Can albustix paper test for the AMOUNT of protein?

YES when the protein level is so very low. NO when it is as much as in most foods.
Albustix paper are designed for testing urine, which suppose NO protein should be found. If there is some protein, then it will let the doctor know how much protein, or how bad the patient is. We are talking about traces [=very very low in quantity] of protein here. So albustix is designed to be very sensitive at low levels.
If you use it to test food, it will be very easy to overshoot the sensitivity. Say albustix can detect the difference of 1 to 5 ppm but the food you are testing have 100, 200 and 500 ppm. So the result of all 3 samples will come out as [over 5 ppm]. It is not helpful at all!
To work around the problem, you may need to do a serial dilution on your samples. That can dilute your sampes to 1,000 or even 1,000,000 times. Afterwards, the amount of protein will fall into the sensitivity range, you can then times the result with the dilution factor, and get the real protein content reading. I wonder if you will have all the equipment and technique to do that correctly, though....