Science Buddies: "Ask an Expert"

Hi, I'm interested in conducting this experiment for my IB chemistry internal assessment. I will try to compare the protein content of different plant-based sources: tofu, tempeh, and wheat gluten (aka seitan).

I know that I can coagulate the tofu protein from soy milk. But how do I find the protein content of the tempeh and seitan (not just using the nutritional facts on the package, I will use that to determine my percent error). This also has to be an intermediate/advanced experiment. I will be doing this in my school's chemistry lab under the supervision of my chem teacher.

Thanks.

Hello aascience12,

So if you are looking to determine the protein content of both tofu and Tempeh you can use the same method you discussed with the tofu. The tempeh, however, will require you to first hydrate it then crush it and take the liquid obtained and precipitate off that. you may also want to used soybeans alone as a control because are soy products. When separating the proteins in in seitan you will again need to suspend it in a liquid most likely water due to its pH. The issue comes when you try to separate the protein for the spices which would require you to dissolve them in acid and use a separatory funnel or column, and a rotary evaporator to remove them, however, I am not sure what lab equipment you have access to, and the process could damage the integrity of the proteins if the acid is too strong.