Enhancing the value of rabbit bone by-products via hydrochloric acid-aided gelatin extraction: optimization and characterization

Rabbit bones, a byproduct of the meat industry, are a potential source of gelatin because of their high collagen content. Compared with bovine, fish, and poultry bone gelatin, studies on rabbit bone gelatin remain limited, particularly regarding extraction process optimization and comprehensive physicochemical characterization. Previous studies have primarily focused on acid concentration, whereas the combined effects of pretreatment duration, extraction temperature, and extraction time on gelatin quality and extraction efficiency are still poorly understood. Therefore, this research aimed to determine the optimal conditions for rabbit bone gelatin extraction via acid pretreatment with response surface methodology. Box–Behnken design (BBD) was used to evaluate the effects of pretreatment time, extraction time, and extraction temperature on gel strength and yield, and the physicochemical characteristics of the extracted rabbit bone gelatin were also analyzed. The optimum conditions for rabbit bone gelatin extraction were 6 days of HCl pretreatment, 8.79 h of extraction, and an extraction temperature of 70 °C. Under these conditions, the gel strength produced was 281.53 bloom, and the yield was 11.86. The physicochemical properties of the rabbit bone gelatin were comparable to those of commercial gelatin, with 86.3 protein content, 0.52 ash, 6.9 moisture, 1.28 fat, 10.1 cP viscosity, and a pH of 3.92. The distinctive A, B, I, II, and III amide peaks were found in the FTIR spectra. Amino acid profiling revealed that glycine (20.88) and proline (10.42) were the dominant units. The α-chain was detected via SDS-PAGE analysis. This study provides valuable insights into the rabbit bone gelatin extraction process, demonstrating that the optimized extraction conditions not only enhanced gelatin quality, but also promoted the valorization of rabbit bone by-products as a sustainable alternative gelatin source for food, pharmaceutical, and industrial applications. This journal is © The Royal Society of Chemistry, 2026.