Structure and physical properties of gelatin from bovine bone collagen influenced by acid pretreatment and pepsin

Effects of different acids and pepsin on the properties of gelatins extracted from bovine bone collagen were investigated. Pretreatment of bovine bone by different acids (hydrochloric acid, acetic acid, and citric acid) with and without pepsin was performed at 70 degrees C for 7 h to extract gelatin. Under the different acid treatments, the yield of gelatin was significantly different (hydrochloric acid, 4.76%; acetic acid, 4.26%; citric acid, 6.00%). Compared to no pepsin incubation group, bovine bone collagen treated with pepsin presented a higher yield (P < 0.05). Scanning electron microscopy analysis showed that citric acid disrupted more of the collagen structure compared with acetic acid and hydrochloric acid. Raman spectra revealed that all extracted gelatins had the similar secondary structure. Rheological analysis indicated that gelatin extracted with citric acid exhibited the highest maximum elastic modulus, gelling and melting temperature. Overall, the gelatin yield was affected by the type of pretreatment acid and more optimal gelatin extraction and gel properties were obtained when citric acid was used for extraction. Collagen pretreated with acid and pepsin was more efficiently extracted for gelatin compared to treatment without pepsin. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.