# Marine Gelatine from Rest Raw Materials
## 3 Production Strategies for Gelatine  
Industrial production of gelatine is a well-known process, and in general, includes raw material washing, pre-treatment, extraction, and purification followed by drying and packing of the final product. Although the parameters of the steps vary greatly between manufacturers, the choice of raw material dictates the pre-treatment procedure and influences the complexity of production. Unlike bovine and porcine sources, fish skins used for industrial production of gelatine are often not subjected to harsh pre-treatment, due to weaker bonds in this type of collagen. A simplified scheme of fish gelatine production is shown in Scheme 1[38].  
To properly assess the economic feasibility of industrial-scale fish gelatine production, numerous factors, such as raw material availability and price, production costs, and final product price margin, need to be accounted. Although fish gelatine amounts to only a fraction of worldwide gelatine manufacturing, the high quantities of by-products generated by fisheries represent a potentially lucrative opportunity for its market increase. Recent work of the Trash2 Cash project (2011-2015) in Denmark has undertaken considerable research concerning the economic feasibility of gelatine production from fish sources [39; 40]. Findings from this project show that the market for fish gelatine and fish collagen hydrolysates is small, (2000 to 3000 tons per year), and that prices of final products vary from 10 to 15 \(\ell\) per kg, depending on traceability, degree of hydrolysis, taste, and purity [39]. As a part of the same project, financial and economic aspects of construction of a fish gelatine plant have been evaluated. Using a \"greenfield\" model (model which assesses costs of constructing a plant from nothing at starting point--i.e., \"green field\") estimates of investments, operating costs and revenues were made [40]. In general, the estimation showed that, when major equipment and variable costs are taken into account, the final revenue would operate with a financial margin of almost 50%, provided that the operation of the plant is at full capacity. This operating revenue is estimated with fish gelatine prices set between 10-12 \(\epsilon\)/kg, in the case that the raw material (fish skin) costs are 2.25-2.5 DKK (0.30-0.34 \(\epsilon\)) per kilogram and yield of produced gelatine is 10% [40]. These estimations indicate that market prices of raw material and produced gelatine have the most pronounced influence on the final operating revenue. However, the expected yield of gelatine extraction can also be a major factor for considerations since it is dependent on multiple variables, such as raw material quality, composition, and origin. Having this in mind, careful optimization of production steps (pre-treatment, extraction) has to be taken into account for future production planning.  
During gelatine production, the insoluble native collagen must be pre-treated before it can be converted into a form suitable for extraction [7; 21]. This is routinely done by heating in water at temperatures higher than 45 \({}^{\circ}\)C. A chemical pre-treatment is intended to break non-covalent bonds in order to disorganize the protein structure, and produce adequate swelling and collagen solubilisation [7; 17]. The production process variables (pH, temperature and time) during pre-treatment and extraction steps also have a significant influence on the collagen denaturation, which, along with the animal species and tissue type, affects the properties of the obtained gelatine [21; 29].