Zeytinyağı tağşişinin belirlenmesinde kromatografik yöntemlerin kullanılması

Bu araştırma çalışmasında, zeytin pirina yağı karıştırılarak yapılan zeytinyağı tağşişi, yağ asitleri, ECN42 değerleri ve sterol analizleri ile izlenmiştir. Bu amaçla, Kilis yağlık (KY) çeşidinden elde edilen yağlar farklı oranlarda (% 1, 5 ve 10) pirina yağı ile karıştırılmıştır. Yağ asidi ve sterol bileşimlerini analiz etmek için Gaz Kromatografisi (GC) kullanılmıştır. Tağşişi belirlemek için, saf ve katkılı yağların Eşdeğer Karbon Sayısı 42 (ECN42) ve deltaECN42 değerleri de kullanılmıştır. Yağ asidi analizinin sonuçları dikkate alındığında, pirina yağı karıştırılan zeytinyağlarında oleik asit ve palmitik asit oranları azalmıştır. Hileli yağlarda teorik ve deneysel ECN42 değerlerinin farkı (ΔECN42) artmıştır. Sterol bileşimi içinde önemli bir bileşik olan beta-sitosterol oranı, % 10 pirina yağı karıştırıldığında % 81.42'ye kadar yükselmiştir. Yağ örneklerinin Rmar değerleri dikkate alındığında, katkılı yağlar saf yağdan daha yüksek bir değer sergilemiştir. PCA analizlerine göre, yağ numuneleri yağ asitlerine ve TAG profiline göre üç farklı gruba ayrılırken, sterol bileşimine göre dört farklı grupta yer almıştır. Tüm PCA analizlerinde saf KY yağı, tağşişli yağlardan belirgin bir şekilde ayrılmıştır.

Anahtar Kelimeler:

Tağşiş, Zeytinyağı, Yağ asitleri, ECN42 değeri, Steroller

Using chromatographic methods in detection of olive oil adulteration

In research study, olive oil adulteration with olive pomace oil was monitored by fatty acids, ΔECN42 values and sterol analysis. To this end, virgin olive oil obtained from cv. Kilis Yaglik (KY) was mixed with olive pomace oil at different proportion (1, 5 and 10 %). Gas Chromatography (GC) was used to analyse fatty acid and sterol compositions. The fatty acids with Equivalent Carbon Number 42 (ECN42) and ΔECN42 values of pure and adulterated oils were also used to determine adulteration. Considering the results of fatty acids analysis, when olive pomace oil was mixed, the ratios of oleic acid and palmitic acid in olive oil, was decreased. The difference of theoretical and experimental ECN42 values (ΔECN42) were increased in adulterated oils. Beta-sitosterol which is important compound in the sterol composition, increased up to 81.42 % when mixed with 10 % olive pomace oil. Taking into account the Rmar values of the oil samples, adulterated oils displayed higher value than of pure oil. According to PCA analyses, oil samples took placed in three different groups according to fatty acids and TAGs profile, while in four different groups due to sterol composition. In all of the PCA analyzes, pure KY oil was clearly separated from the adulterated oils.

Keywords:

Adulteration, Olive oil, Fatty acids, ECN42 value, Sterols,

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