Propolis–carboxymethyl cellulose Janus nanoparticles as multifunctional bioactive additives in stirred yogurt

This study developed innovative Janus nanoparticles (JPs) using propolis and carboxymethyl cellulose (CMC) to enhance the technological and functional properties of stirred yogurt. The synthesized propolis-CMC JPs, with an average particle size of 13.40 nm ± 3.56 μm, exhibited remarkable antioxidant activity in both DPPH and FRAP assays, along with potent antibacterial effects against common foodborne pathogens, including Escherichia coli O157:H7 and Listeria monocytogenes, with minimum inhibitory concentrations of 1.5-2.0 mg/mL. Yogurt samples fortified with 0.5, 1, and 5% propolis-CMC JPs were evaluated during 21 days of storage. Incorporation of propolis-CMC JPs, particularly at 5%, significantly reduced syneresis, improved water-holding capacity, and inhibited microbial growth (3.55 ± 0.2 vs. 4.95 ± 0.3 log₁₀ CFU/g in control). Propolis-CMC JPs -enriched yogurts also showed enhanced antioxidant potential and favorable rheological characteristics. Sensory analysis revealed that yogurt with 1% propolis-CMC JPs achieved the highest color and aroma scores, while the 5% formulation exhibited the best texture attributes. These findings confirm that propolis-CMC JPs can act as natural emulsifiers, antioxidants, and antimicrobial agents, effectively addressing key technological limitations of yogurt production.