On the nature of the optimum cleaning concentration for dairy fouling: High NaOH concentrations inhibit the cleavage of non-covalent interactions in whey protein aggregates

Liyuan Fan, Xiao Dong Chen, Ruben Mercadé-Prieto

Research output: Indexed journal article Articlepeer-review

10 Citations (Scopus)

Abstract

The dairy industry has long known that highly concentrated alkaline solutions should not be used to clean whey protein rich fouling deposits. At >0.1 mol L−1 NaOH dissolution and cleaning rates decrease markedly to very low values, particularly at low-mid temperatures. It is shown here that it is caused by the incapacity of the hydroxide ion to destroy non-covalent interactions between protein aggregates at high alkali concentrations. HPLC is used to quantify the breakdown kinetics of soluble whey protein isolate (WPI) aggregates. Results show that the large aggregates breakdown kinetic constant is strongly reduced at >0.25 mol L−1 NaOH, but also at high protein concentrations. Moreover, large aggregates become increasingly stable for long times at ≥0.5 mol L−1 NaOH. The kinetic analysis predicts that large protein aggregates would be fully stable at 0.085–0.105 g WPI/g solution, explaining the dissolution threshold observed in macroscopic swelling studies.

Original languageEnglish
Pages (from-to)519-525
Number of pages7
JournalLWT
Volume101
DOIs
Publication statusPublished - Mar 2019
Externally publishedYes

Keywords

  • Cleaning-in-place
  • Dissolution
  • HPLC
  • Protein aggregation

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