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Characterisation of whey protein isolate–gum tragacanth electrostatic interactions in aqueous solutions
Author(s) -
Raoufi Nassim,
Kadkhodaee Rassoul,
Phillips Glyn O.,
Fang Yapeng,
Najafi Masoud Najaf
Publication year - 2016
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.13088
Subject(s) - tragacanth , biopolymer , chemistry , dispersity , aqueous solution , whey protein isolate , yield (engineering) , chromatography , whey protein , gum arabic , zeta potential , chemical engineering , polymer chemistry , materials science , organic chemistry , food science , polymer , metallurgy , nanoparticle , engineering
Summary The main objectives of this study were to measure molecular parameters of gum tragacanth by GPC ‐ MALLS system and investigate the complexation behaviour of whey protein isolate/gum tragacanth mixed dispersions (0.5 wt% total biopolymer concentration) as a function of pH (7.00–2.00) and the biopolymer mixing ratio ( r = 0.1–10) using spectrophotometric, zeta potential and precipitate yield determination methods. GPC ‐ MALLS revealed that gum tragacanth contains relatively heterogeneous particles with high weight‐average and number‐average ( M w = 7.74 × 10 5 g mol −1 and M n = 3.87 × 10 5 g mol −1 ) molecular mass and high dispersity index (~2.04 ± 0.3). Results of complexation displayed that as the biopolymer mixing ratio increases, the net neutrality shifts to the higher pH s. The critical values associated with the complex structure formation were found at r = 2 in which the charge density of the mixture was near zero at a wide range of pH (3.0–4.0). However, the highest precipitate yield achieved in pH 3.4.