Review of oyster shell properties: Part II. Thermal properties

Oyster thermal properties and applications of thermal transfer to oyster shucking are discussed. Oyster shell thermal conductivity varied from 0.9 to 2.27 W/m °C, depending on the study and oyster used [Gomez-Martinez, O., Zambrano-Arjona, M., Alvarado-Gil, J.J., 2002. Imaging of subsurface defects in bivalve shells by photothermal techniques. Materials Research Society, Material Research Society Symposium Proceedings, vol. 711. Merida, Mexico; Tulshian, N., Wheaton, F.W., 1986. Oyster (Crassostrea virginica) shell thermal conductivity: technique and determination. Trans. Am. Soc. Agric. Eng. 29 (2) 626–632]. Oyster shell density varied from 1710 to 1940 kg/m3 (Tulshian and Wheaton, 1986). Releasing the oyster shell bond appears to be possible using heating or freezing. Heating is a more reliable method of shucking than freezing but the heat must be applied to the shell exterior over the muscle–shell bond without unduly heating the shell edges. Heating was applied using a water bath, white and filtered visible light, and infrared irradiation. Freezing was accomplished by an alcohol–dry ice bath, a household freezer, and by direct expansion of Freon-12. Thermal conductivity of the shell limits the usefulness of heating temperatures over 400 °C because the time to sever the muscle–shell bond is an exponentially decreasing function.