Sustainable gelatin extraction from poultry skin-head-feet blend: An ultrasound-assisted approach

The study investigated gelatin extraction from chicken skin-head-feet (SHF) blend using conventional and ultrasound-assisted methods with food-grade acetic and citric acids. Ultrasound pretreatment was introduced as an intervention in the extraction process, eliminating the need for alkali hydrolysis and significantly reducing the processing time. The gelatin yield, gel clarity, textural parameters, and functional properties were noticeably improved with ultrasound pretreatment. Higher (p< 0.05) solubility was observed in ultrasound-treated gelatin relative to traditionally extracted gelatin at different pH levels. Fourier Transform Infrared (FTIR) spectra revealed characteristic bands corresponding to Amide A, B, I, II, and III. Ultrasonication enhanced α-helical structure by reorganizing protein conformations and stabilizing α-helix regions. The rheological properties, gel strength, and viscosity significantly (p< 0.05) increased with ultrasound-assisted extraction. The SDS-PAGE profile of gelatin was compared with the commercial pork skin gelatin and found to possess two distinct α-chains (α1 and α2) and β chain. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry revealed the presence of collagen α1 and α2 chains as major components. This sustainable approach transformed poultry waste into a valuable resource, fostering the recovery of gelatin with improved functional attributes.