What is the science behind velveting meat? [duplicate]

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• How does velveting work? 2 answers

In a lot of Chinese restaurants, the beef you get in stir fries are extremely tender.

I'm aware that they use a technique referred to as 'velveting' the meat, which involves using corn flour and possibly eggs.

My question is, what is the science behind this? How can flour and egg turn a normally tough and chewy piece of beef to a 'melt in your mouth' experience?