Changes in the rheological properties of Iranian UF-Feta cheese during ripening

• Published in: Food chemistry 2009-02, Vol.112 (3), p.539-544
• Main Authors: Karami, M., Ehsani, M.R., Mousavi, S.M., Rezaei, K., Safari, M.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; cheesemaking; elasticity (mechanics); feta cheese; food analysis; food composition; Food industries; Fundamental and applied biological sciences. Psychology; Iranian UF-Feta cheese; Loss modulus; microstructure; Milk and cheese industries. Ice creams; physicochemical properties; protein aggregates; rheological properties; Rheology; Ripening; Storage modulus; texture; ultrafiltration
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2008.06.003

The frequency sweep test was used to evaluate storage modulus (G′), loss modulus (G′′) and loss tangent [tan ( δ)] of Iranian UF-Feta cheese during ripening period (3, 20, 40 and 60 days). With development of ripening, storage and loss moduli increased at varying rates. The rate of increase in G′ was greater than that in G′′ resulting in a reduction in tan ( δ). That is, storage modulus was dominant to loss modulus and as a result the elasticity nature was greater than the viscous nature of cheese samples. Due to the disruption of fat globules and proteolysis, protein matrix rearranged and formed a more compact texture containing aggregates of casein. Ripening did not influence the pH level and also the concentrations of dry matter, fat, salt, and total nitrogen in dry matter. However, water soluble nitrogen increased significantly ( P < 0.05).