| Popis: |
Yoghurt is one of the most popular fermented dairy products widely consumed all over the world. The present study aimed to evaluate the physicochemical, microbial and sensory characteristics of yoghurt produced by added various levels of Gum Arabic and Guar gum (stabilizers). Physicochemical characteristics, microbial characteristics and sensory evaluation of processed yoghurt samples were conducted under laboratory conditions by standard methods. The results showed that yoghurt produced by the addition of Gum Arabic at concentrations (0.2, 0.35, and 0.5%) had less serum separation (1.6, 1.4, and 3.3 ml/l) after 9 days compared with that produced by adding Guar gum (4.5., 3.1., 0.0 ml/lit), respectively, and their mixture (4.3., 6.1. and 3.5 ml/l). Results reported significant differences in pH values (4.9, 4.5, and 3.9) during storage (0, 3, and 9 days), respectively for all types of stabilizers added. The results illustrated significant differences in total solid (7–8%) at different concentrations during the storage period. The study showed no significant difference in stabilizers (Gum Arabic and Guar Gum). The effect of storage on microbial characteristics was determined and the results showed that all microbial characteristics except coliform bacteria showed a significant decrease in the supplemented yoghurt samples compared with those of control yoghurt, while no effect with stabilizer concentration on microbial characteristics. Sensory characteristics (texture, color, and overall acceptability) were significantly improved, while the flavor was not affected with type and concentrations of stabilizers, but affected with storage period. Yoghurt processed with the addition of Gum Arabic had best quality characteristics than yoghurt made with addition Guar gum and a mixture of them. The study recommended doing more researches in rheological, microbial, and sensory characteristics to improve the quality of yoghurt. |
