**Junde Chen 1,\*, Min Li 2,\*, Ruizao Yi 1, Kaikai Bai 1, Guangyu Wang 1, Ran Tan 1, Shanshan Sun <sup>1</sup> and Nuohua Xu <sup>1</sup>**


Received: 28 November 2018; Accepted: 27 December 2018; Published: 4 January 2019

**Abstract:** Collagen is widely used in drugs, biomaterials, foods, and cosmetics. By-products of the fishing industry are rich sources of collagen, which can be used as an alternative to collagen traditionally harvested from land mammals. However, commercial applications of fish-based collagen are limited by the low efficiency, low productivity, and low sustainability of the extraction process. This study applied a new technique (electrodialysis) for the extraction of *Takifugu flavidus* skin collagen. We found electrodialysis to have better economic and environmental outcomes than traditional dialysis as it significantly reduced the purification time and wastewater (~95%) while maintaining high extraction yield (67.3 ± 1.3 g/100 g dry weight, *p* < 0.05). SDS-PAGE, amino acid composition analysis, and spectrophotometric characterization indicated that electrodialysis treatment retained the physicochemical properties of *T. flavidus* collagen. Heavy metals and tetrodotoxin analyses indicated the safety of *T. flavidus* collagen. Notably, the collagen had similar thermal stability to calf skin collagen, with the maximum transition temperature and denaturation temperature of 41.8 ± 0.35 and 28.4 ± 2.5 ◦C, respectively. All evidence suggests that electrodialysis is a promising technique for extracting collagen in the fishing industry and that *T. flavidus* skin collagen could serve as an alternative source of collagen to meet the increasing demand from consumers.

**Keywords:** skin collagen; electrodialysis; thermal stability; *Takifugu flavidus*
