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Poster De Conférence Année : 2017

Implication of the citrate ion in the fouling of falling-film evaporators during the concentration of acid wheys

Résumé

Vacuum evaporation is widely used in the dairy industry to concentrate the products before spray drying. The mineral fraction undergoes strong modifications and it is involved in the fouling of evaporator surface at increasing concentrations and temperature. In order to identify the composition of the fouling deposit, the behavior of the mineral fraction was studied during the concentration by evaporation of by-products of the manufacture of fresh cheeses and acid casein, lactic acid whey and hydrochloric acid whey respectively. These latter have the same pH (about 4.6) and are strongly mineralized, but differ from their mineral composition: lactic acid whey contains a high level of lactic acid but no citrate ion whereas hydrochloric acid whey contains citrate ion and no lactic acid. Concentration of both wheys was performed using a pilot-scale falling-film evaporator. Concentrates at different concentration factors (up to 6) were prepared and their mineral composition were determined experimentally. Total and soluble concentrations were compared to the theoretical values obtained by multiplying the concentration factor and the initial concentrations in the raw materials. The composition of the precipitates formed in the concentrates and on the evaporation tubes was then deduced. The behavior of the mineral fraction of both acid wheys during evaporation was shown very different. The concentration of lactic acid whey did not lead to the formation of mineral precipitate of calcium phosphate or other salts. On the contrary, precipitation of calcium citrate occurred into the concentrate during the concentration of hydrochloric acid whey. Moreover, losses of citrate and calcium in the concentrates were deduced, suggesting calcium citrate deposit on the surface of the evaporation tubes. This study underlines the key-role of citrate ion in the fouling of evaporators during the concentration of acid whey. The next steps are to recover the fouling deposit inside the evaporator to analyze directly the compositions and structure of salts formed.
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Dates et versions

hal-01608866 , version 1 (03-10-2017)

Identifiants

  • HAL Id : hal-01608866 , version 1
  • PRODINRA : 409151

Citer

Gaëlle Tanguy-Sai, Italo Tuler Perrone, Anne Dolivet, Anne-Cécile Santellani, Arlette Leduc, et al.. Implication of the citrate ion in the fouling of falling-film evaporators during the concentration of acid wheys. 3. International Symposium on Minerals & Dairy Products, Sep 2017, Wuxi, China. , 2017. ⟨hal-01608866⟩
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