Shio-Koji Experiments: Eggs and Pork

After making the last batch of koji rice, I set some aside to make shio-koji. The recipe that I used is the following:

• 90g fresh rice koji (used the white koji spores from fermentationculture.eu)
• 13,6g salt
• 200g water

Kept it at room temperature for around 4 days and at this point was kept around 1 week in the fridge. The total salt percentage is around 4,5%.

Now, I made two main things with that: cured eggs and pork. First, the eggs. I put some shio-koji on cling film, placed a semi-soft-boiled egg on top, wrapped it tightly and tied it together with string. I got this idea from Takashi Sato. I placed them in the fridge and started to taste them after day 3. The egg white changed from a firm texture to a much creamier texture. My educated guess is that the protease produced by the koji slowly breaks down the cooked egg white. I found that people were doing this, but none of them explained why the texture changes. One instance though also reported very soft egg whites. It's definitely an interesting and unexpected texture; I'm just not sure what to do with, but it works as a bar snack or topping.

For the cured pork, I added around 80g of shio-koji to 500g of pork, along with enough salt to increase the salt content to 1%. I then put it in the fridge for around 18 hours. Afterwards, I placed it in a sous-vide water bath bringing it to 55°C, coated it in breadcrumbs, and fried it. It tasted slightly cured, a bit of koji and really good. Unfortunately, I couldn't get the breadcrumbs to stick to the pork as well as I would have liked once it had been cooked – I'm not sure why.