摘要：Methods of gelatin extraction from nila fish ( Oreochromis nilotichus ) skin were studied using acid treatment (acetic acid or citric acid) at various concentrations (0, 0.05, 0.10, 0.15, 0.20 and 0.25 M) and soaking times (0, 1, 2, 3, 4 and 5 h). Gelatin extracted from nila skin treated with 0.10 M acetic acid for 2 h produced the highest yield (25.33%) with a gel strength of 346.16 g bloom and a molecule size distribution of 38-241 kDa. Gelatin extracted from the skin treated with 0.05 M citric acid for 1 h resulted in a yield of 21.09% with a gel strength of 134.52 g bloom and a molecule size distribution of 23-145 kDa. Gelatin extracted by both acids had similar infra-red absorbance spectra, ranging from 1640 to 1239 cm-1. However, gelatin from nila skin treated with 0.10 M acetic acid for 2 h produced gelatin with a more homogenous molecular microstructure than nila skin treated with 0.05 M citric acid for 1 h.
