An Eco-Friendly Method of Gelatin Preparation Based on Enzymatic Dehairing and Lime-Free Swelling Process

摘要

The conventional method of gelatin production generates a large quantity of wastewater, sludge and H2S gas due to the use of sulfide and lime. In this study, an eco-friendly method of extracting gelatin from animal hides was developed. The dehairing process was designed using enzymes and performed simultaneously with soaking, and the swelling process based on sodium silicate was used in the gelatin production. A comparative analysis showed that the effect of the soaking step using enzymatic dehairing was as effective as the use of sulfide. SEM analysis and proteoglycan content measurement indicated that the extent of fibre bundle opening and interfibrillar substance removal were comparable to that of the swelling process with lime when using sodium silicate. The reduction of the TKN and COD loads in the wastewater was of the order of 10% relative to the conventional swelling process, and the dry weight and organic content of the sludge generated during the swelling process based on sodium silicate were reduced by 59.62% and 41.75%, respectively. Furthermore, the gelatin extracted with this eco-friendly method possessed similar physicochemical properties, including the molecular weight, viscosity, and extraction yield. This study indicates that this eco-friendly method of gelatin preparation based on enzymatic dehairing and lime-free swelling can help to achieve sustainability in the gelatin industry.