Fruit drinks and carpet go together only too well!! This tip from a commercial carpet leaner of 27 years informs that the best remedy is a bar of carbolic soap and a little warm water and rubbing. Followed by sponging. From 1978.
Apply a goo quality of non Alkaline liquid detergent mixed with a little warm water. Rub solution over the stain using a sponge or absorbent cloth. Dry well with clean cloth. Repeat with clear water. . Test for colour fastness on an obscure portion of carpet.
Removed red cordial from beige carpet by dabbing equal parts of amonia and methylated spirits. Dried between applications. Dried with the blow end of the vacuum cleaner.
For stronger stains can use a carpet cleaner shampoo if that does not work try a 50/50 peroxide solution but take extreme care as it might leave a white spot. Rinse with plenty of water after. Can dry and try again with a stronger solution if needed. Observe result and see how it goes. This is for tough stains only. Rinse with plenty of water after to remove peroxide.
If the stain is in the sun area of the carpet leave for a few weeks it may bleach out naturally.
Try and get stains out as soon as possible. Any acidic stains can burn the carpet and nothing will get those out.
If you have a little spare piece of carpet get carpet tech to cut that piece out.