Publication

Abstract : Natural food colorants with bioactive properties are gaining attention as safer alternatives to synthetic dyes. In this study, monascorubrin and rubropunctatin pigments were produced by submerged fermentation of Monascus purpureus F1 and Talaromyces purpureogenus F2, yielding purified pigments with maximum absorbance at 450 nm. Both pigments displayed strong pH stability at pH 7 and retained >90 % absorbance after 10 h at 100 °C, with monascorubrin showing slightly greater tolerance to alkaline conditions. Pigment extracts were spray-dried using varying inlet temperatures (165–180 °C) and maltodextrin concentrations (5–9 % w/v). The highest recovery was achieved at 175 °C with 5 % maltodextrin, producing yields of 98 ± 1.7 % for monascorubrin and 99 ± 2.1 % for rubropunctatin and solubility indices of 83 % for both. Total phenolic content reached 220.2 ± 0.8 mg GAE/g for monascorubrin and 210.3 ± 0.13 mg GAE/g at 5 % maltodextrin, with antioxidant activity of 75.9 % and 74.8 % DPPH scavenging, respectively. Cytotoxicity assays on Vero cells confirmed >95 % viability at food-relevant concentrations (10–30 mg/mL), indicating absence of mycotoxin-related toxicity. When incorporated into yoghurt and ice cream (30 mg/mL), the pigments maintained stable pH, titratable acidity, and total solids during 15–60 days of refrigerated storage, with rubropunctatin imparting a more vivid red hue (a* =43–50) than monascorubrin (a* =16–20).