Casein hydration and fat emulsification during manufacture of imitation cheese, and effects of emulsifying salts reduction

• Published in: Journal of food engineering 2011-03, Vol.103 (2), p.179-187
• Main Authors: El-Bakry, M., Duggan, E., O’Riordan, E.D., O’Sullivan, M.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Casein; Casein emulsification; Casein hydration; Cheese; Emulsification; Emulsifying salts; Farinograph; Food engineering; Food industries; Foods; Fundamental and applied biological sciences. Psychology; General aspects; Hydration; Imitation cheese; Liquids; Milk and cheese industries. Ice creams; Reduction; Torque; Torque measurement; Uptakes
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2010.10.014

The manufacture of imitation cheese in a Farinograph was interrupted at various times, and the casein matrix formed and the free liquid were collected and analysed. During manufacture, a torque profile was generated, which showed three distinctive stages; an initial torque peak “peak-1”, followed by a trough and finally a second “peak-2”. Analyses provided quantitative and qualitative evidence that the initial manufacturing stage (peak-1) was concerned with water uptake and the formation of a hydrated casein matrix, as ∼75% of the added water was absorbed. This was followed by a fat emulsification phase (trough) and, once sufficiently emulsified, by the incorporation of the fat to form a homogeneous cheese mass, at peak-2. A similar approach showed that the effect of emulsifying salts reduction was to retard casein hydration, reflected in an increase in peak-1 torque, and led to a prolonged mixing time to sufficiently emulsify fat and allow its incorporation.