manufacture that yield lower-salt 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. Human milk digestion in the preterm infant: impact of technological treatments
  7. Research & Innovation 2017 - For Food and Biobased Products
  8. To stick or not to stick? Pulling pili sheds new light on biofilm formation
  9. When biopolymers selfassemble: a balance between energy and entropy.
  10. Mimicking the gastrointestinal digestion in a lab-on-a-chip:the microdigester
  11. How a milk droplet becomes a powder grain
  12. Research & Innovation 2016 - For Food and Bioproducts
  13. A new process for the biorefining of plants
  14. Under the UV light : the bacterial membrane
  15. Reverse engineering or how to rebuild ... bread!
  16. Green Chemistry: a step towards lipid production in yeast
  17. Individually designed neo-enzymes for antibacterial vaccines
  18. Multi-scale mechanical modelling: from the nanometric scale to the macroscopic properties of bread crumb
  19. Minimill: 500 g to assess the milling value of soft wheats
  20. Microbial production of lipids for energy or chemical purposes
  21. The discrete role of ferulic acid in the assembly of lignified cell wall
  22. Eco-design of composites made from wood co-products
  23. Analysis of volatile compounds enables the authentication of a poultry production system
  24. Nanoparticles as capping agents for biopolymers microscopy
  25. Pasteurisation, UHT, microfiltration...All the processes don't affect the nutritional quality of milk in the same way
  26. Integration of expert knowledge applied to cheese ripening
  27. Controlling cheese mass loss during ripening
  28. The shape memory of starch
  29. Research & Innovation 2015 - For Food & Biobased Products
  30. Behaviour of casein micelles during milk filtering operations
  31. Overaccumulation of lipids by the yeast S. cerevisiae for the production of biokerosine
  32. Sequential ventilation in cheese ripening rooms: 50% electrical energy savings
  33. An innovative process to extract bioactive compounds from wheat
  34. Diffusion weighted MRI: a generic tool for the microimaging of lipids in food matrices
  35. Characterization of a major gene of anthocyanin biosynthesis in grape berry
  36. New enzyme activity detectors made from semi-reflective biopolymer nanolayers
  37. Improving our knowledge about the structure of the casein micelle
  38. Heating milk seems to favour the development of allergy in infants
  39. Fun with Shape
  40. Using volatile metabolites in meat products to detect livestock contamination by environmental micropollutants
  41. SensinMouth, when taste makes sense
  42. A decision support system for the fresh fruit and vegetable chain based on a knowledge engineering approach
  43. SOLEIL casts light on the 3D structure of proteins responsible for the stabilisation of storage lipids in oilseed plants
  44. A close-up view of the multi-scale protein assembly process
  45. Controlling the drying of infant dairy products by taking water-constituent interactions into account
  46. Polysccharide nanocrystals to stabilise pickering emulsions
  47. Discovery of new degradative enzymes of plant polysaccharides in the human intestinal microbiome
  48. A durum wheat flour adapted for the production of traditional baguettes
  49. Virtual modelling to guide the construction of « tailored-made » enzymes
  50. How far can we reduce the salt content of cooked meat products?
  51. Diffusion of organic substances in polymer materials: beyond existing scaling laws
  52. Smart Foams : various ways to destroy foams on demand !
  53. Dates, rich in tannins and yet neither bitter nor astringent
  54. Sodium content reduction in food
  55. Research & Innovation 2014

Enhancing the viability of spray-dried probiotic bacteria by stimulating their stress tolerance

The World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) officially defined probiotics as "live microorganisms which when ingested in adequate amounts confer a health benefit to the host. Although they are generally associated with dairy products, they are found today in a wide variety of human foods and animal feeds. Probiotics are therefore beneficial health bacteria found in various foods and feed products.

Updated on 04/19/2017
Published on 04/19/2017

However, their manufacture requires production and storage processes that are likely to alter the structural and functional integrity of cells. Freeze-drying, which acts through a combination of cold and vacuum, is the most widely used drying method to preserve bacteria, although it is energy-intensive. Alternatives such as atomisation and fluidisation cost less but they involve the use of hot air, leading to viability and functionality losses.

Bactérie Propionibacterium freudenreichii cultivée sur lactosérum concentré à 30% (p/p) d’extrait sec et colorée au DAPI avant observation au microscope à épifluorescence. La fluorescence bleue indique la présence d’ADN. La fluorescence verte celle de polyphosphate, un composé minéral accumulé par cette bactérie comme source d’énergie et contribuant à son osmoadaptation.. © INRA
Bactérie Propionibacterium freudenreichii cultivée sur lactosérum concentré à 30% (p/p) d’extrait sec et colorée au DAPI avant observation au microscope à épifluorescence. La fluorescence bleue indique la présence d’ADN. La fluorescence verte celle de polyphosphate, un composé minéral accumulé par cette bactérie comme source d’énergie et contribuant à son osmoadaptation. © INRA

We designed a simplified and energy-efficient process that maintained bacteria viability close to that of freeze-drying. Unlike the regular process that requires an initial culture stage for the microorganism on an optimum medium (frequently, non-food grade), followed by rinsing and re-suspension in a new medium before dehydration, the new process consists of direct spray-drying of the culture medium. In addition to a gain in productivity, this simplification eliminates risks of contamination at the intermediate stages. Challenged on two probiotic strains, one fragile (Lactobacillus casei) and the other robust (Propionibacterium freudenreichii), this process has demonstrated an efficiency comparable to that of freeze-drying, with respective survival rates of around 40-50% and 100%. The nutrient medium developed utilises whey, a by-product of the cheese-making industry, which is abundant and inexpensive. The dry matter concentration of this medium, in the range of20 to 30% (w/w) dry matter, has been optimised in order to protect bacterial cells during atomisation. Indeed, we showed thathyperconcentrated sweet whey as a culture medium led to bacteria osmoadaptation through the accumulation of compatible solutes (trehalose, polyphosphate), triggering multistress tolerance and enhanced survival upon spray-drying.The stability of microorganisms over time has also been verified at 4 and 6 months, with results comparable to those of freeze-drying.


This innovative process makes it possible to produce dry probiotics in a continuous mode and at 20 to 40 times lower energy costs than freeze-drying, given the lower specific energy consumption of spray-drying and the pre-concentration of the growth medium.This patented process appears to be particularly well suited to producing probiotics for animal feeds. Probiotics could thus offer an alternative to antibiotic therapy and constitute an efficient, ethical, economical and sustainable response to the issues of profitability and animal health.The food sector could also provide the opportunity to mass produce probiotics intended for everyday consumer use.


Huang S, Cauty C, Dolivet A, Le Loir Y, Chen XD, Schuck P, Jan G, Jeantet R.2016. Double use of highly concentrated sweet whey to improve the biomass production and viability of spray-dried probiotic bacteria. J Funct Foods, 23, 455-463 DOI: 10.1016/j.jff.2016.02.050

Huang S, Rabah H, Jardin J, Briard-Bion V, Parayre S, Maillard MB, Le Loir Y, Chen XD, Schuck P, Jeantet R, Jan G.2016. Hyperconcentrated sweet whey, a new culture medium that enhancesPropionibacterium freudenreichiistress tolerance. Applied Env Microbiol, 82, 4641-4651 DOI: 10.1128/AEM.00748-16

Institut National de la Recherche Agronomique, Institut supérieur des Sciences Agronomiques, Agroalimentaires, Horticoles et du Paysage.2015. Method for preparing a probiotic powder using a two-in-one whey-containing nutrient medium. Demande de brevet déposée en Europe le 21 septembre 2015 sous le n° EP 15 306465.4. Inventeurs : Jeantet R, Huang S, Jan G, Schuck P, Le Loir Y, Chen XD.



Science and Technology of Milk and Eggs research unit http://www6.rennes.inra.fr/stlo_eng/

Joint Research Unit INRA and Food and Agricultural Science University (AGROCAMPUS OUEST)

Romain Jeantet - Romain.Jeantet@agrocampus-ouest.fr

Gwénaël Jan - Gwenael.Jan@inra.fr