Rheological and technological properties of two cider apple cultivars

Two cider apple cultivars (Avrolles and Douce Coetligné) were compared for their technological and rheological properties and the evolution of these properties during storage after harvest (15 or 30 days). Avrolles was characterized by high and stable juice yields whereas Douce Coetligné had a lower juice yield at harvest which further decreased during storage. The aim was to identify measures of fruit texture which might be related to the fruits behaviour during pressing. Force–displacement curves were computed during penetrometric and compressive tests performed on a TAXT2 texturometer on 20 fruits sampled at three dates. Two main rheological factors have been pointed out. First, under strain, Avrolles showed important plastic irreversible deformations with important breakdowns of cells layers whereas visco-elastic mechanisms appeared more important for Douce Coetligné. Secondly, for this last cultivar, during storagethe skin seemed to act increasingly as a protection against initiation and propagation of cells fractures inside the inner tissues.