Effect of Black Rice Enrichment on the Quality of Fermented Milk Produced with Lactiplantibacillus plantarum

The incorporation of plant-based ingredients into fermented dairy products can enhance their functional value while maintaining product quality. This study investigated the effects of black rice powder enrichment (0-12% w/v) on the key characteristics of fermented milk produced using Lactiplantibacillus plantarum . Increasing the black rice concentration resulted in a significant decrease in pH from 4.98 to 3.81, indicating enhanced acidification. Viscosity and water-holding capacity showed a significant decrease from 2869.33 to 241.33 cP and from 100% to 50%, respectively, reflecting the disruption of the milk protein gel structure. Colour attributes were significantly affected, with lightness (L*) decreasing from 84.09 to 38.15 and a shift toward reddish-purple hues associated with anthocyanin pigments. The probiotic viability remained consistently high across all formulations (8.45-8.81 log CFU/mL), confirming successful fermentation. Sensory evaluation revealed significant differences among treatments, with moderate black rice enrichment (3-6% w/v) achieving the highest overall acceptability, whereas higher substitution levels negatively affected texture and flavour. These findings demonstrate, for the first time, that black rice powder can be effectively incorporated into fermented milk to enhance its functional properties while preserving probiotic viability and consumer acceptance.