Effect of aqueous extract of doum (Hyphaene thebaica L.) fruit on the physicochemical, microbiological, antioxidant, antimicrobial, and sensory properties of set-type yogurt

Doum fruit, which contains valuable nutritional components and biologically active substances while being readily available, low-cost, and offering numerous health benefits, may present an innovative approach to yogurt fortification. The present study evaluated the physicochemical properties, microbiological counts, total phenolic content, total flavonoid content, antioxidant activity, antimicrobial activity, and sensory properties of set-type yogurt fortified with aqueous extract of doum fruit. The set-type yogurt samples were prepared with 5% and 10% aqueous extract of doum fruit and stored under refrigeration (4°C ± 1°C) for 21 d. The incorporation of aqueous extract of doum fruit improved the chemical composition of yogurt by increasing TS, protein, fat, ash, and dietary fiber contents compared with the control. The highest fiber content was recorded in the set-type yogurt fortified with 10% extract (0.92 ± 0.02 g/100 g) on d 21. Titratable acidity was lower in both fortified set-type yogurt samples compared with the control, with the 10% extract sample exhibiting the lowest value (0.88% ± 0.02%) on d 21. Antioxidant activity increased significantly in both fortified set-type yogurt samples, with the 10% extract sample showing the highest inhibition rate (49.80% ± 2.00%) on d 21. All set-type yogurt samples demonstrated antimicrobial activity, with the 10% extract sample producing the largest inhibition zones. Sensory evaluation showed that the yogurt fortified with 10% extract received the highest overall acceptance scores, particularly for taste, smell, and texture. These findings suggest that set-type yogurt enriched with aqueous extract of doum fruit represents a promising functional dairy product with enhanced antioxidant and antimicrobial activities while maintaining desirable sensory attributes. Further research is warranted to investigate the bioavailability and in vivo efficacy of its bioactive compounds.