||Seafood such as fish, shellfish, and squid are a unique source of nutrients. However,
many marine processing byproducts, such as viscera, shells, heads, and bones, are discarded,
even though they are rich sources of structurally diverse bioactive nitrogenous components.
Based on emerging evidence of their potential health benefits, these components show
significant promise as functional food ingredients. Fish waste components contain significant
levels of high-quality protein, which represents a source for biofunctional peptide mining. The
chitin contained in shrimp shells, crab shells, and squid pens may also be of value. The
components produced by bioconversion are reported to have antioxidative, antimicrobial,
anticancer, antihypertensive, antidiabetic, and anticoagulant activities. This review provides an
overview of the extraordinary potential of processing fish and chitin-containing seafood
byproducts via chemical procedures, enzymatic and fermentation technologies, and chemical
modifications, as well as their applications.