Relation between pH, degree of proteolysis and consistency in soft cheeses

Hard and acid body is a common texture defect in soft cheeses like Italian Crescenza and Cremoso, a popular Argentine soft cheese. It results from poo r texture development during maturation, such that the cheese body remains acid, hard and crumbly. A study of the causes of this phenomena is reported in the present work. Cheesemaking was performed using either a direct star ter of Streptococcus salivarius ssp. thermophilus strains (control) or a na tural milk culture (experimental). The curd was allowed to reach pH 5.2 for control cheeses and 4.7 for experimental ones before salting. Proteolysis characterisation was performed by nitrogen fraction analysis, Urea-PAGE, RP -HPLC and free amino acid analysis. Texture and appearance were very differ ent. Control cheeses were soft and creamy, while experimental cheeses exhib ited defective texture. Proteolysis in both of them was nevertheless simila r. It is concluded that texture defect can be related, in this case, to the large influence of pH of the curd before brining on casein micelles' netwo rk organisation and not to a minor degree of proteolysis.