Yemeklik Yağların Yüzey Gerilimi ve Temas Açılarının Belirlenmesinde Uygulanan Yöntemler

Yüzey gerilimi yüzeyin 1 cm2 artırılması için birim uzunluğa uygulanan kuvvet olarak tanımlanmaktadır. Bir katı yüzeyle temastaki bir sıvının oluşturduğu açıya ise temas açısı denmektedir. Gıda endüstrisinde fırınlanma, kızartma, emülsiye etme gibi proseslerin iyileştirilmesinde ve gıdalarda yeni formülasyonların geliştirilmesinde yüzey özellikleri önemli rol oynamaktadır. Kızartma işlemi, genel olarak gıdaların 150-190°C'deki yağ içerisine daldırılarak lezzet ve kalite özelliklerini geliştirmek amacıyla çok eski zamanlardan beri uygulanan en temel işlemlerden birisidir. Temas açısı ve yüzey gerilimi yağın ıslatma ve penetrasyon özelliklerini etkilemektedir. Bu sebeple yemeklik sıvı yağların yüksek sıcaklıkta temas açılarının ve yüzeyler arası özelliklerinin belirlenmesiyle, bunların kızartma süresince ısı-kütle transferi ve yağ absorbsiyonu üzerine etkileri bulunabilinir. Bu çalışmada yüksek sıcaklıktaki yemeklik yağların temas açılarının ve yüzey geriliminin belirlenmesinde uygulanan yöntemler ve çalışmalar derlenmiştir

Methods for Determination of Surface Tension and Contact Angles of Cooking Oils

Surface tension is the force required to stretch a unit change of a surface area 1 cm2. Contact angle is an angle where a liquid/vaporinterface meets a solidsurface. Surface properties are important in the development of new food products and improvement of processes including frying, baking, and emulsification. Deep-fat frying is one of the most common unit operations in food processing in which immersed food and hot oil come into contact at 150-190°C that improves quality and taste of foods. Contact angle and surface tension affect the penetration and wetting properties of oils. Thus, determination of surface properties of vegetable oils at high temperatures plays a key role for understanding oil absorption and heat-mass transfer during frying. In this review, methods for determination of contact angle and surface tension of cooking oils were summarized

PDF

___

Aydar, A.Y., 2012. Determination of Contact Angle of Olive oil and Canola Oil on a PTFE surface at Elevated Temperatures. Master of Science Thesis, NCSU.
Moreira, R.G., Elena, M.C., Maria, B., 1999. Deep Fat Frying: Fundamentals and Applications. Springer-Verlag LLC: New York, 14, pp 1-350
Blumenthal, M.M., 1991. A new look at the chemistry and physics of deep fat frying. Food Technology 45:68-71.
Mellema, M. 2003. Mechanism and reduction of fat uptake in deep-fat fried food. Trends in Food Science & Technology 14: 364-373.
Dana, D., Saguy, I.S., 2006. Mechanism of oil uptake during deep-fat frying and the surfactant effect-theory and myth. Advances in Colloid and Interface Science 128-130, 267-272.
Zhang, Z., Chen, H., Zhong, J., Saraf, G., Lu, Y., 2007. Fast and reversible wettability transitions on ZnO nanostructures. Journal of Electronic Materials 36: 895-899.
Gajewski, A., 2008. Contact angle and sessile drop diameter hysteresis on metal surfaces. I. J. Heat and Mass Transfer 51: 4628-4636.
Goncalves, F.A.M.M., Trindade, A.R., Costa, C.S.M.F., Bernardo, J.C.S., Johnson , I., Fonseca, I.M.A., Ferreira, A.G.M., 2010. PVT, viscosity, and surface tension of ethanol: New measurements and literature Thermodynamics 42: 1039-1049. J. Chem.
Ho, C.C., Chow, M.C., 2000. The effect of the refining process on the interfacial properties of palm oil. JAOCS 77: 191-199
Da Silva, M.G., Singh, R.P., 1995. Viscosity and surface tension of corn oil at frying temperatures. Journal of Food Processing and Preservation 19: 259-270.
Arnikar, H.J., Kadam, S.S., Gujar, K.N., 1992. Interfacial Phenomena. Essentials of Physical Chemistry and Pharmacy, Orient Longman Limited: Bombay, pp 269-294.
Sedev, R., 2011. Surface tension, interfacial tension and contact angles of ionic liquids. Current Opinion in Colloid and Interface Science, 16: 310-316.
Palit S.R., 1956. Thermodynamic interpretation of the Eötvös constant. Nature 177: 1180
Weast, R.C., 1969. CRC Handbook of Chemistry and Physics 50th Edition. The Chemical Rubber Co.
Mirsasaani S.S., Manjili H.M., Baheiraei N., 2011. Dental Nanocomposites, Advances in Diverse Industrial Applications of Nanocomposites Eds.; Boreddy Reddy: InTech, Chapter 19.
Hidaka, S., Yamashita, A., Takata, Y., 2006. Effect of contact angle on wetting limit temperature. Heat Transfer-Asian Research 35: 513-526.
Adamson, A.W., 1990. Physical Chemistry of Surfaces 5th Edition; Wiley Interscience; New York, pp 777
Handojoa, A., Zhai, Y., Frankel, G., Pascall, M.A., 2003. Measurement of adhesion strengths between various milk products on glass surfaces using contact angle measurement and atomic force microscopy. Journal of Food Engineering 92: 305- 311.
Hicsasmaz, Z., Clayton, J.T., 1993. Applicability and comparison of various techniques for measurement of wettability and contact angles between oil-based liquid and starch-based solid food materials. Journal of Food Engineering 18: 127-143.
Han, K.N., 2002. Fundamentals of Aqueous Metallurgy, SME: Colorado, pp 3-20
Gönül, N., 2000. Çok Fazlı Sistemler I, Yüzey Kimyası ve Colloidler, Ankara.
O'Meara, M., 2012. Determination of the Interfacial Tension between Oil-Steam and Oil-Air at Elevated Temperatures. Master of Science Thesis, NCSU
Millette, J.P., Scott, D.S., Reilly, I.G., Majerski, P., Piskorz, J., Radlein, D., Debruijn, T.J.W., 2002. An apparatus for the measurement of surface tensions at high pressures and temperatures. Can. J. Chem. Eng. 80: 126-134.
Chen, Z., Xia, S., Ma, P., 2008. Measuring surface tension of liquids at high temperature and elevated pressure. Journal of Chemistry Engineering 58: 742-744.
Oreopoulou, V., Krokida, M., Marinos-Kouris, D., 2006. Frying of Foods. In Handbook of Industrial Drying. 3rd Ed. Mujumdar, A. S. Eds.; CRC Press: New York, pp 1225-1245.