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Most bird news seems to be bad news at the moment, so it's interesting to learn of some chicken and egg research being carried out in Taiwan that is using Fourier transform infra-red (FTIR) spectroscopy to analyse the structure of hen's eggshells. The work could provide information that will allow researchers to crack the problem of what to do with the vast quantities of waste shells produced by the food industry. The food industry has been scrambling for years to find a way to exploit one of its most intractable waste products - eggshells. Until now, they have been either disposed of as garbage or used for composting and animal feed. However, the shell constitutes 11% of the egg's total weight and so represents a significant waste product. Now, W.T. Tsai, J.M. Yang, C.W. Lai, Y.H. Cheng, C.C. Lin, and C.W. Yeh of the Chia Nan University of Pharmacy and Science, in Tainan, Taiwan, hoped to demonstrate that the unique structure of eggshells could provide far more innovative solutions to this waste product. The shell of a hen's eggl consists of ceramic materials in three layers - an outer cuticle, a spongy (calcareous) layer and an inner lamellar layer. The spongy and mammillary layers are made up of protein fibres bonded to calcium carbonate crystals. Physically, they are formed so that there are numerous circular pores to allow gas exchange. The cuticle has a protein (mucin) layer which is also gas permeable and protects the egg and the pores. The researchers prepared eggshell and eggshell membrane particles for analysis - shell and membrane are the two primary components of discarded eggshells. They used standard BET surface area and total pore volume measurements to show that the pore structures of the two biomaterials are of a typical Type II. This is indicative of a material with macropores, open voids, or a non-porous material. The team then used FTIR to reveal that the chemical composition of the eggshell particles is strongly associated with the presence of carbonate minerals. In contrast, eggshell membrane particles contain functional amine and amide groups because of the presence of the proteins. They confirmed the poor porosity of these eggshell particles using methylene blue uptake experiments. Related links: |
 Eggshell problem cracked? |
