Effect of temperature on the morphology and crystal structure of sea bass scales

This paper focuses on the characteristics of the sea bass scale before and after heat treatment. The sea bass scale was washed with water several times to remove tissue and contamination. The sea bass scale was boiled at 200 ˚C for 1 h, washed with water and dried. The sea bass scale was ground with agate mortar until powder. The sea bass scale powder was studied on weight loss by thermogravimetric analysis ( TGA) . The results showed that the moisture and some organic compounds were decomposed around 300 ˚C, while the gelatin and organic compounds were decomposed around 600 ˚C. At 900 ˚C, the water and some organic crystal structures were decomposed. From the TGA results, the temperatures at 300, 600, 900 and 1,200 ˚C were used to heat the sea bass scale. The crystal structure, functional group and morphology of sea bass scale powder before and after heating were investigated by X- ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR) and scanning electron microscope (SEM), respectively. The results showed that the crystal structure of raw sea bass scale has an amorphous phase of hydroxyapatite. At 900 ˚C, the crystal structure of the sea bass scale showed a pure phase with high hydroxyapatite. Moreover, the crystallinity of hydroxyapatite increased with increasing temperature heat treatment. These results were confirmed with FTIR and SEM results. This research demonstrated the sea bass scale from food processing as a precursor for synthesizing pure hydroxyapatite.