Volatile profile, textural and sensory properties of Diyarbakır Örgü cheese produced from sheep and cow milk of different ripening time

Diyarbakır Örgü (knitted) cheese (DOC) is a semi-fat, hard, and a pasta-filata type cheese. The objective of this study was to evaluate volatile organic compounds (VOC), and textural and sensory properties of DOC during the 120-day maturation period. For this purpose, a total of 5 different cheeses were produced as 100% sheep’s milk (C1), 100% cow’s milk (C2), 90% sheep’s milk + 10% cow’s milk (C3), 80% sheep’s milk + 20% cow’s milk (C4), and 70% sheep’s milk + 30% cow’s milk (C5). During the ripening, a total of 31 compounds, including esters (9), alcohols (5), acids (5), ketones (5), aldehydes (4), and miscellaneous (3), were identified in all cheese samples. Volatile compounds increased, both qualitatively and quantitatively, along with the increase of the percentage of sheep milk used in the cheese production increased. At the beginning of ripening, the total amount of VOC in the DOC obtained from sheep’s milk was 3.27-fold greater than that of the produced cow’s milk, while this ratio increased to 4.57 at the end of ripening. The total VOC contents of all the DOC reduced along the ripening and decreased by 53.37, 64.92, 15.53, 51.81, and 64.84% for C1, C2, C3, C4, and C5, respectively. As the amount of cow's milk used in DOC production increased, the values of all textural properties (hardness, adhesiveness, springiness, cohesiveness, gumminess, and chewiness) of the cheese increased too. On the other hand, these values decreased with the maturation (p<0.05). The rates of decrease in hardness (N), adhesiveness (N.s), springiness (cm), cohesiveness, gumminess (N), and chewiness (mJ) values of the cheese groups with the storage were C1>C3>C2>C4>C5, C4>C1>C5>C2>C3, C2>C1>C3>C4>C5, C3>C2>C1>C5>C4, C1>C4>C3>C2>C5 and C3>C4>C1>C5>C2, respectively. In terms of sensory properties (colour, texture and, taste-aroma) of the cheese mature C2, mature C1 and 30-day ripened C1 cheese samples were preferred more, respectively.