When you catch a fish, it is seldom eaten whole; usually some degree of processing is required, and you end up with some parts that are not your primary product. For fish fillet production, removed head, bones, skin, and intestines can often be 40–50% of the wet weight of the fish.
Some call these parts waste or discards, others call them rest raw materials or by-products. As Shakespeare wrote: “A rose by any other name would smell as sweet.” Whatever the name, this is raw material that can often be used for other purposes and give added value to new products and economic gain for the industry involved. It would be a waste to waste it (pun intended)!
Several of the papers in this issue investigate new uses for by-products from aquatic foods, including how wet or dried fermented fish silage could be used as a protein source and possibly as a probiotic ingredient for animal feed. Also, how enzymatic hydrolysates from seahorse could be a new functional food material to grow muscle cells and to enhance muscular exercise capacity.
Gelatin is an important food ingredient, and there is an increasing demand for gelatin from nonanimal origin. There is a paper in this issue showing gelatin extracted from the bones of yellowfin sole to have higher gel strength, emulsibility, and foamability, and to be a more preferable marine resource than gelatin extracted from bones of Alaska pollock. Further, recovered elastin from the skin of jumbo squid have properties that can be useful in biopolymer designs, such a food biofilms and barrier systems.
We also have a paper in this issue showing how pH and water-to-protein ratio can be used to reveal food fraud by abusive use of phosphate additives in frozen seafood products.
Finally, we have a good review paper on one of the most traditional and important seafood processing technologies—drying—and how different factors influence the complicated mechanism of lipid oxidation and how they affect oxidative stability of the dried product. Happy readings!