Characteristic Evaluation of Fermented Milk Enriched with Black Rice Using Lactocobacillus lactis

Abstract

This study explores the development of a fermented milk beverage enriched with black rice extract using Lactococcus lactis as the starter culture. Five formulations were prepared by varying the ratio of black rice powder and full cream milk powder (F0 to F4, from 0% to 12% black rice). The samples were evaluated for their physicochemical, microbiological, and sensory properties. Results showed that L. lactis was able to effectively ferment all formulations, with viable cell counts exceeding the minimum requirement of 6 log CFU/mL as specified by SNI 7552:2018. The highest titratable acidity (4.62%) and favorable pH values (ranging from 4.61 to 4.22) were observed in milk-dominant formulations. However, increasing the proportion of black rice extract resulted in reduced water holding capacity and overall acceptability due to diminished texture and flavor. Sensory analysis revealed that the control formulation (F0, 12% milk without black rice) received the highest scores for color, aroma, taste, texture, and overall preference. These findings indicate that while L. lactis can successfully ferment black rice–milk mixtures, formulation optimization and incorporation of food additives are necessary to enhance product quality, particularly in formulations with higher black rice content.