$beta$ -lactoglobulin variants in Awassi and Morkaraman sheep and their association with the composition and rennet clotting time of the milk

Bu çalışmada, poliakrilamidjel elektroforezi kullanılarak, İvesi ve Morkaraman koyun ırkında $beta$ -Lg genetik varyantları tespit edilmiş ve bu varyantların sütün bileşimi ve pıhtı oluşum süresi ile ilişkisi saptanmıştır. Her iki koyun ırkında 2 farklı $beta$ -Lg allel geni (A ve B) ve 3 farklı $beta$ -Lg genotipi (AA, AB ve BB) gözlenmiştir. $beta$ -Lg A ve B gen frekansları, İvesi ırkında 0,63 ve 0,37, Morkaraman ırkında ise 0,56 ve 0,44 olarak hesaplanmıştır. Bu sonuç, her iki koyun ırkında da $beta$ -Lg A geni frekansının daha yüksek olduğu göstermektedir. Her iki koyun ırkı sütlerinde de, p-Lg varyantları ile sütün bazı özellikleri arasında istatistiksel olarak önemli ilişkiler elde edilmiştir (P < 0,01). İvesi ırkı sütlerinde $beta$ -Lg BB varyantı, yüksek yağ ve düşük laktoz oranı ile, Morkaraman sütlerinde ise p-Lg BB varyantı yüksek protein ve yağsız kurumadde oranı ile ilişkili olduğu tespit edilmiştir. Diğer taraftan, İvesi sütlerinde p-Lg AA varyantlı sütlerde pıhtılaşma süresinin kısa olduğu; Morkaraman ırkı sütlerinde ise P-Lg BB varyantlı sütlerde pıhtılaşma süresinin daha kısa olduğu gözlenmiş, ancak sonuç istatistiksel olarak önemli bulunmamıştır. Sonuç olarak $beta$-Lg BB varyantlı sütler, peynir teknolojisi açısından önem taşımaktadır.

İvesi ve Morkaraman koyun ırklarında $beta$ -lactoglobulin varyantları ve sütün bileşimi ve pıhtı oluşum süresi ile ilişkisi

In this study, $beta$ -lactoglobulin ( $beta$ -Lg) variants in Awassi and Morkaraman sheep were studied using polyacrylamide gel electrophoresis, and their association with composition and rennet clotting time of the milk was estimated. Two alleles (A and B) and 3 different genotypes for $beta$ -Lg (AA, AB and BB) were observed in the whey from both breeds. The frequencies of $beta$ -Lg alleles were estimated as A 0.63 and B 0.37 in the Awassi breed, and A 0.56 and B 0.44 in the Morkaraman breed. These results indicate high $beta$ -Lg A frequencies in both sheep breeds. Significant relationships were obtained between $beta$ -Lg variants and some properties of the milk from both sheep breeds (P < 0.01). In the Awassi breed, milks with $beta$ -Lg BB had significantly higher fat content and lower lactose content, while milks with the same variant had higher protein and solid non-fat contents in the Morkaraman breed. On the other hand, milks with the $beta$ -Lg AA variant in the Awassi breed had a short rennet clotting time, while milks with this variant in the Morkaraman breed had the lowest value for rennet clotting time but the result was not statistically significant. Therefore, it could be concluded that milks with the BB genotype are of importance in terms of cheese technology.

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