Strategies to Recover Protein and Lipids from Fish Processing By-Products

The fish processing industry has an immense opportunity for converting fish by-products into value-added products. By-products have been shown to be an excellent source of bioactive components and have diverse functional characteristics. Proteins, oil, gelatin, collagen, chitin, chitosan, silage, as well as several other economically valuable items can be produced from fish waste. Proteins (15–30%) and lipids (0.5–25%) make up a large portion of fish waste, depending on age, species, sex, season, and the environment of growth. Numerous investigations have shown that these compounds have a multitude of uses in the pharmaceutical, food, and feed industry. Conventional approaches like acid/alkali hydrolysis and solvent extraction techniques are limited owing to their lower extraction efficiency and high processing time. Microwave, ultrasound, supercritical fluid, and pulsed electric field technology are some of the novel intensified techniques that have been applied to treat fish waste, and they have proved to enhance extraction yield and functional attributes. Isoelectric solubilization and precipitation techniques have also shown high protein and lipid recovery yields. Another recent technique that has gained popularity in the recovery of isolated fish protein is pH shift acid and alkaline solubilization. This chapter provides an overview of techniques for isolation of protein and lipids, recent advancements, challenges, and their applications.