Milföy hamurunun ısıl yayınım katsayısının sıcaklıkla değişiminin belirlenmesi

Bu çalışmada milföy hamurunun ısıl yayınım katsayısı modifiye edilmiş Dickerson metodu kullanılarak -35 °C ile +10 °C sıcaklık aralığında deneysel olarak ölçülmüştür. Örneğin donmuş durumdaki ısıl yayınım katsayısının donmamış durumuna ait ısıl yayınım katsayısından daha yüksek olduğu ve sıcaklığın artmasıyla azaldığı tespit edilmiştir. Donmuş durum için elde edilen ölçüm sonuçlarına regresyon analizi uygulanarak milföy hamurunun ısıl yayınım katsayısının sıcaklıkla değişimini veren empirik denklem elde edilmiştir. Donmamış durumda, 3-10 °C sıcaklık aralığında örneğin ısıl yayınım katsayısı 1.08 x $10^{-7}$ m²/s olarak ölçülmüştür.

Changes of thermal diffusivity of puff pastry dough with temperature

Thermal diffusivity of puff pastry dough was measured in the temperature range from –35 to +10 °C, by using modified Dickerson method. Thermal diffusivity of the frozen dough found to be greater than unfrozen sample and was found to be decreased with temperature for the frozen state. Empirical equation for thermal diffusivity calculations were obtained by application of regression analysis to the results for the frozen state. Thermal diffusivity of puff pastry dough was measured as 1.08 x $10^{-7}$ m²/s between 3 and 10 °C.

PDF

___

Singh RP. 1995. Thermal properties of frozen foods. In Engineering Properties of Foods, MR Rao and SSH Rizvi (eds), pp.139-166, Marcel Decker Inc., New York.
Delgado AE, Gallo A, De Piante D and,Rubiolo, A. 1997. Thermal conductivity of unfrozen and frozen strawberry and spinach. J. Food Eng., 31:137-146.
Sweat VE. 1986. Thermal properties of foods. In Engineering Properties of Foods, MR Rao and SSH Rizvi (eds.), pp. 49-88, Marcel Decker Inc., New York.
Singh RP. 1982. Thermal diffusivity in food processing. Food Technol., 36:87-91.
Singh RP.1992. Heating and cooling processes for foods. In Handbook of Food Engineering, R. Heldman and DB Lund (eds.), pp. 247-276, Marcel Dekker Inc., New York.
Ball CO, Olson FCW. 1957. Sterilization in Food Technology: Theory, Practice and Calculation. McGraw Hill Book Co., New York.
Hayakawa K, Ball CO. 1971. Theoretical formulas for temperatures in cans of solid food and for evaluating various heat processes. J. Food Sci., 36: 306-310.
Bhowmik SR. and Hayakawa K. 1979. A new method for determining the apparent thermal diffusivity of thermally conductive food. J Food Sci., 44(2):469-474.
Rask C. 1989. Thermal properties of dough and bakery products: A review of published data, J. Food Eng., 9:167-193.
Lind I. 1991. The measurement and prediction of thermal properties of food during freezing and thawing - A review with particular reference to meat and dough. J. Food Eng., 13:285-319.
Zanoni B., Peri C. and Gianotti R. 1995. Determination of the thermal diffusivity of bread as a function of porosity. J. Food Eng., 497-510.
Magee TRA. and Bransburg T. 1995. Measurement of thermal diffusivity of potato, malt bread and wheat flour. J. Food Eng., 25:223-232.
Dickerson RW. 1965. An apparatus for the measurement of thermal diffusivity of foods. Food Technol., 19:198-204.
Carslaw HS and Jaeger JC. 1988. Conduction of Heat in Solids. Clarendon Press, 510 pp., Oxford.
Dinçer İ. 1997. Heat Transfer in Food Cooling Applications. Taylor and Francis Publishers, 399 pp., London.
Ben-Yoseph E. and Hartel RW. 1998. Computer simulation of ice recrystallization in ice cream during storage. J. Food Eng., 38:309-329.
Rahman SM. 1995. Food Process Handbook. CRC Pres, 500 pp, London.
Nesvadba P. 1982. A new transient method for the measurement of temperature dependent of thermal diffusivity. J. Phys. D:, Apply. Phys. 15: 725-737.
Geankoplis CJ. 1983. Transport Processes and Unit Operations. Prentice-Hall International Inc., 921 pp., New Jersey.
Kumcuoğlu S. 2003. Bazı gıda maddelerinin donma koşullarında ısısal özelliklerinin belirlenmesi. Ege Üniversitesi Fen bilimleri Enstitüsü Gıda Mühendisliği Anabilim Dalı Doktora tezi, 137 s, İzmir.