THIS DOES NOT MEET YOUR PRICE POINT(~$330), but I would be remiss, if I didn’t show you.
STX International STX-DEH-1200W-XLS Dehydra Commercial Grade Stainless Steel Digital Food Dehydrator - 10 Trays - 1200 Watts - 165 Degree Fahrenheit - Jerky Safe with 15 Hour Timer https://www.amazon.com/dp/B007QCXU5M/ref=cm_sw_r_cp_api_glt_fabc_T20XEQXMWFS2VV84ESZZ?_encoding=UTF8&psc=1
This thing is a beast. I have no complaints thus far, but I barely use it compared to the people creating these awesome projects on this subreddit.
there is no protein lost. it doesn't evaporate -- only water.
FYI i've had this dehydrator for years and highly recommend it:
https://www.amazon.com/STX-International-STX-DEH-1200W-XLS-Commercial-Dehydrator/dp/B007QCXU5M
imo you don't want any plastic in a dehydrator.