The Physicochemical, Sensory, and Functional Properties of Yogurt Containing Millet and Milk

With growing consumer demand for functional dairy products, developing yogurts enriched with natural bioactive ingredients has become a research focus. Millet, a traditional cereal rich in polyphenols and dietary fiber, remains understudied in fermented dairy applications. This study evaluated the physicochemical properties, sensory quality, and functional activities of yogurt co-fermented with millet. Millet liquid, pre-treated through gelatinization and α-amylase liquefaction, was co-fermented with milk at addition ratios of 40% and 60% (w/w). The results indicated that millet liquid increased Lactobacillus delbrueckii subsp. Bulgaricus viability (8.55-8.58 log CFU/g vs. 8.26 log CFU/g in the control), improved viscosity (up to 1.0-1.6-fold higher than the control), enhanced texture properties (51-65-fold increase in springiness, 4.3-4.6-fold higher chewiness), and reduced syneresis (18.6-49.2% lower than the control). Sensory evaluation revealed superior flavor and sweetness in millet-enriched yogurt, achieving significantly higher scores than plain yogurt (p < 0.05). Functionally, the 60% millet yogurt showed 77.8% and 84.3% higher DPPH and ABTS radical scavenging capacities, respectively. Additionally, it suppressed DSS-induced inflammatory cytokine secretion in Caco-2 cells (27.2-69.7% inhibition of TNF-α, IL-6, and IL-1β). The improved antioxidant and anti-inflammatory activities may be attributed to polyphenol release from millet. This work highlights the potential of millet-milk co-fermentation for developing yogurts with enhanced texture, sensory appeal, and bioactive properties.