• Phycocyanin stability is enhanced by forming complexes with zein and resveratrol. • PZR-3:1 shows stability with ∆E reduced by 28.4% after heating at 90°C for 15 min. • PZR-3:1 shows stability with ∆E reduced by 81.3% after 14 days of light exposure. • Hydrogen bonds and hydrophobic interactions drive the formation of the complex. • The complex offers a natural solution for stabilizing PC in food applications Phycocyanin is a natural pigment with significant antioxidant properties, but its instability under heat and light limits its applications in the food industry. This study aims to enhance the thermal and light stability of phycocyanin by forming complexes with zein and resveratrol (PC-Zein-RES). PC-Zein-RES complexes (PZR-5:1, PZR-3:1, and PZR-1:1) were prepared using an antisolvent precipitation method with a fixed PC-to-Zein mass ratio of 1:1 and varying resveratrol concentrations (5:1, 3:1, and 1:1 w/w). The complexes were characterized by particle size and zeta potential analysis, fluorescence spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. Our results show that the incorporation of resveratrol significantly reduced the average particle size to 86.94−93.75 nm by 23.7%-29.2% decrease and improved structural compactness. PZR-3:1 exhibited improved stability, with ∆E reduced by 28.4% after heating at 90 °C for 15 min and by 81.3% after 14 days of light exposure. Instrumental analysis showed that strong hydrogen bonding and hydrophobic interactions occurred among phycocyanin, zein, and resveratrol, leading to the formation of a protective matrix that preserved the chromophore structure. The PC-Zein-RES complex provides a more robust protective system for phycocyanin, making it suitable for applications in plant-based beverages and dairy alternatives, where pigment stability is essential. This study presents a novel approach to stabilizing natural pigments, which can enhance the shelf-life and sensory quality of clean-label food products.
Liu et al. (Sun,) studied this question.