Chemical, Microbial, and Sensory Characterization of Juice Prepared Using Carotenoid Pigment Produced by Locally Isolated Rhodotorula mucilaginosa Yeast

This study investigated the extraction of microbial carotenoids from Rhodotorula mucilaginosa and evaluated their potential application as natural colorants in juice formulations. The antibacterial activity of the bio produced β-carotene demonstrated a clear concentration-dependent effect, with inhibition zones reaching 21.67 mm for E. coli, 18.0 mm for Staphylococcus aureus, and 20.0 mm for Salmonella spp. at 50 mg/mL. Sensory evaluation revealed no significant differences among carotenoid-fortified juice, commercial juice, and natural juice across all attributes, indicating high consumer acceptability. Chemical analysis showed a significant increase in total acidity in carotenoid-fortified and natural juices (0.18–0.19), while commercial juice recorded the lowest value (0.13). Mineral content (K, Ca, Na) and pH exhibited no significant variation among treatments, whereas total soluble solids were highest in commercial juice (0.45 g/100 mL). Microbiological assessment confirmed the absence of E. coli, yeasts, and molds in all samples, with low total bacterial counts, reflecting adequate microbial quality. Overall, the findings demonstrate that microbial β-carotene is a promising natural pigment with functional antibacterial activity and suitable technological performance for use in juice production.