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  In this study, the effect of using palm and corn oils as a partial or whole Substitution of milk fat (0, 33, 50, 66, and 100%) on the physical and chemical properties of pizza processed cheese was investigated. No significant effect was found on the meltability and strechability of pizza cheese made by different oil sources, whereas, oiling off, iodine number as well as saponification number were significantly affected by the type of oil used in the formulation of pizza cheese (p<0.05). The high correlation (-0.717) between the oiling off and saponification number enable us to use the later as a diagnostic element to distinguish pizza cheeses made by vegetable oil sources as a replacement of milk fat which is illegal in some countries as well as Iran.

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Increasing soy protein isolate content may be a practical and cost-effective means to control the functional properties of imitation pizza cheese. Imitation cheeses containing 2, 3 and 5% (w/w) soy protein isolate as a partial caseinate substitute were manufactured and dynamic rheology of these products were compared to a control (0% w/w soy protein isolate) in temperature sweep analysis. The dynamic rheological properties of caseinate-based imitation cheeses containing various concentrations of soy protein isolate were investigated using a strain-controlled rheometer. The storage modulus (G’), the loss modulus (G”) and the loss angle (Tan‌) were measured as a function of temperature (35–100°C). The storage modulus and loss modulus of imitation cheeses was significantly decreased (P0.05) at all examined temperatures (35–100‌) with the inclusion of soy protein isolate. Inclusion of soy protein isolate significantly increased imitation cheese peak Tan‌ values compared to control (P0.05), and the inclusion of 5% (w/w) soy protein isolate as a partial caseinate substitute had the greatest effect. In sensory evaluation, in terms of texture and mouthfeel, flavour and total acceptance the highest score belonged to control, while in all of samples lowest score observed in sample containing 5% w/w soy protein isolate. The results of this study showed that varying the level of soy protein isolate altered dynamic rheological properties as a function of temperature and thus the functionality (for example, meltability), as well as sensory attributes of imitation pizza cheeses.

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Along with the increase in pizza cheese production and consumption, identifying the trends of altering the functional properties of this product in order to control its quality is becoming very important. In this study, the changes in Functional properties of processed pizza cheese and low moisture mozzarella cheese samples collected from local manufactures in Khorasan province, Iran were analyzed. Three samples of commercial processed pizza cheeses and one commercial low moisture Mozzarella cheese as well as a sample of processed pizza cheese prepared according to the formulation previously optimized in our laboratory, were collected and stored at 4 ° C in vacuum packages until the day of experiment. Functional properties of all samples such as stretch length, max load, oiling off and meltability were measured and analyzed in days 0, 14 and 28 after production. In general, Statistical analysis showed that storage time had a significant (p≤ 0.05) effect on all measured properties, so that the stretch properties of  low moisture mozzarella cheese and all samples of processed pizza cheese were decreased significantly (p≤ 0.05) during the storage period, whereas meltability and oiling off, follow a significant increase in trend. None of the properties evaluated were out of their standard and acceptance levels at the end of the shelf life, Therefore, it is concluded that the storage of pizza cheese in the fridge instead of freezer up to one month after production is suggested to be an alternative to protect the product from the damage caused by freezing and defrosting while maintaining the quality of the product at the end of the shelf life. The efficacy of TPA and image processing techniques in the measurement of functional properties (stretchability, oiling off and meltability) of pizza cheese samples was also confirmed in this study.