Soğuk presyon ve kimyasal rafinasyon yöntemleri ile üretilen kanola (kolza) yağlarının bazı fiziksel ve kimyasal özelliklerinin karşılaştırılması
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Dosyalar
Tarih
2009
Yazarlar
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Yayıncı
Namık Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bitkisel yağlara genel kullanım amacıyla rafinasyon işlemi uygulanmakta olup tüketicilerin çoğunluğu rafine yağları tercih etmektedir. Bunun yanında, tüketicilerin minimal işlemler uygulanmış ürünlere ilgisi artış göstermektedir. Son yıllarda, soğuk presyon bitkisel yağların kullanımı önemli oranda hızla artmaktadır. Bu yüzden, soğuk presyon bitkisel yağlarda kalitenin değerlendirilmesi bilhassa önem kazanmaktadır. Bu çalışmanın amacı, soğuk presyon ve kimyasal rafinasyon yöntemleri ile üretilen kanola yağlarının bazı fiziksel ve kimyasal özelliklerini belirlemek ve bu özellikleri karşılaştırmaktır. Bu amaç doğrultusunda, kanola tohumlarından küçük ölçekli bir vida pres yardımıyla soğuk presyon kanola yağı elde edildi. Daha sonra, çöktürme ve filtrasyonla arındırma işlemi gerçekleştirildi. Bu arada, aynı kanola tohumları kullanılarak endüstriyel ekstraksiyon koşullarında ham kanola yağı elde edildi. Ham kanola yağına endüstriyel ölçekte ve klasik koşullarda kimyasal rafinasyon işlemi uygulandı. Bazı fiziksel ve kimyasal özellikleri belirlemek amacıyla, yağ örneklerinde % serbest yağ asitliği, peroksit değeri, Ransimat indüksiyon zamanı (120oC), renk değeri (Lovibond tintometer, 5 ¼" küvet) ve demir, bakır, fosfor elementleri belirlendi. Ayrıca, kapiler gaz-likit kromatografisi ile yağ asiti bileşimleri de incelendi. Araştırmanın bulgularına göre, soğuk presyon kanola yağlarının % serbest yağ asitliği ve peroksit değerleri sırasıyla %0,198-0,217 ve 0,673-0,714 meqO2/kg’dır. Bu kriterler rafine kanola yağlarında ise sırasıyla %0,073-0,085 ve 0,215-0,232 meqO2/kg’dır. Ransimat metodu ile belirlenen indüksiyon zamanları soğuk presyon ve rafine kanola yağlarında sırasıyla 4,50-4,58 saat ve 4,53-4,64 saat olarak belirlenmiştir. Renk değerleri ile bakır, demir ve fosfor içerikleri soğuk presyon kanola yağlarında daha yüksek düzeydedir. Ayrıca, rafine kanola yağları %0,30-0,42 düzeyinde trans yağ asiti içermektedir. Trans yağ asiti toplamını C18:1, C18:2 ve C18:3 yağ asitlerinin izomerleri oluşturmaktadır. Buna karşın, soğuk presyon kanola yağlarında trans yağ asiti belirlenememiştir. Soğuk presyon kanola yağlarının Ransimat metodu ile belirlenen oksidatif stabilite değerlerinin rafine kanola yağlarına çok benzer olduğu, buna karşın % serbest yağ asitliği ve peroksit değerlerinin ise daha yüksek olduğu elde edilen sonuçlardan anlaşılmaktadır. Diğer taraftan, rafinasyon koşullarının yağ asiti bileşimlerinde minör değişimlere neden olduğu rafine kanola yağları, belirlenebilir düzeyde trans yağ asiti içermektedir. Bitkisel sıvı yağlarda trans yağ asiti varlığı uygulanan proses koşulları hakkında fikir veren önemli bir parametredir. Soğuk presyon işlemiyle stabil ve yüksek kaliteli kanola yağı elde edilebilmesi için optimum proses koşullarının uygulanması ve iyi kalitede kanola tohumlarının kullanılması önemli gerekliliktir.
Vegetable oils intended for usual consumption are refined. Most consumers use refined oils. On the other hand, the consumers’ interest for minimally processes products has increased. The use of coldpressed vegetable oils has increased significantly during the last years. Thus, it is especially important to evaluate the quality of cold-pressed vegetable oils. The aim of this study was to determine the some physical and chemical properties of cold-pressed and chemical refined canola oil, and to compare these properties. For the reason, the cold-pressed canola oil was in small-sized facilities produced by extraction of canola seeds using only a screw press and purifying the oil by sedimentation and filtration. Meanwhile, crude canola oil was obtained from some canola by industrial extraction process. The crude oil was industrially subjected to conventionally chemical refining. For the determination of some physical and chemical properties of cold-press and refined canola oils, free fatty acids, peroxide value, Rancimat induction time (at 120oC), color value (Lovibond tintometer, 5 ¼ inch cell) and iron, copper, phosphorus elements of the oil samples were measured. Also, the fatty acid compositions of the oils samples were determined by capillary gasliquid chromatography. According to the findings of the research, free fatty acids and peroxide values for the cold-pressed canola oils were in the ranges 0.198-0.217 % and 0.673-0.714 meqO2/kg, respectively. These parameters in the refined canola oils were in the ranges 0.073-0.085 % and 0.215-0.232 meqO2/kg, respectively. Induction time for oxidative stability by the Rancimat method in the cold-press and the refined canola oils was in the ranges 4.50-4.58 h and 4.53-4.64 h, respectively. Color values and contents of copper, iron, phosphorus in the cold-press oils were higher than that of the refined canola oils. In addition, the total trans fatty acid contents of refined canola oils were 0.30-0.42 % of total fatty acids. The total trans fatty acids comprised isomers of the C18:1, C18:2 and C18:3 fatty acids. However, cold-press canola oils contained no measurable amounts of trans fatty acids. The results obtained showed that the oxidative stability of the cold-press canola oils was very similar in comparison to the refined canola oils under the conditions of the Rancimat method. However, free fatty acids and peroxide values were higher in the cold-press canola oils compared to the refined canola oils. On the other hand, the fatty acid compositions of canola oils showed minor changes under conventionally industry refining conditions. Also, refined canola oils contained measurable amounts of trans fatty acids. The important parameter for the detection of an improper processing for vegetable oils is the determination of the trans fatty acids. To obtain stable high quality canola oil by cold pressing, it is important that optimal processing conditions be applied and be make used of good quality seeds.
Vegetable oils intended for usual consumption are refined. Most consumers use refined oils. On the other hand, the consumers’ interest for minimally processes products has increased. The use of coldpressed vegetable oils has increased significantly during the last years. Thus, it is especially important to evaluate the quality of cold-pressed vegetable oils. The aim of this study was to determine the some physical and chemical properties of cold-pressed and chemical refined canola oil, and to compare these properties. For the reason, the cold-pressed canola oil was in small-sized facilities produced by extraction of canola seeds using only a screw press and purifying the oil by sedimentation and filtration. Meanwhile, crude canola oil was obtained from some canola by industrial extraction process. The crude oil was industrially subjected to conventionally chemical refining. For the determination of some physical and chemical properties of cold-press and refined canola oils, free fatty acids, peroxide value, Rancimat induction time (at 120oC), color value (Lovibond tintometer, 5 ¼ inch cell) and iron, copper, phosphorus elements of the oil samples were measured. Also, the fatty acid compositions of the oils samples were determined by capillary gasliquid chromatography. According to the findings of the research, free fatty acids and peroxide values for the cold-pressed canola oils were in the ranges 0.198-0.217 % and 0.673-0.714 meqO2/kg, respectively. These parameters in the refined canola oils were in the ranges 0.073-0.085 % and 0.215-0.232 meqO2/kg, respectively. Induction time for oxidative stability by the Rancimat method in the cold-press and the refined canola oils was in the ranges 4.50-4.58 h and 4.53-4.64 h, respectively. Color values and contents of copper, iron, phosphorus in the cold-press oils were higher than that of the refined canola oils. In addition, the total trans fatty acid contents of refined canola oils were 0.30-0.42 % of total fatty acids. The total trans fatty acids comprised isomers of the C18:1, C18:2 and C18:3 fatty acids. However, cold-press canola oils contained no measurable amounts of trans fatty acids. The results obtained showed that the oxidative stability of the cold-press canola oils was very similar in comparison to the refined canola oils under the conditions of the Rancimat method. However, free fatty acids and peroxide values were higher in the cold-press canola oils compared to the refined canola oils. On the other hand, the fatty acid compositions of canola oils showed minor changes under conventionally industry refining conditions. Also, refined canola oils contained measurable amounts of trans fatty acids. The important parameter for the detection of an improper processing for vegetable oils is the determination of the trans fatty acids. To obtain stable high quality canola oil by cold pressing, it is important that optimal processing conditions be applied and be make used of good quality seeds.
Açıklama
Anahtar Kelimeler
soğuk presyon, yağ asiti bileşimi, oksidatif stabilite, kanola, rafinasyon, cold-pressing, fatty acid composition, oxidative stability, canola, refining
