Lemons, limes and other citrus fruits are some of the most acidic fruits and, therefore, some of the most tart or sour-tasting. Kiwifruit, blackcurrants and raspberries are other familiar fruits that have a similar tartness. Granny Smith apples are also more tart compared to other types of apples.
According to Chinese traditional medicine, the sour or tart fruits are beneficial to the liver and gallbladder. These more acidic fruits are considered the most detoxifying for the body. Pineapples, plums, grapefruit, tangerines and even sour tomatoes are good for this purpose. Sour fruits also have fewer calories than sweet ones because they have less natural sugar or fructose. This is helpful for those trying to lose weight because eating too much sweet food can lead to weight gain. Eating sour fruit provides vitamins without extra calories and sugar.
Ascorbic acid, better known as vitamin C, is also plentiful in citrus fruits and vegetables. Vitamin C helps the body maintain a strong immune system, which is why it is useful for fighting colds. Women and men need at least 75 or 90 milligrams per day respectively, according to USDA dietary guidelines. The guava is actually the fruit that is highest in vitamin C, with 188 milligrams in just a half cup of this fruit.