The color of food products is an important aspect in food industry, and its preservation
remains a big challenge. We aim to preserve the natural blue dye of C-phycocyanin (C-PC)
phycobiliprotein from Spirulina microalgae. For this purpose, we incorporated C-PC in
combined starch and β-lactoglobulin (BLG) hydrogels by using a high-pressure (HP)
process. Indeed, in thermal treatment, the color derived from C-PC is entirely lost. We
characterized the obtained HP gels by both rheology and small-angle X-ray scattering
(SAXS). Various formulations of binary (BLG/C-PC) and ternary (starch/BLG/C-PC)
systems were tested under HP up to 4,500 bar. A good preservation of the C-PC pigment
was established by mixing BLG and starch with C-PC at pH 7, with concentrations of 180,
5, and 10 mg/mL, respectively. Identical component concentrations were maintained in the
binary systems. Structure of gels was characterized by SAXS providing insight of C-PC
interactions with BLG and starch after HP process which leads to the formation of solid
gels with larger mesh compared to two-component systems. This results in enhanced
mechanical properties, which were determined by amplitude and frequency sweep
measurements using a rheometer with applied plane/plane geometry. Therefore, adding
starch, even at small concentration, significantly improves gel visual appearance and
mechanical properties. Our study reveals that preservation through HP treatment is more
effective than high temperature treatment, as visually observed through the sustained color
integrity of C-PC blue dye
