In recent years, there has been increased interest in the production of gelatin from raw fish materials. Traditionally, gelatin is obtained using an acidic or alkaline treatment. However, these methods have some disadvantages, such as the long times for processing raw materials and the use of large amounts of water and chemicals. Enzymes could be the solution for improving the technology of fish gelatin production, due to their specificity and ability to increase the rate of collagen digestion. In this work, samples of gelatin from cod skin were obtained using enzymes of bacterial and animal origins. The use of enzymes reduced the duration of extraction by 40%, and yield of the product was increased from 51% to 58–60%. The dependence of the main components’ content of secondary structure of gelatin and its rheological and thermal properties on molecular weight was also established. The gelatins obtained without enzymes and with protosubtilin were shown to have the most desirable characteristics, namely of the highest molecular weights and the highest proportion of ordered structures. The morphology, supramolecular structure and colloid properties of gelatin extracted from cold-water codfish skin with commercial mammalian and fish gelatins have been compared. The extracted codfish gelatin is much closer to the mammalian one in terms of thermal stability and strength of structural network. This research was funded by the Russian Science Foundation, project No. 23-64-10020.

Svetlana Derkach has completed her PHD from Mendeleev university of chemical technology, Moscow, Russia. She is the chief researcher of laboratory of chemistry and technology of marine bioresources, Murmansk arctic university, Russia. She has over 200 publications that have been cited over 1600 times, and his publication h-index is 21. Her research interests: colloid chemistry of biopolymer systems, proteins, polysaccharides, surfactants, gels, emulsions, rheology, food technologies. She has been serving as a member of the organizing committee of several international conferences and a guest editor and a reviewer for several reputed journals.