DOHA (AFP) - A Qatari appeals court on Sunday acquitted a United States couple charged with parental neglect leading to the death of their adopted daughter.

Matthew and Grace Huang were arrested in January 2013 after the death of their eight-year-old daughter Gloria, who had been adopted from an orphanage in Ghana.

The couple, who are of Asian descent, were initially accused of starving to death their child to sell her organs, but were later jailed for three years on the charges of parental neglect.

On Sunday the appeals court ruled the couple were not guilty and said they were free to leave Qatar, based on witnesses' accounts that Gloria was "not neglected in leading a normal life".

"Grace and I want to go home and be reunited with our sons," said Mr Huang, describing the judicial process in the Gulf state as "long and emotional".

"We have been unable to grieve our daughter's death but we want to thank the judge for today's decision," he told reporters outside the court.

"We're looking forward to returning to the US," he said.

The witnesses had testified that they saw Gloria eating one day before her death, the presiding judge said.

"This negates the charge that she was prevented from eating, a charge that the court of first instance used as a base for its initial ruling," the judge said.

The couple were released in November last year pending trial, but the court denied their request to leave the country to join their other two adopted children in the United States.

Both adoption and multiracial families are rare in Qatar, a conservative Gulf Arab emirate, and the family's supporters maintain the Qatari authorities misunderstood the Huangs' situation.

The public prosecutor had pushed for the death penalty for the Huangs.

In addition to imprisonment, the lower court had ordered the couple to pay a fine of 15,000 riyals (S$5,200) each and to be deported after serving their sentence.