Pecorino of Appenino Reggiano cheese: evaluation of ripening time using selected physical properties

Physico-chemical properties (texture, colour and image analysis) of Pecorino of Appennino Reggiano cheese were evaluated on six cheese samples at different ripening times (0, 80, 90, 150, 180 and 240 days). Hardness values, obtained by means of texture profile analysis and fracture test, as well as Young's modulus values, significantly increased during ripening. Among other textural parameters, cohesiveness decreased significantly from 0 to 80 days and then remained unchanged for the rest of the ripening time, whereas adhesiveness and springiness did not exhibit a linear trend. L*, b* and C* values decreased significantly with ripening, whereas the percentage area occupied by holes remained unaltered. A statistical model was developed to predict ripening time by means of a step-wise multiple linear regression analysis based on five textural properties (hardness, cohesiveness, chewiness, hardness at fracture and Young' modulus) and three colour parameters (L*, b* and C) (R(2) = 0.984). The model was applied to a validation set of six samples from different milk lots and successfully predicted ripening time with good reproducibility and accuracy (R(2) = 0.971).