Storage Stability of Reduced-Sugar Carrot Milk Beverage: Physicochemical, Functional, and Microbial Assessment

Abstract

Reduced-sugar dairy beverages fortified with plant-based bioactive compounds have gained increasing attention due to their nutritional and functional appeal. This study involve the evaluation of physicochemical stability, functional quality, and microbial safety of reduced sugar carrot beverage during refrigerated storage for 8 days. The developed formulation (4% milk fat and 20% carrot juice) was prepared following a standardized process, and its physicochemical properties (%TS, ash, pH, viscosity, and color attributes), β-carotene content, and antioxidant activity were analyzed using established laboratory methods, while microbiological quality was assessed through Standard Plate Count (SPC), coliform detection, and yeast and mold enumeration. Results showed that total solids decreased slightly (18.27% to 18.07%) and ash content increased marginally (0.732% to 0.750%), while pH remained stable (6.56–6.54), indicating minimal acidification. Viscosity declined from 3.49 to 3.25 cP, consistent with expected structural relaxation and fiber redistribution, and color parameters shifted predictably, with decreasing L*, slightly increasing a*, and stable b* values, reflecting typical carotenoid behavior. β-carotene content declined by approximately 49% (52.76 to 27.07 mg/100 mL) and antioxidant activity decreased from 21.59% to 11.53%, both attributable to oxidative degradation of carotenoid and phenolic compounds during storage. Microbiologically, SPC values remained within acceptable limits (4.73–5.03 log cfu/mL), and coliforms and yeast/mold were consistently absent. Overall, the developed reduced-sugar carrot milk beverage exhibited favorable physicochemical characteristics, acceptable rheological properties, superior nutrient retention, and excellent microbial safety throughout refrigerated storage, validating its suitability as a safe, functional, and shelf-stable dairy beverage for short-term commercial distribution.