Main Article Content
A new and efficient microwave heating method was developed to extract intact Type I collagen from bovine limed splits. Orthogonal experiment was conducted to optimize the parameters of extraction, and the extraction yield was measured by ultraviolet spectra (UV). The hierarchical structures of the obtained collagen were determined by amino acid analysis, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), UV, Fourier transform infrared spectra (FT-IR), circular dichroism spectra (CD), fluorescence spectra (FL) and ultra-sensitive differential scanning calorimetry (US-DSC). The results indicated the optimal conditions for this microwave assisted extraction were 37°C for 7 h by using solid to liquid ratio of 1:45. The resultant yield of collagen was 14.35% under the optimal conditions, which is 1.5 times higher than that obtained by the control water bath-heating method. Amino acid analysis, UV and SDS-PAGE revealed that the primary structure of collagen extracted with microwave assistance was type I collagen. Although the extraction yield was promoted drastically with microwave assisting, the secondary structure of the collagen involving triple helix still maintained according to FT-IR, CD, FL and VP-DSC results. In brief, microwave irradiation could be a new routine for collagen extraction with advantages of fast and effective. Moreover, this study might offer a potential choice for utilizing hide or skin limed split wastes.