Effect of concentration of gelatin
The function of gelatin is to stabilize and protect the catalytic
activity of the enzymes in dried form, and to control the diffusion
rate of the sample solution to match the overall color-forming process.
Fig. 2 displayed the effects of gelatin concentration, optimized
concentration of gelatin is 0.625%. According to our observation,
with the lower concentration of gelatin the red color would expand
fast with the water but with the higher concentration the water
would not pass through and stopped at the bottom of the detection
zone. They are both unfavourable for the color-forming.