Interview notes would not have to be turned over to the candidate. They are personal opinion of the interviewer even if they mention the candidate. GDPR protects that data: you may not disclose it because it would violate the rights of the interviewer.
Most people seem to interpret the directive to say that, because the interview notes constitute "any information relating to an identified or identifiable natural person", they are personal data of the person being interviewed?
Under the existing Data Protection Directive these notes are subject to people making a Subject Access Request.
Probably you can redact it so that it doesn't include the actual names of which interview panellist said what.