from sparknotes:
The title of the novel Oranges are Not the Only Fruit demands an explanation that can only offered through analyzing the many appearance of oranges in the story. On the broadest level, these oranges represent the dominant ideology that pervades the world in which Jeanette lives. Whenever Jeanette feels uncertain about something, her mother offers her oranges. In some circumstances, these oranges appear to strictly represent heterosexuality. But generally they represent more than just the dominance of heterosexuality; they represent the entire repressive system that Jeanette's mother espouses. When Jeanette sees Melanie after their relationship has ended, Melanie offers her an orange but Jeanette refuses to take it. Her refusal represents her refusal to succumb to the ideas of the status quo as has Melanie. Jeanette wants to remain true to her own principles and decides to head out into the world, but refuses to ever sell oranges. Throughout the entire book, Jeanette's mother believes that oranges are the only fruit, but Jeanette can see that there are others. Heterosexuality is just one way of living life, but there are many others that should be equally valued.
THere is a pretty comprehensive analysis on sparknotes - check it out
http://www.sparknotes.com/lit/oranges/co…