Banana is a term for an Asian person living in a Western country (e.g., an Asian American) who has lost touch with the cultural identity of his or her parents. The term is derived from the fruit banana, which is "yellow on the outside, white on the inside". It may be used as a pejorative term or as a non-pejorative term.
Chinese context
This term is related to the Cantonese slang Jook-sing, which refers to an overseas Chinese person who was born in a Western environment or a Chinese person who more readily or strongly identifies with Western culture than traditional Chinese culture.
References
Banana (slur) Wikipedia(Text) CC BY-SA