Characteristic evaluation of fermented milk enriched with black rice using Lactobacillus lactis

Food Technology Department, Faculty of Engineering, Bina Nusantara University, Jakarta, Indonesia, 11480

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Abstract

The increasing demand for functional beverages has driven the incorporation of plant ingredients such as black rice (Oryza sativa L.), a promising functional ingredient for enhancing the nutritional quality of fermented milk. This study aimed to develop a fermented milk beverage fortified with black rice powder using Lactobacillus delbrueckii subsp. lactis as the starter culture. Five formulations (F0–F4) were prepared with black rice powder levels ranging from 0% to 12% (w/v) and evaluated for physicochemical, microbiological, and sensory attributes. All formulations supported active fermentation, with viable cell counts exceeding 6 log CFU/mL, thereby complying with the minimum probiotic threshold defined by SNI 7552:2018. Formulations with higher milk content exhibited elevated titratable acidity (up to 4.62%) and lower pH values (4.22–4.61), indicating effective acidification. However, increasing black rice concentration negatively impacted water holding capacity and sensory acceptability, particularly in terms of texture and flavor. Sensory analysis revealed the control sample (0% black rice) achieved the highest overall preference scores, although the formulation containing 3% black rice remained organoleptically acceptable. These findings suggest black rice is a viable functional additive in fermented dairy beverages, provided its concentration must be carefully optimized to maintain product quality and consumer acceptance.