The effect of pH on the rheological and physical properties of analogue pizza cheese.

This study aimed to evaluate the effect of the pH levels (5.8, 6.0, 6.2, and 6.4) on analogue pizza cheese (APC) rheological and physical characteristics. The APC formulation included 25% vegetable oil and 18.5% rennet casein. The APC samples were made using a Thermomix device and the cheese was stored at + 5 °C for 5 days before it was transferred to - 18 °C. Rotational rheometer measurements showed that all samples followed Herchel-Buckley viscoplastic Model with a different yield stress, highest apparent viscosity, and shear stress values were obtained at pH 6.4 followed by pH 6.2; then the values were dropped by 70%. Melting and stretching showed the best characteristics for the APC sample at pH 6.4, whereas at pH 6.0 stretching values decreased by 77%. The APC samples at pH ≥ 6.2 showed better stability after 6 months of frozen storage in the apparent viscosity than other cheeses. This study concluded that better rheological and physical properties were obtained for the APC at pH ≥ 6.20 and that significant variation for the rheological behavior of the APC can be based on the pH alone, as a slight alteration in the pH was found to affect product quality and acceptability.

Effect of addition of Syrian thyme (Thymus syriacus) on physiochemical and sensory quality of Sudanese Mudaffara cheese during storage.

This study was designed to introduce Syrian thyme (Thymus syriacus) as a new additive flavor for Mudaffara cheese. Mudaffara cheese was prepared from cow's milk using the commonly used black cumin as control and Syrian thyme (0.3 and 0.5%) as treatment. The physiochemical properties and the sensory attributes were evaluated. The results indicated that Mudaffara cheese samples flavored with 0.3% Syrian thyme were significantly (P < 0.05) higher in protein and acidity content compared to the other cheeses. During the storage period, significant (P < 0.05) differences were obtained for all the studied physicochemical parameters except the ash content. Also the interaction of additives and storage period showed significant (P < 0.05) effect on the protein and fat content of Mudaffara cheese samples. However the additives had no significant effect on all sensory characteristics except the general acceptability. According to the panelist test, the overall acceptability of Mudaffara cheese sample flavored with 0.5% Syrian thyme showed the highest numerical score compared to the others Mudaffara cheese samples. During the storage period, Mudaffara cheese samples revealed significant (P < 0.05) variations in texture, acidity, flavor, taste and general acceptability scores. This study concluded that Mudaffara cheese can be flavored with Syrian thyme at a rate of 0.3 and 0.5%. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05634-7.