Color-Modulated Spirulina Biomass Produced Under Heterotrophic Cultivation as a Sustainable Food Ingredient

The intense green coloration of Spirulina biomass limits its incorporation into food products despite its high nutritional and bioactive value. This study evaluated the heterotrophic fed-batch cultivation of Spirulina sp. LEB 18 using glucose and sodium acetate, aiming to modulate biomass color and preserve a nutritionally relevant composition for its application as a food ingredient. After 10 days, all heterotrophic cultures exhibited attenuation of the green coloration, with total color differences greater than ΔE > 7 relative to the controls. The reduction in chlorophyll a was consistent with the observed color changes, whereas phycocyanin and carotenoid contents did not differ significantly from the autotrophic controls. Cultivation supplemented with sodium acetate fed at 0.2 g L−1 showed a protein composition similar to the control and was the condition that exhibited the greatest color attenuation (ΔE = 10.33) without a pronounced reduction in protein content. Cultures supplemented with glucose resulted in higher lipid and carbohydrate accumulation, reflecting the redirection of carbon toward energy storage compounds. The results demonstrate that heterotrophic cultivation of Spirulina sp. LEB 18 is a promising strategy to modulate biomass color and composition, expanding its applicability, particularly in food matrices where green coloration limits consumer acceptance.