High-pressure processing (HPP) of phycocyanin extract solutions: Enhancing stability through molecular interactions

• Published in: Food science & technology Vol. 198; p. 115965
• Main Authors: Faieta, Marco, Chen, Chang, Colaruotolo, Louis A., Huynh, Leslie, Corradini, Maria G., Pittia, Paola
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.04.2024
• Subjects: amino acids; anisotropy; Arthrospira platensis (spirulina); cold pasteurization; color; fluorescent dyes; Food colorant; High hydrostatic pressure; Microalgae; oxygen; particle size; phycocyanin; polypeptides; Protein structure; temperature; Food colorant; Arthrospira platensis (spirulina); High hydrostatic pressure; Microalgae; Protein structure
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2024.115965

C-Phycocyanin (PC) has been proposed as a replacement for synthetic colors in foods. However, C-PC stability is adversely affected during food processing due to exposure to high temperature, pressure, oxygen concentration or extreme pHs. This study assessed the degradation mechanisms of C-PC under a nonthermal pasteurization technology, i.e., High-Pressure Processing (HPP), and identified potential processing protocols to arrest C-PC instability at low pH. Aqueous C-PC solutions (pH:4–6) were subject to HPP (500–600 MPa) for 1–5 min. C-PC stability was monitored based on changes in the photophysical properties of its fluorophores (phycocyanobilin chromophore and aromatic amino acid residues) and particle size. pH significantly affected C-PC's stability towards HPP (<stability at < pH). Sharper hypsochromic (blue) shifts, lower intensity, and higher anisotropy were observed as pressure and treatment time increased, which suggested conformational changes in C-PC's polypeptides, followed by aggregation. pH adjustment after HPP treatments resulted in a significant reduction in color loss and aggregation, possibly due to partial stabilization of the polypeptide subunits' conformation. [Display omitted] •pH significantly increases C-PC instability to HPP (<stability, <pH).•Blue shifts and high anisotropy evidenced HPP-induced conformational changes in C-PC.•Peptide subunits' conformational favored aggregation and chromophore instability.•pH adjustment after HPP significantly diminished C-PC degradation during HPP.