Improving collagen extraction through an alternative strategy based on succinic anhydride pretreatment to retain collagen's triple-helix structure

The improvement of the extraction yield of collagen while retaining its triple-helix structure continues to represent a significant challenge for the high-value utilization of collagen. In this study, pigskin was pretreated by succinic anhydride via the chemical linking of additional carboxylic groups to epsilon amino groups with a conversion degree of 90.2% to obtain pretreatment acid-pepsin-solubilized collagen (PAPC). The pretreatment by succinic anhydride increased the tropocollagen distance from 1.39 to 1.42nm. This permitted acid and pepsin to more easily enter into the fiber clearance and, thus, improved the collagen extraction yield by 9.6%. Furthermore, X-ray diffraction, Fourier transform infrared spectroscopy, circular dichroism, ultrasensitive differential scanning calorimetry, and atomic force microscopy analysis demonstrated that the triple-helix conformation of PAPC was well-maintained. The equilibrium surface tension and isoelectric point of PAPC were 57.48 mN/m and 4.01, respectively; this suggested that the PAPC had surface activity and better solubility in a neutral pH solution. The novelty of PAPC lay in its facilitating fibroblast proliferation, and no extra cytotoxicity was introduced into the collagen after pretreatment. According to these results, our study revealed that succinic anhydride pretreatment as an alternative strategy retained the triple-helix structure of collagen and improved its extraction ratio; this might be a feasible, yet promising paradigm for the high-value utilization of collagen. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45424.