The point of the posts was that there are other ways to detect chitinase. A quick search showed this one using elisa instead of chromatogrophy. If you check the background on how the kits were developed, there you might find information useful to your project.
The point of the question was not to replace a recommendation of one complex method that is only sold to institutions with another of similar complexity and exclusivity, nor was the question about how to detect chitinase. The question is if measurements of the precise chitinase activity in units per milliliter have been done on chitinase-rich foods in their natural state, and if so, the numbers.
And when you claimed that it "probably would not work", I thought that you meant that you did not think using the chitinase content in crude foods to degrade chitin would work. That was why I mentioned that it should be sufficient to degrade the chitin of at least some organisms as a pest defense since evolution allows the chitinase to exist in the foods despite its cost, and why I asked if there are simple ways of concentrating the chitinase to a higher concentration than in the crude food. And by simple I mean DIY simple, not "buy expensive stuff".