Structural and compositional changes during UHT fouling removal—Possible mechanisms of the cleaning processShow others and affiliations
2019 (English)In: Food Structure, ISSN 2213-3291, Vol. 21, article id 100118Article in journal (Refereed) Published
Abstract [en]
Ultra-high temperature (UHT) treatment of milk forms a deposit or fouling in the processing equipment that is mineral-based with an enclosed protein network. This study addresses the fundamental mechanisms that control the removal of this deposit. For this purpose, the structural and compositional changes during the cleaning process have been studied. The structure analysis was performed with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) on samples that were quenched at different stages of the cleaning process. It was found for acid cleaning that the mineral content is rapidly decreasing in the fouling layer as the cleaning continues, but there is still an intact protein structure with the similar thickness as the original fouling. For alkali cleaning, part of the protein structure was subsequently removed from the outside towards the stain-less steel as a function of time, while the mineral structure was mostly remaining. The break-up of the organic network structure, which likely involves depolymerization of protein aggregates, were found to control the cleaning efficiency. The weakening of the protein network facilitates the removal of the UHT fouling layer during the acid cleaning step and allow for an efficient cleaning cycle. The chemical reactions that occur within the fouling layer between the hydroxyl ions and the protein network was modeled according to a depolymerization reaction and a mechanistic model of the cleaning process is presented. © 2019
Place, publisher, year, edition, pages
Elsevier Ltd , 2019. Vol. 21, article id 100118
Keywords [en]
Cleaning, Fouling structure, Mechanistic model, Milk fouling, Mineral deposit, Protein depolymerization, Protein net-work
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-39449DOI: 10.1016/j.foostr.2019.100118Scopus ID: 2-s2.0-85067823105OAI: oai:DiVA.org:ri-39449DiVA, id: diva2:1335989
Note
Funding details: Svenska Forskningsrådet Formas; Funding text 1: We acknowledge the financial support of TvärLivs , which is a cooperative venture between The Swedish Research Council Formas, The Swedish Farmers Foundation for Agricultural Research (SLF), the Swedish Governmental Agency for Innovation Systems Vinnova, Livsmedelsföretagen, and Svensk Dagligvaruhandel, as well as Tetra Pak Processing Systems and Arla Foods. Appendix A
2019-07-082019-07-082023-10-06Bibliographically approved