Title : Food-grade C-phycocyanin produced at pilot scale: A natural blue food colorant with potential functional food applications
Abstract:
C-phycocyanin (C-PC), a natural blue phycobiliprotein produced by Arthrospira maxima (spirulina), has attracted increasing attention as a natural blue food colorant and a potential functional food ingredient because of its antioxidant properties and natural origin. As consumer demand for clean-label foods and bioactive food ingredients continues to grow, the development of sustainable and economically viable production systems for food-grade C-PC has become increasingly important. However, large-scale production of C-PC in mid-latitude regions remains challenging because seasonal fluctuations in natural light reduce biomass productivity and pigment accumulation. In this study, a previously optimized red:blue (8:2) LED lighting strategy was applied to pilot-scale (5,000 L) greenhouse raceway ponds to establish a stable production platform for food-grade C-PC. Biomass concentration and C-PC productivity were evaluated over four cultivation seasons under natural sunlight, continuous LED supplementation, and nighttime LED supplementation. The produced C-PC was characterized using High-Performance Liquid Chromatography (HPLC) and Fourier-transform infrared spectroscopy (FTIR). Pigment purity was determined spectrophotometrically, antioxidant activity was evaluated using DPPH and ABTS radical scavenging assays, and the economic feasibility of supplemental LED operation was also assessed. Nighttime LED supplementation increased C-PC production by 1.7- to 2.5-fold compared with natural sunlight cultivation while maintaining pigment productivity comparable to continuous LED illumination. HPLC chromatograms confirmed the characteristic α- and β-subunits of C-PC, and FTIR spectra demonstrated structural characteristics comparable to those of a commercial C-PC standard. The produced C-PC exhibited a purity index of 0.75, satisfying the food-grade criterion (purity index≥0.7). Furthermore, C-PC demonstrated strong DPPH and ABTS radical scavenging activities, indicating that its antioxidant activity was retained following pilot-scale production. Economic analysis further demonstrated that nighttime LED supplementation reduced energy consumption while maintaining high pigment productivity, providing greater cost-effectiveness than continuous LED illumination. These findings demonstrate that nighttime LED supplementation provides a sustainable and economically viable strategy for the pilot-scale production of food-grade C-PC under mid-latitude conditions. The proposed production platform supports the commercialization of microalgae-derived C-PC as a natural blue food colorant and highlights its potential as a functional food ingredient for future clean-label and health-promoting food applications.
