Abstract: The invention relaates to the production of collagen fibers by comminuting collagen containing tissues, drying the comminuted product and milling the dried material while maintaining the temperature sufficiently low to prevent substantial conversion of collagen to gelatin. The collagen fiber product is particularly useful for restructuring poorly textured meats, mechanically recovered meat products, offal, fish, fish products and other protein products to improve textural properties, water retention, fat retention, eating quality, juicines, succulence, shape, size retention and protein content.