Complex coacervation of pea albumin-pectin and ovalbumin-pectin assessed by isothermal titration calorimeter and turbidimetry

J Sci Food Agric. 2021 Feb;101(3):1209-1217. doi: 10.1002/jsfa.10733. Epub 2020 Sep 3.

Abstract

Background: This study investigates the complexation of a pea albumin-rich fraction and ovalbumin with pectin of different degrees of esterification (DE) and blockiness (DB) as a function of pH and biopolymer mixing ratio by turbidimetric titration and isothermal titration calorimetry (ITC).

Results: Turbidimetric analysis found maximum complexation occurred at a mixing ratio of 4:1 for pea albumin with high methoxy pectin, 8:1 for pea albumin with low methoxy pectin, and 8:1 for ovalbumin with low methoxy pectin. In the case of ovalbumin with high methoxy pectin, interactions were very weak. The pectin with high levels of esterification and blockiness displayed greater interactions with the pea albumin in both turbidimetry and ITC. However, low methoxy pectin imparted better interactions with ovalbumin and displayed higher optical density values than high methoxy pectin.

Conclusions: The current study indicated that the different thermodynamic parameters of PA-pectin complexes can be tuned by controlling the structural characteristics (DB, DE, and d-galacturonic acid) of the pectin. © 2020 Society of Chemical Industry.

Keywords: coacervates; complexation; pea protein; pectin; thermodynamic parameters; water soluble fractions.

MeSH terms

  • Albumins / chemistry*
  • Biopolymers / chemistry
  • Calorimetry
  • Nephelometry and Turbidimetry / instrumentation
  • Nephelometry and Turbidimetry / methods*
  • Ovalbumin / chemistry*
  • Pectins / chemistry*
  • Pisum sativum / chemistry*
  • Plant Proteins / chemistry
  • Thermodynamics

Substances

  • Albumins
  • Biopolymers
  • Plant Proteins
  • Pectins
  • Ovalbumin