Proteome changes in Garnacha Tintorera red grapes during post-harvest drying

•It was found an increase in the number of protein bands after post-harvest drying.•During grape raisining there was a protein over-expression (33%) in response to stress.•Proteins involved in transcription and synthesis of other proteins decreased by 16%.•Proteins involved in metabolism were reduced in a 16% with drying.•A total of 24 proteins were identified by MALDI-TOF/TOF-MS.

Fruit raisining is accompanied by changes in composition due to the joint action of water loss and modifying enzymes. Cell walls in grape berries form a barrier against diffusion of aromatic and polyphenolic compounds that influence wine quality. In this work, fresh and post-harvest dried grape samples of Vitis vinifera L. Garnacha Tintorera variety were compared in terms of proteome. The main change observed during raisining was over-expression from 14 to 47% of proteins involved in pathogen- and stress-resistance mechanisms, whereas metabolism-related proteins or those involved in the transcription and synthesis of other proteins decreased, respectively, from 43 to 27% and from 29 to 13%. These changes are important in the functional qualities and stability of the sweet wines obtained, since affect interactions with other macromolecules or metabolites.