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Aims: This study describes the different stages of optimization in an original drying process for yeasts, which allows the retrieval of dried samples of Saccharomyces cerevisiae CBS 1171 with maximum viability. Methods and Results: The process involves the addition of wheat flour to yeast pellets, followed by mixing and then air-drying in a fluidized bed dryer. The sensitivity to the osmotic stress was first studied in a water-glycerol solution and the observed results were then applied to the drying process. This study have shown that the yeast was quite resistant to osmotic stress and pointed out the existence of zones of sensitivity where viability dramatically decrease as function of final osmotic pressure and temperature of the treatment. Thus, for dehydration until low osmotic pressure (133 MPa, i.e. a w ¼ 0AE38) results have shown that viability was better when temperature of the treatment was less than 8°C or higher than 25°C. Moreover, kinetic of dehydration was found to greatly influence cells recovery. Conclusions: These observations allowed the choice of parameters of dehydration of yeasts with an original drying process which involve the mix of the yeasts with wheat flour and then drying in a fluidized bed. Significance and Impact of the Study: This process dried rapidly the yeasts to less than 220 MPa (aw £ 0AE2) with whole cell recovery and good fermentative capabilities.

Hydrophilisation of polyethersulfone (PES) based membrane is often achieved by addition of polyvinylpyrrolidone (PVP) leading to a physical blend of the two polymers. This paper shows that the most commonly used membrane for UF in dairy industry is a PES/PVP based one. Nevertheless if hydrophilisation limits the organic fouling, PVP is also the Achilles heel of these membranes. It is particularly true when membranes are exposed to hypochlorite as it is the case for cleaning/disinfection steps. Evidencing the disappearance of PVP from a pristine PES/PVP membrane can be easily achieved by FTIR-ATR analyses. But when one wants to study the ageing of a membrane used in UF it gets more complicated: regardless of the cleaning efficiency the membrane always remains fouled by some proteins. As both PVP and proteins own chemical bounds leading to absorption at the same wavenumber in FTIR-ATR, it thereby prevents the easy highlighting of the PVP degradation. The aim of this paper is to propose a simple treatment of raw FTIR-ATR spectra to dissociate these two contributions, allowing consequently the study of the degradation of a fouled membrane. Then the procedure is applied to a real case study on a spiral membrane. 2 1. Highlights Ͳ Ͳ Ğ|ŝĚĞŶĐŝŶŐ W^ͬWsW ŵĞŵďƌĂŶĞ ĚĞŐƌĂĚĂƚŝŽŶ ďLJ &d/Z ĚĞƐƉŝƚĞƐ ƉƌĞƐĞŶĐĞ ŽĨ ƉƌŽƚĞŝŶ ĨŽƵůŝŶŐ Ͳ Ͳ Ͳ ŵĞƚŚŽĚŽůŽŐLJ ŽĨ ƚƌĞĂƚŵĞŶƚ ŽĨ &d/Z ƐƉĞĐƚƌĂ ƚŽ ƌĞ|ĞĂů ŵĞŵďƌĂŶĞ ĚĞŐƌĂĚĂƚŝŽŶ ĚƵĞ ƚŽ EĂKů Ͳ Ͳ Ͳ ĂƉƉůŝĐĂƚŝŽŶ ƚŽ ŵĂƉƉŝŶŐ ŽĨ WsW ĚĞŐƌĂĚĂƚŝŽŶ ĚƵĞ ƚŽ EĂKů ŝŶ Ă ƐƉŝƌĂů ŵĞŵďƌĂŶĞ Ͳ Ͳ Ͳ ĂƉƉůŝĐĂƚŝŽŶ ƚŽ ŵĂƉƉŝŶŐ ŽĨ W^ ĚĞŐƌĂĚĂƚŝŽŶ ĚƵĞ ƚŽ EĂKů ŝŶ Ă ƐƉŝƌĂů ŵĞŵďƌĂŶĞ

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