1) After a Korean exits prison, a white block of tofu, nothing else, is the first thing that they are supposed to eat. By doing this, they have a better chance to live a life of purity from that point after. 

2) My Korean mother told me about the “folk item / food” that is tofu because she said she wants me to know that even if I make a grave mistake, I will always have a chance at redemption if I assume the right mentality. 

3) My Korean mother told me this when I was eating dinner with my family. I asked if there are any Korean foods that have a traditional / folk significance, and after a moment of thinking she came up with the above example.

4) This practice started in the prisons of the Joseon dynasty, but is now seen in modern-day Korean noir films. Perhaps tied to its longevity is the fact that tofu is already such a staple food for Koreans. Also, in prison they only give inmates bean rice for food (no tofu). Tofu is also made from beans, but it is an elevated form of bean to the one included in rice in prisons.