I prepared a 100 ml solution of HCl and NaCl according to the instructions I've referred to in an earlier post in this thread, and according to the instructions by Kephra for calculating the correct amount of HCl to get a pH of 1. The pH was then tested with pH-paper to confirm that it was 1. I used a HCl with a 30% concentration.
The 100 ml solution was heated to 37 degree Celsius then divided in two x 50 ml for two tests.
In the first test I added 1 ml of a previously made batch of 250 ml of 500 ppm (125 mg) colloidal silver that where the reduction was made with 1 ml Cinnamon extract and capped with 200 mg Gelatin.
http://oi59.tinypic.com/10ge2rs.jpgThe second test is similar, but it was a batch of 250 ml of 400 ppm (100 mg) colloidal silver that was reduced with 160 mg Maltose and capped with 200 mg Gelatin.
http://oi61.tinypic.com/35lhys8.jpgAs can be seen, both tests was clear, and they are both still clear now after ~30 minutes, which should confirm that the gelatin protects the nanoparticles.
I have ordered Pepsin, so that I should be able to prepare better test solutions, as Pepsin degrades proteins (which is one component in Gelatin). And I will make more tests then to confirm whether the's enough of Gelatin to withstand the Pepsin.
But this should at least confirm that Gelatin is a good capping agent for withstanding the gastric acid and salt down to a pH-level of 1.