Fun Food Trivia - Guess the Mystery Food

TRIVIA QUESTION: Roughly the size of a small plum, I am thought to resemble a miniature orange. Grown in China since ancient times, I am mentioned in a piece of Chinese literature dating back to 1178 AD. My flavor is an intriguing combination of sweet and tart. You'll often find me served during the Chinese Spring Festival, as my name in Chinese signifies gold, and I symbolize a prosperous start for the new year. What am I? Find out the answer.