Preparation and thermal stability of collagen from scales of grass carp (Ctenopharyngodon idellus)

Grass carp (Ctenopharyngodon idellus) scales (GCS) was swollen in water and treated with microwave for 2 min, followed by decalcifying with 8% aqueous citric acid solution. The collagen of GCS was then prepared by limited pepsin digestion with a yield of 25.64% on dry weight basis. SDS-PAGE, FT-IR and amino acid composition analysis indicated that the pepsin-solubilized collagen from GCS was typical type I collagen, consisting of three different alpha chains, alpha(1), alpha(2) and alpha(3). The thermal stability of pepsin-solubilized collagen from GCS was studied using viscometry, circular dichroism (CD) and Raman spectroscopies. The denaturation temperature (T-d) of collagen solution was 32 degrees C determined by viscometry. CD spectra analysis showed that the Td of GCS solution was between 35 degrees C and 40 degrees C, and further confirmed by Raman spectra. Thus, a large amount of collagen could be obtained from GCS and the preparation method is safe and time-economizing, and GCS will have potential as an important collagen source for use in various industries.