Ali Hala M, Ahmed Jamal A O, El Zubeir Ibtisam E M
Research and Development Center, DAL Food, PO Box 807, 13312 Khartoum North, Sudan.
Department of Dairy Production, Faculty of Animal Production, University of Khartoum, PO Box 321, 13312 Khartoum, Sudan.
J Food Sci Technol. 2023 Feb;60(2):692-700. doi: 10.1007/s13197-022-05654-3. Epub 2022 Dec 2.
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.
本研究旨在评估pH值水平（5.8、6.0、6.2和6.4）对模拟披萨奶酪（APC）流变学和物理特性的影响。APC配方包含25%的植物油和18.5%的凝乳酶酪蛋白。APC样品使用Thermomix设备制作，奶酪在转移至-18°C之前，先在+5°C下储存5天。旋转流变仪测量结果表明，所有样品均符合赫谢尔-巴克利粘塑性模型，屈服应力不同，在pH 6.4时获得最高表观粘度和剪切应力值，其次是pH 6.2；然后这些值下降了70%。融化和拉伸显示，pH 6.4的APC样品具有最佳特性，而在pH 6.0时拉伸值下降了77%。pH≥6.2的APC样品在冷冻储存6个月后，表观粘度方面显示出比其他奶酪更好的稳定性。本研究得出结论，pH≥6.20时，APC具有更好的流变学和物理性能，并且APC流变行为的显著变化仅基于pH值，因为发现pH值的轻微变化会影响产品质量和可接受性。
