Effect of immunoglobulin G supplementation on stability, fatty acid profile, organic acids, lipid oxidation and sensory features of cheddar cheese

Immunoglobulin G (IgG) possesses numerous health benefits, it is a part of whey proteins which are mostly lost in whey and cheese curd virtually contains no IgG. In this study, bovine IgG was supplemented to the cheddar cheese curd at salting phase at four levels, i.e. 5, 10, 15, 20, and 0 mg/kg and labeled as T₁, T₂, T₃, T₄, and control, respectively. After vacuum packaging, all types of samples were stored at 5-6 ºC for three months for ripening. IgG supplementation at all four concentrations did not affect cheddar cheese composition. After the completion of ripening phase, total viable count of control, T₁, T₂, T₃ and T₄ were 7.91, 7.84, 7.75 and 6.18 log CFU/mL (p < 0.05), respectively. Three months old cheddar cheese samples showed that retention/ stability of IgG in all treatments. In T₄, magnitudes of citric acid, lactic acid, acetic acid and propionic acid were 2577, 17,974, 192, and 288 ppm, respectively. Supplementation of cheddar cheese with IgG from 5-20 mg/kg did not change the fatty acid composition at the stages of cheddaring, pressing and ripening; however, ripening of cheddar cheese for three months considerably altered the fatty acid composition. After the completion of ripening phase, peroxide value of control, T₁, T₂, T₃, and T₄ was 0.29, 0.30, 0.28, 0.32, and 0.31 (meq O₂/kg), respectively, with no variation in cholesterol contents of all variants of IgG supplemented cheese. Flavor scores of three months old control and all the treatments were more than 90% of the total scores (9).