I’m not sure but I think that you make this matter more complicated than it really is.
As mentioned by Jiang Kunpeng, the point is that it is not so much that the fat content increases but the protein content decreases because of the degradation of (part of) the proteins present.
An example might help:
Suppose you have 5 gram fat and 5 gram protein then obviously you have 50% fat and 50% protein.
Suppose that after the protease degradation process 1,5 gram of protein is left you have 5 gram fat and 1,5 gram protein (meaning 76,9% fat and 23,1% protein).
Indeed it seems that the fat content increases but this solely because the protein content decreases (it is all relative as expressed in percentages, but the absolute mass of fat remains the same).
Percentage is indeed relative unless you state on what 100% represents actually in terms of absolute measurement (in your case it is the total mass of the sample which is obviously varying with the protease treatment). In your experiment you double the percentage of fat which means that half of the initial sample mass was protein susceptible to protease treatment.
Rob Keller Thank you Dr. Keller. I am still confused. The sample contain about 26% Fat but after Protease activity fat content rise up to 53%. I havn't analyzed protein content yet just focused on fat. The fat extraction was done by soxhlet apparatus.
Is it containing any enzymatic activities by itself? I don't think so. If no there is no way to get fat from aminoacids resulting from protease digestion.
But do you actually get more fat in term of mass content or is it just the proportion of fat which is getting bigger?
Regardless of what might the final cause for your observation, your final percentage seems to be too high.
Two explanations:
The most likely explanation I can come up with is that your extraction (after protease activity) becomes more effective. Possibly because fatty acid binding proteins (being partly degraded) release the fatty acids bound to the protein fraction. Still does not solves the fact that your percentage seems to be too high.
The other explanation might be that a ‘simple’ weight determination after ether extraction is not accurate enough and that your procedure revealed that protease treatment extracts non-fat components as well. You now count with the fat content components that are non-fat, but that the actual fat content is lower (perhaps you should analyse your fat content).