Scudeller Luisa A, Blanpain-Avet Pascal, Six Thierry, Bellayer Séverine, Jimenez Maude, Croguennec Thomas, André Christophe, Delaplace Guillaume
UMR 8207-UMET-Unité Matériaux et Transformations, INRAE, CNRS, Univ. Lille, Centrale Lille, 59000 Lille, France.
Science et Technologie du lait et de l'oeuf (STLO)-UMR 1253, INRAE, Institut Agro, 35042 Rennes, France.
Foods. 2021 Jan 27;10(2):259. doi: 10.3390/foods10020259.
Fouling of plate heat exchangers (PHEs) is a recurring problem when pasteurizing whey protein solutions. As Ca is involved in denaturation/aggregation mechanisms of whey proteins, the use of calcium chelators seems to be a way to reduce the fouling of PHEs. Unfortunately, in depth studies investigating the changes of the whey protein fouling mechanism in the presence of calcium chelators are scarce. To improve our knowledge, reconstituted whey protein isolate (WPI) solutions were prepared with increasing amounts of phosphate, expressed in phosphorus (P). The fouling experiments were performed on a pilot-scale PHE, while monitoring the evolution of the pressure drop and heat transfer coefficient. The final deposit mass distribution and structure of the fouling layers were investigated, as well as the whey protein denaturation kinetics. Results suggest the existence of two different fouling mechanisms taking place, depending on the added P concentration in WPI solutions. For added P concentrations lower or equal to 20 mg/L, a spongy fouling layer consists of unfolded protein strands bound by available Ca. When the added P concentration is higher than 20 mg/L, a heterogeneously distributed fouling layer formed of calcium phosphate clusters covered by proteins in an arborescence structure is observed.
在对乳清蛋白溶液进行巴氏杀菌时，板式换热器（PHE）的结垢是一个反复出现的问题。由于钙参与了乳清蛋白的变性/聚集机制，使用钙螯合剂似乎是减少板式换热器结垢的一种方法。不幸的是，关于在钙螯合剂存在下乳清蛋白结垢机制变化的深入研究很少。为了增进我们的了解，制备了磷（P）含量不断增加的重组乳清蛋白分离物（WPI）溶液。在中试规模的板式换热器上进行结垢实验，同时监测压降和传热系数的变化。研究了污垢层的最终沉积质量分布和结构，以及乳清蛋白的变性动力学。结果表明，根据WPI溶液中添加的磷浓度，存在两种不同的结垢机制。当添加的磷浓度低于或等于20mg/L时，海绵状污垢层由被游离钙结合的未折叠蛋白链组成。当添加的磷浓度高于20mg/L时，会观察到由磷酸钙簇形成的、被呈树状结构的蛋白质覆盖的异质分布污垢层。
