Extraction of hydrolases from Gadus morhua / Natural enzymes from slag work
The aim of the project was to extract enzymes from catfish slag for use in releasing membranes and ringworms from the liver for canning. Extensive experiments were performed using different extraction buffers and the effect of salinity, acidity, temperature and time on the activity of four enzymes. The effect of cod liver enzyme mixture on the release of ringworm and liver from the liver was also studied compared to the use of Alcalasa 2.4G used in conventional processing. The results of the project indicate that extraction methods have a broad effect on the activity of enzymes, in addition to which different enzyme activity was obtained from individual organs compared to their mixtures. The activity of the tryps was measured rather high but seemed to be controlled by the salinity of the extract solutions and the temperature. The activity of trypsin appeared to be generally comparable to the results of previous studies on trypsin activity in fish stocks. The activity of pepsin was generally very low, indicating that it is not economical to process pepsin from cod fillets, at least not under the conditions tested. It is not considered convenient to co-treat trypsin, collagenase or elastase from slag as the maximum activity of the enzymes requires different extraction conditions. The results of the project as a whole indicate that enzymes can be isolated from cod stocks in a cost-effective way using methods that only require simple equipment and cheap solutions. The results of the experiments also show that these enzymes can be used to release ringworms from the liver for canning with similar results to the methods used today. However, it is not clear whether their use is beneficial for liver processing companies as it would be necessary to change the processing process in order to achieve maximum enzyme activity.
The aim of this project was to investigate and optimize methods for the extraction of proteases from the digestive tract of cod (Gadus morhua) in order to bring about membrane dissociation of cod liver prior to canning. Homogenized viscera were extracted using various salt solutions, buffers and pH adjusted solutions at different temperatures and time. The protein concentration and activities of trypsin, pepsin, collagenase, and elastase were analyzed. Selected extraction solutions where then used for the removal of liver membranes compared to traditional treatment with Alcalase 2.4G. The results indicate that enzyme activity is influenced by the extraction methods and different enzyme activity was furthermore obtained from different organs and their combinations. Trypsin activity seems to be governed by the salt concentration of the extract solutions and temperature. The trypsin activity was relatively high and comparable with those obtained from other experiments. Next steps may include further optimization of extraction depending on the target enzyme (s), whereas the optimum conditions for the extraction of trypsin seem to differ from that of collagenase. The results indicate that the extraction of marine proteases, with the exception of pepsin, from North Atlantic cod (Gadus morhua) is potentially feasible using materials generally recognized as safe (GRAS) such as dilute, aqueous sodium chloride solutions with relatively simple equipment. The marine proteases did remove worms from the liver to a certain extent but no clear trend was observed when comparing membranes of enzyme treated livers and controls under the experimental conditions of this study.
