Table 9.

Novelties concluded in this review.

Category	Novel Areas to Explore for Future
Process	The ultrasound-based extraction at high parameters (intensity, power, amplitude, and time) for various unexplored sources (bovine, porcine).
	Water extraction along with enzymatic hydrolysis for different species is not yet explored.
	Water extraction with combined pre-chemical and post-enzymatic hydrolysis for different species is not yet explored.
	Supercritical carbon dioxide is the least researched technique among all extraction processes in terms of combinations with pre- and post-treatments, species, process parameters (pressure, temperature).
Type	Sediment method is only used to extract Type I collagen hydrolysate from a marine source (gutted fish). It is not yet explored for other types of collagen (Type II and III) and various other species (bovine, chicken, porcine).
	Glucosamine negative effects along with collagen hydrolysate are confusing and need dedicated research for clarifications.
Species	The effects of collagen hydrolysate are not thoroughly investigated for rabbits, cats, and dogs.
	Collagen hydrolysate extracted from Amur sturgeon (swim bladders) does not accumulate in the kidney and may lead to controlled urinary secretions in cats. This needs a separate area of research to discover the potential of novel sources of collagen hydrolysate in cats.
	Different chicken organs (cartilage, heads, skin) as a collagen hydrolysate species are not yet investigated for wound healing, cognitive repair, and antioxidation.