Eco-friendly extraction of collagen from beluga sturgeon skin using ultrasound-assisted deep eutectic solvents:...

The current study aims to extract collagen from the skin of beluga sturgeon (Huso huso) using deep eutectic solvents combined with ultrasound as a green recovery method. It evaluates both the yield of the extraction process and the structural and physicochemical properties of the extracted collagen. The extraction utilized deep eutectic solvents, including choline chloride-glycerol, choline chloride-urea, and choline chloride-acetic acid, all at a molar ratio of 1:2. Among these, the choline chloride-acetic acid solvent yielded the highest extraction rate at 20.28 % and was selected for further ultrasound treatments lasting 5, 10, 15, and 20 min, with a power setting of 400 W. Ultrasound treatment significantly enhanced collagen extraction yield, with a 10-min treatment achieving the highest efficiency at 24 %. SDS-PAGE analysis confirmed the presence of type I collagen, indicating no structural changes during extraction. FTIR analysis showed that the triple helical structure of ultrasound-treated collagen was preserved throughout the process. Longer ultrasound treatment durations improved collagen purification, resulting in higher protein and total amino acid content. Additionally, ultrasound application enhanced thermal stability, water holding capacity, and gel formation power, with peak values observed during a 15-min treatment. In summary, extracting collagen from beluga skin using deep eutectic solvents in combination with ultrasound is an effective method for enhancing both yield and functionality of the resulting collagen.