Enhancing yogurt health benefits with moringa and black seed oil nanoemulsions to improve fatty acids and microbial viability

The increasing consumer demand for natural functional foods has prompted the development of fortified dairy products with improved nutritional and health benefits. This study designed and evaluated yoghurts fortified with cold-pressed moringa seed oil (MSO) and black seed oil (BSO) at 1.5 g /L, as well as their water-based nanoemulsions at 3 g Nanoemulsion powder/L, compared to a plain control. Phenolic profiles characterized by HPLC-MS revealed high levels of ellagic acid (23.5 mg/100 g), rutin (18.2 mg/100 g), and chlorogenic acid (21.4 mg/100 g) in MSO, and chlorogenic acid (19.8 mg/100 g), apigenin (16.7 mg/100 g), and naringenin (14.3 mg/100 g) in BSO. Nanoemulsions with 5% oil showed droplet sizes of 69.1 nm (MSO) and 38.1 nm (BSO) and zeta potentials above - 30 mV, confirming good colloidal stability over 7 days. Cytotoxicity assays indicated a safe dose up to 80 µg/mL. Yoghurt fortified with nanoemulsions exhibited a significant increase in total solids (+ 12%), unsaturated fatty acids (notably omega-3 increased by 25%), and antioxidant capacity (DPPH radical scavenging improved by 30%) while reducing acidity and syneresis relative to the control. Lactic acid bacteria viability remained unaffected. Sensory evaluation showed improved color, texture, and overall acceptance for yoghurts with 1.5 g nanoemulsion addition per liter. These findings demonstrate that incorporation of MSO and BSO nanoemulsions at this level effectively enhances yoghurt's nutritional and functional properties without compromising microbial or sensory quality.