Katia Amer Elias^1*, Abdul Wahab Sino Marai² and Sharif Hassan Sadiq²

1 Food Engineering Department, Faculty of Chemical and Petroleum Engineering, University of Homs, Syria.
2 Food Science Department, Faculty of Agriculture, University of Damascus, Syria.
(*Corresponding author: Katia Amer Elias, Email: Katia.elias9118@gmail.com, Mob: 0987044624).

Received: 11/ 3/ 2026     Accepted: 21 / 6/ 2026

Abstract: 

A series of experiments were conducted at Homs University, within the laboratories of the Food Engineering Department, Faculty of Chemical and Petroleum Engineering, on the fortification of yogurt. Yogurt made from cow’s milk served as a control, while samples of milk were added to spirulina at 37°C at a concentration of 0.3%, 0.5%, and 0.7%. Fermentation continued for 24 hours, during which the counts of both bacilli and lactic acid bacteria were recorded. After fermentation at a pH of 4.6, all samples were evaluated sensory, chemical, and physically. The results showed that fortifying yogurt with spirulina activated lactic acid bacteria and increased protein and antioxidant levels in the studied samples with increasing spirulina concentration, without significantly affecting fat content. Carbohydrates, thus increasing the nutritional value of the milk and improving its physical and chemical properties, showed that milk samples fortified with 0.5% spirulina exhibited higher sensory acceptance compared to other treatments. Both bacilli and spheroids recorded the highest growth rates, reaching 8.6 logcfu/ml and 8.4 logcfu/ml, respectively. The amount of lactic acid formed after 24 hours increased from 0.9% to 1.1%, while the protein content rose to 3.30% → 3.65%, and antioxidants increased from 22 ± 1.5% → 46 ± 2.3%, respectively.

Keywords: Lactic acid fermentation, spirulina, nutritional value, fortified fermented milk.

 Full paper in Arabic: PDF