The growing interest in valorizing industrial by-products has led researchers to focus on exploring different sources and optimizing collagen extraction conditions over the past decade. While bovine hide, cattle bones, pork, and pig skins remain the most abundant collagen sources, there is a growing trend in the industrial utilization of collagen from non-mammalian species. This review explores alternative marine collagen sources and summarizes emerging trends in collagen recovery from marine sources, with a particular focus on environmentally friendly methods. Additionally, this review covers the colloidal structure-forming properties of marine collagens, including foam, film, gel, and emulsion formation. It also highlights the potential and important applications of marine collagen in various food products. Based on the currently reported marine sources, collagens extracted from fish, jellyfish, and sea cucumbers were found to have the highest yield and mostly comprised type-I collagen, while crustaceans and mollusks yielded lower percentages of collagen. Traditional extraction techniques isolate collagen based on acetic acid and pepsin treatment, but they come with drawbacks such as being time-consuming, causing sample destruction, and using solvents. Conversely, marine collagen extracted using conventional methods assisted with ultrasonication resulted in higher yields and strengthened the triple-stranded helical structures. Recently, an increasing number of new applications have been found in the food industry for marine collagens, such as biodegradable film-forming materials, colloid stabilizers, foaming agents, and micro-encapsulating agents. Furthermore, collagen is a modern foodstuff and is extensively used in the beverage, dairy, and meat industries to increase the stability, consistency, and elasticity of products.
Graphical abstract
