title: Effect of chitosan on the heat stability of whey protein solution as a function of pH.
abstract: BACKGROUND
  Chitosan was reported to interact with proteins through electrostatic interactions. Their interaction was influenced by pH, which was not fully characterized. Further research on the interactions between protein and chitosan at different pH and their influence on the thermal denaturation of proteins is necessary.
  
  
  RESULTS
  In this research, the effect of chitosan on the heat stability of whey protein solution at pH 4.0-6.0 was studied. At pH 4.0, a small amount chitosan was able to prevent the heat-induced denaturation and aggregation of whey protein molecules. At higher pH values (5.5 and 6.0), whey proteins complexed with chitosan through electrostatic attraction. The formation of chitosan-whey protein complexes at pH 5.5 improved the heat stability of dispersions and no precipitation could be detected up to 20 days. The dispersion with a medium amount of chitosan (chitosan:whey protein 1:5) produced the most stable particles, which had an average radius of 135 ± 14 nm and a zeta potential value of 36 ± 1 mV. In contrast, at pH 6.0 only the dispersion with a high amount of chitosan (chitosan:whey protein 1:2) showed good shelf stability up to 20 days.
  
  
  CONCLUSIONS
  It was possible to produce heat-stable whey protein beverages by regulating the interaction between chitosan and whey protein molecules. © 2016 Society of Chemical Industry.
authors.affiliation: Department of Food Science, University of Guelph, Guelph, Ontario N1G2W1, Canada.
authors.forename: Zhengtao
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: School of Food Science and Technology, Hunan Agricultural University, Hunan 410128, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xiao
mesh_terms: D001628:Beverages; D011232:Chemical Precipitation; D048271:Chitosan / Q000737:chemistry*; D005511:Food Handling; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D055672:Static Electricity; D000067816:Whey Proteins / Q000737:chemistry*
chemical_list: D000067816:Whey Proteins; D048271:Chitosan
keywords: chitosan; particle size distribution; turbidity; whey protein; zeta potential