Characterization of pea vicilin. 2. Consequences of compositional heterogeneity on heat-induced gelation behavior.
The gelling characteristics of two vicilin fractions from pea (Pisum sativum L.) were compared over a range of pH and salt conditions after preliminary results showed that despite having equal opportunity to unfold, and expose hydrophobic residues, they had different minimum gelling concentrations (at pH 7.6). Furthermore, at this pH one fraction formed turbid gels and the other formed transparent gels. The fraction that formed transparent gels contained a substantial amount of the 70 kDa alpha-subunits of vicilin, and thus it was hypothesized that the highly charged N-terminal extension region on these 70 kDa subunits hinders gelation of this vicilin fraction at pH 7.6 and I = 0.2 due to repulsion of the net negative charge. The experiments designed to test this hypothesis are presented and discussed in this paper and prove that the hypothesis was true, which offers the possibility to control or modify the gelation behavior of vicilin on the basis of information of its subunit composition.
O'Kane
Francesca E
FE
Product Design and Quality Management Group, Centre for Protein Technology TNO-WU, and Laboratory of Food Chemistry, Wageningen University, Wageningen, The Netherlands.
Happe
Randolph P
RP
Vereijken
Johan M
JM
Gruppen
Harry
H
van Boekel
Martinus A J S
MA
D005782:Gels / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D018532:Pisum sativum / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D017510:Protein Folding; D055314:Seed Storage Proteins; D012965:Sodium Chloride / Q000494:pharmacology
D005782:Gels; D010940:Plant Proteins; D055314:Seed Storage Proteins; D012965:Sodium Chloride; C015575:vicilin protein, plant