Given the background description of some cooking related query, summarize the question into a title

I recently tried some vacuum fried banana chips and pineapple chips from Trade Joe's. They were delicious. Does anyone know why this process helps the food retain and even concentrate the flavors? According to the article, since the frying environment is under a vacuum, this allows food to reach a fried state at ~130 C (normal atmospheric frying is ~170 C).
What makes vacuum fried food retain and concentrate the food's flavor?

I am cooking a meat stew with a delicious, fatty bunch of oxtails. Initially when browning the meat, I didn't get a sufficient amount of caramelized glaze around the oxtails and none of the fat melted into the stew.Is it possible to pull out the meat for a second sear, browning it thoroughly then reducing with the stew? Are there better ways to "save" the stew?
Can I "re-caramelize" meat after a failed braising attempt?

I have 5 - 6 lbs of sauerkraut in a crock with a water vacuum seal. I read that the first 24 - 48 hours are crucial to the success of the kraut. I also read that the kraut should develop its own liquid during this time, and that one can pour boiled water on top if it doesn't. However, I also read that it shouldn't be disturbed for a fairly long period of time. I am a bit confused. Should I check on the progress after a few days, or not?
How long should I wait before I lift the lid of my sauerkraut crock?