Comparative evaluation of fish gelatin production via acid hydrolysis, enzymatic process, and hydrothermal: Product quality, environmental impacts, and sustainability trade-offs

Gelatin derived from fish by-products represents a sustainable alternative to mammalian sources in food and pharmaceutical sectors. This study investigated the efficacy of three extraction methods—acidic, enzymatic, and hydrothermal—for producing gelatin from byproducts of fish industry. The resulting gelatin was characterized based on physicochemical properties: gel strength, as primary indicators of industrial functionality and processing efficiency: yield. Furthermore, the environmental sustainability of each method was quantified via Life Cycle Assessment (LCA) using the ReCiPe (H) midpoint and endpoint approaches, focusing on ecosystem quality and human health indicators. Results indicated that the hydrolysis mechanism significantly influenced both functional characteristics and environmental performance. While acidic extraction yielded the highest gel strength, it was characterized by lower recovery rates and a substantial environmental footprint. Conversely, hydrothermal extraction emerged as the most balanced approach, demonstrating the lowest environmental burden while maintaining a competitive yield (13.11 ± 0.74%) and robust gel strength (275.3 ± 2.12 g bloom). These findings suggest that hydrothermal processing is a viable, eco-friendly alternative to conventional acid-based methods for the industrial-scale valorisation of fish-processing waste.