沙壳蛋钙化壳的结构特征

Structural Characterizations of Calcified Pimpled Chicken Eggshells

为了深入研究蛋壳品质的形成机理,本文通过比较沙壳蛋和正常蛋钙化壳中粗灰分含量,以及沙壳蛋中砂质壳部和正常壳部超微结构和方解石晶体特征,结果表明:沙壳蛋砂质壳部粗灰分(无机物)含量极显著低于正常鸡蛋壳(P<0.01)。沙壳蛋的砂质壳部厚度明显低于正常壳部;砂质壳部乳锥层的乳突密度小于正常壳部,但未达统计学显著性(P>0.05),砂质壳乳突更圆钝、间隙更大,乳突中气孔明显更多;此外,砂质壳部垂直晶体层质地疏松,有颗粒状或块状堆叠,其下方的棱柱层中气孔明显减少。所有蛋壳样品外表面(104)晶面衍射峰强度高于内表面,其中沙壳蛋正常壳部以及正常鸡蛋壳的增长幅度明显高于砂质壳;此外,不论是内表面还是外表面,正常鸡蛋壳和沙壳蛋正常壳部晶粒均大幅度地小于砂质壳部,沙壳蛋砂质壳部和正常壳部内外表面的晶粒大小相近,而正常鸡蛋壳由内向外有较大幅度的减小。根据上述结果可得出,在鸡蛋壳形成过程中,砂质壳部晶化界面的有机组分诱导晶核形成的效率可能更低,晶粒间有机组分分布的持续性更差;此外,生物晶体的生长及优势取向或许不单纯取决于有机组分的量,可能还依赖于有机组分的构成、结构属性等。

In order to probe into the regulating mechanisms for eggsheU quauty, mls stuuy lnvc^u~,~ in calcified shells between pimpled eggs and normal eggs, the ultrastructures and crystal structures between pimpled area and normal area of pimpled eggshells. The results showed that the crude ash （inorganic components） content in pimpled areas of pimpled eggs was significant less than that in normal shells （P〈0.01）. The thickness of pimpled area was greatly less than the non-pimpled area of the same eggshells; the mammillary knob density in the pimpled mammillary layers was also low （P〉0.05）; the mammillary knobs in pimpled area were more blunted, the pore density in them was larger, and the gaps between knobs were also larger; furthermore, the textures of vertical crystal layer of pimpled area were more crushable, and the pore density in the pimpled palisade layer was much lower. Compared with pimpled area, the amplification of diffraction peak corresponding to the（104） orientation in both non-pimpled area and normal eggshell outer surface was much greater than inner surface; furthermore, regardless of inner or outer surface, the crystal cone sizes in both non-pimpled areas and normal eggshells were much smaller than that in pimpled areas; in both non-pimpled and pimpled areas, the crystal cone size between inner and outer surfaces was nearly equal, while the crystal cone size in normal shell inner surfaces was much larger than that in the outer surfaces. Above all, we speculated that the nucleation efficiency for the organic matrix at the crystallization surface might be weaker in pimpled area, and the organic matrix distribution between crystal cones might be more inhomogeneous; furthermore, it was possible that both crystal growth and orientation might depend on not only organic matrix quantity but also its constituents and fine structures.