Mehmet BAŞLAR, Selen SALLAN, Mustafa Fatih ERTUGAY, Mustafa ŞENGÜL

The effect of acoustic energy on viscosity and serum separation of traditional ayran, a Turkish yogurt drink

Geleneksel Ayranın reolojik davranışları ve depolama sonrası serum ayrılması üzerine akustik enerjinin etkisi araştırıldı. Ayran örnekleri yoğurda %40 (w/w) su ve %1 tuz (w/w) ilave edilerek hazırlandı. Elde edilen Ayranlara 20kHz frekansta çalışan bir ultrases işlemcisiyle 2 ve 4 dakika ultrases işlemi uygulandı. Ultrases genlik seviyesi %40 (22.91W), %60 (33.38W) ve %80 (44.54W) olarak kullanıldı. Viskozite 20, 30, 50, 60, 100, 200 rpm’de rotasyonel viskozimetre kullanılarak ölçüldü. En yüksek viskozite değeri 4 dakikalık işlem süresinde 44.54 güç seviyesinde elde edildi. Ayrıca, akustik enerjinin ayranın serum ayrılması üzerine önemli bir etkiye sahip olduğu gözlendi. Ayranın reolojik özelliklerini tanımlamak için deneysel power-law modeli kullanıldı. Modele ait regresyon katsayıları 0.891 ve 0.997 arasında değiştiği gözlendi. Ayran Newtoniyal olmayan pseudoplastik bir davranış sergiledi.

Geleneksel ayranın viskozite ve serum ayrılması üzerine akustik enerjinin etkisi

The effect of acoustic energy on the rheological behaviour and serum separation during storage of traditional Ayran, which is a mixture of yogurt, water and salt, was investigated. Ayran samples were prepared by the addition of water at a level of 40% (w/w) and salt at a level of 1% (w/w) and stored at 4 °C. They were sonicated for two and four minutes using an ultrasonic generator at a frequency of 20 kHz. The ultrasonic amplitudes used were 40% (22.91W), 60% (33.38W) and 80% (44.54W). Viscosity was measured using a rotational viscometer at the speed of 20, 30, 50, 60, 100 and 200 rpm. The highest apparent viscosity in Ayran was obtained at 44.54 W power level for 4 minutes. In addition, it was obtained that acoustic energy had a significant effect on the serum separation of Ayran. An empirical power-law model was used to describe the rheological behaviour of Ayran samples with regression coefficients between 0.891 and 0.997. Ayran exhibited a pseudoplastic behaviour, non-Newtonian.

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