Evaluation of drying-grinding and wetting-grinding mediated fabrication of pork skin functional protein powders: the underlying mechanism responsible for superior properties and functionalities

The concept of healthiness and sustainability have triggered consumers into choosing healthier food, especially “clean-label” products. Porcine skin is a natural “clean-label” raw material, and direct usage of whole pork skin as an additive has been proven as an efficient way to deal with the by-product issues and also satisfies the “clean label” demands of consumers. However, efficient approaches to convert bulk skin into handy powders in a green-fabrication manner while maintaining its unique properties have yet to be fully investigated. Herein, we provided two green approaches, drying-grinding, and wetting-grinding, to prepare pork skin functional protein powder (FPP), and their chemical composition, structure, properties, stability, and functionality are systematically investigated. Specifically, FPP prepared by two methods exhibit similar chemical composition and great thermal stability. Notably, FPP prepared by drying-grinding method is superior in flow ability, water dispersion, and texture properties of FPP gels as compared to wetting-grinding method. Structural analyses revealed that the superior properties of FPP prepared by drying-grinding method depend on the intrinsic natural triple helix structure of collagen. Overall, this work revealed the underlying key factors for the preparation of FPP with excellent properties, and highlighted that the FPP prepared by drying-grinding method is more suitable for practical application as “clean-label” additives in the food industry.