Evaluation of Changes of the Chemical , Rheological and Organoleptic Characteristics of Ras Cheese during Ripening

Abstract

Changes in the Principal Component Analysis (PCA) of local Ras cheese were examined. Chemical, rheological and organoleptic properties of the cheese were examined during the ripening period of 30, 60 and 90 days. The relationship between chemical and rheological data was estimated by the Canonicial Correlation Analysis. Ras cheese were collected from six different local cheese factories in fayoum governorate, at the age of 15 days. All experimental cheeses were transported and stored at 12±2°C and 88 % relative humidity for 90 days. The PCA describe three groups of cheese samples including 30, 60, and 90 days aged cheeses by testing the chemical and rheological changes during the ripening period. The PC 1 (30 days cheeses) characterized with higher moisture content, pH and cohesiveness values than PC3 samples (90 days cheese) which were of the highest water soluble nitrogen /total nitrogen, firmness, chewiness and gumminess values. The PC 2 distinguished the cheese being characterized by the highest fat and protein contents at 60 days. Strong correlations were established between the chemical and rheological CCA results. Continuous and gradual improvement in the sensory quality of all cheeses were observed during ripening period, attaining the highest score at the end of ripening period (90 days).