Predicting the distribution of whey protein fouling in a plate heat exchanger using the kinetic parameters of the thermal denaturation reaction of β-lactoglobulin and the bulk temperature profiles

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Blanpain-Avet, Pascal | André, C. | Khaldi, Marwa | Bouvier, Laurent | Petit, J. | Six, Jacky | Jeantet, Romain | Croguennec, Thomas | Delaplace, Guillaume

Edité par HAL CCSD ; American Dairy Science Association

Fouling of plate heat exchangers (PHE) is a severe problem in the dairy industry, notably because therelationship between the build-up of protein fouling deposits and the chemical reactions taking place inthe fouling solution has not yet been fully elucidated. Experiments were conducted at pilot scale in a corrugatedPHE, and fouling deposits were generated using a model β-lactoglobulin (β-LG) fouling solution for whichthe β-LG thermal denaturation reaction constants had been previously determined experimentally. Then 18different bulk temperature profiles within the PHE were imposed. Analysis of the fouling runs shows thatthe dry deposit mass per channel versus the ratio R = kunf/kagg (with kunf and kagg representing, respectively,the unfolding and aggregation rate constants computed from both the identification of the β-LG thermal denaturation process and knowledge of the imposed bulk temperature profile into the PHE channel) is able togather reasonably well the experimental fouling mass data into a unique master curve. This type of representation of the results clearly shows that the heat-induced reactions (unfolding and aggregation) of the various β-LG molecular species in the bulk fluid are essential to capture the trend of the fouling mass distribution inside a PHE. This investigation also illustrates unambiguously that the release of the unfolded β-LG (also called β-LG molten globule) within the bulk fluid (and the absence of its consumption in the form of aggregates) is a key phenomenon that controls the extent of protein fouling as well as its location inside the PHE.

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