Effect of storage time on microstructure, viscoelastic and biochemical parameters of Afuega'l Pitu cheese (PDO): Atroncau Blancu and Roxu varieties

Structural (cryo-scanning electron microscopy), and viscoelastic changes (dynamic rheometry), with storage time in Afuega'l Pitu cheese Blancu (B) and Roxu (R) varieties were observed. Biochemical parameters were also measured. pH, fat, and protein content did not change during the storage time for B and R varieties. R micrographs showed large fused-fat particles within the protein matrix, as a consequence of a specific kneading step to mix the partially dehydrated curd with paprika and salt. B samples exhibited more homogeneous microstructures with small fat globules, improving viscoelastic parameters such as conformational stability (stress amplitude, σmax) and network flexibility (strain amplitude, γmax). The longer storage time, the higher total solids (TS) content (lower moisture to protein ratio-MPR) for B and R varieties, evolving into a less porous microstructure, which increased the thickening of the protein strands. These structural changes were shown in the enhanced rigidity (high complex modulus, G*), structural stability (high σmax) and more shear-sensitive or physically structured (lower γmax) cheese network. •Total solids and kneading were determining factors in the cheese viscoelasticity.•Blancu variety exhibited greater conformational stability and flexibility.•Storage time strengthened the network microstructure of both cheese varieties.