Probing the stability of the food colourant R-phycoerythrin from dried Nori flakes

Ana Simovic; Sophie Combet; Tanja Cirkovic Velickovic; Milan Nikolic; Simeon Minic

doi:10.1016/j.foodchem.2021.131780

Probing the stability of the food colourant R-phycoerythrin from dried Nori flakes

Food Chem. 2022 Apr 16:374:131780. doi: 10.1016/j.foodchem.2021.131780. Epub 2021 Dec 6.

Authors

Ana Simovic¹, Sophie Combet², Tanja Cirkovic Velickovic³, Milan Nikolic⁴, Simeon Minic⁵

Affiliations

¹ Centre of Excellence for Molecular Food Sciences & Department of Biochemistry, University of Belgrade, Faculty of Chemistry, Belgrade, Serbia.
² Université Paris-Saclay, Laboratoire Léon-Brillouin, UMR12 CEA-CNRS, CEA-Saclay, Gif-sur-Yvette CEDEX, France.
³ Centre of Excellence for Molecular Food Sciences & Department of Biochemistry, University of Belgrade, Faculty of Chemistry, Belgrade, Serbia; Ghent University Global Campus, Yeonsu-gu, Incheon, South Korea; Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium; Serbian Academy of Sciences and Arts, Belgrade, Serbia.
⁴ Centre of Excellence for Molecular Food Sciences & Department of Biochemistry, University of Belgrade, Faculty of Chemistry, Belgrade, Serbia. Electronic address: mnikolic@chem.bg.ac.rs.
⁵ Centre of Excellence for Molecular Food Sciences & Department of Biochemistry, University of Belgrade, Faculty of Chemistry, Belgrade, Serbia; Université Paris-Saclay, Laboratoire Léon-Brillouin, UMR12 CEA-CNRS, CEA-Saclay, Gif-sur-Yvette CEDEX, France. Electronic address: sminic@chem.bg.ac.rs.

PMID: 34894468
DOI: 10.1016/j.foodchem.2021.131780

Abstract

This study aimed to characterise the stability of R-phycoerythrin (R-PE), a vivid natural colourant with emerging potential for application in the food industry. High-quality (A₅₆₀/A₂₈₀ ≥ 5), native (α-helix content 75%) R-PE was purified from commercial dried Nori (Porphyra sp.) flakes. Thermal unfolding revealed two transitions (at 56 and 72 °C), ascribed to different protein subunits. Contrary to elevated temperature, high-pressure (HP) treatment showed significant advantages: The R-PE unfolding was partly reversible and the colour bleaching was minimal. Binding of Cu²⁺ (6.3 × 10⁵ M^-1) and Zn²⁺ (1.7 × 10³ M^-1) influenced conformational changes in the protein tetrapyrrole chromophore without affecting R-PE structure and stability (colour). The results give new insights into the stability of R-PE suggesting its usefulness for the replacement of toxic synthetic dyes. Preservation of the red colour of R-PE could be considered in fortified food and beverages by HP processing. R-PE may act as a biosensor for Cu²⁺ in aquatic systems.

Keywords: Binding; High-pressure; Metal ions; R-phycoerythrin; Stability; Temperature.

MeSH terms

Food Coloring Agents*
Phycoerythrin
Porphyra*
Protein Subunits

Substances

Food Coloring Agents
Protein Subunits
Phycoerythrin