What are the available cheap proteins that are much less soluble than BSA

Currently, as a beginner, I'm performing solubility analysis ([with UV based spectrometry](https://tools.thermofisher.com/content/sfs/manuals/Qubit_Protein_Assay_UG.pdf)) for practices.
The protein I'm using now is [BSA](https://en.wikipedia.org/wiki/Bovine_serum_albumin). This is widely used and cheap option.


I'm now looking for a cheap negative control protein which I can use to compare with BSA.
It has to be much less soluble than BSA.


What are the good choice of proteins for that?


