From the Oxford dictionary:
used to refer to an attitude in which someone adopts a negative attitude to something because they cannot have it themselves:
government officials dismissed many of the complaints as sour grapes
Is there an equivalent or similar expression in Italian?
This question has been already asked on Spanish Language & Usage and, according to the related answers, it seems that in that language the word is envidia, but I'm not sure that in Italian is the same. Rather, I think that one of the candidate words is spazzatura.