Effect of pH on turbidity, size, viscosity and the shape of sodium caseinate aggregates with light scattering and rheometry

Sara Ghorbani Gorji, Elham Ghorbani Gorji, Mohammad Amin Mohammadifar

Research output: Contribution to journalJournal articleResearchpeer-review


The characterization of sodium caseinate solutions as a function of pH was determined using titration with HCL through turbidimetry in different concentrations (0.03 wt.%, 0.045 wt.%, 0.06 wt.%, 0.09 wt.%, 0.2 wt.%, and 0.3 wt.%). Additionally, the coupling of slow in situ acidification of the solution and rheometry was utilized to gain deeper insights into pH-induced structural transitions during the self assembly process and particle size distribution analysis have been used to determine the behavior of sodium caseinate solutions in different pHs. The formation of aggregates during the acidification process was clearly visualized using microscopy. Surprisingly the viscosity of sodium caseinate solution at pH 4.64 was maximum and decreased by lowering pH. Particle size analysis confirmed the onset of big aggregates on decreasing pH but further acidification led to formation of smaller aggregates. A small concentration effect on pI was seen where at sodium caseinate levels of 0.03 wt.% the pI occurred at 4.29, where at sodium caseinate levels of 0.30 wt.% pI value was 4.64.
Original languageEnglish
JournalJournal of Food Science and Technology
Issue number3
Pages (from-to)1820-1824
Number of pages5
Publication statusPublished - 2015
Externally publishedYes


  • Food Science
  • Aggregation
  • Particle size
  • Sodium caseinate
  • Spectrophotometry
  • Viscosity
  • Acidification
  • Aggregates
  • Light scattering
  • Particle size analysis
  • Rheometers
  • Self assembly
  • Sodium
  • Effect of pH
  • Particle size distribution analysis
  • pI values
  • Rheometry
  • Self assembly process
  • Small concentration
  • Structural transitions
  • Agglomeration
  • Chemistry
  • Nutrition
  • Chemistry/Food Science, general
  • Chemistry and Materials Science
  • food viscosity
  • structural transition
  • hydrochloric acid 7647-01-0
  • sodium caseinate
  • 10060, Biochemistry studies - General
  • 10511, Biophysics - Bioengineering
  • 13502, Food technology - General and methods
  • in situ acidification method laboratory techniques
  • light scattering laboratory techniques, spectrum analysis techniques
  • microscopy laboratory techniques, imaging and microscopy techniques
  • particle size distribution analysis laboratory techniques
  • rheometry laboratory techniques
  • self assembly process laboratory techniques
  • spectrophotometry laboratory techniques, spectrum analysis techniques
  • turbidimetry laboratory techniques
  • Biomaterials
  • Foods
  • Methods and Techniques
  • Food sciences
  • Physics and biophysics


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