Mignini insisted that Knox and Sollecito took part in the murder of Knox's British roommate Meredith Kercher and said he intended to appeal to Italy's supreme court.
Mignini complained to the Associated Press that the appeal trial "was done under unacceptable media pressure."
Judge Claudio Pratillo Hellman told the Italian news agency ANSA today that the media pressure "had absolutely no influence" on the court's decision.
"The judge is not an elected post. We do not answer to public opinion but to our conscience," the judge said.
Prattilo said he saw "the suffering of Meredith's parents," but that he also considered the suffering of Knox and Sollecito.
"I saw their anxiety and their suffering in court," he said.
The judge said that Knox and Sollecito were exonerated because there was no proof to convict them.
"We will never know if they were there or not," Pratillo said. "The court's decision to acquit them is the result of the truths that came out in the trial, but the real truth could be different."
The Associated Press contributed to this report