Respiration rate and mechanical properties of peach fruit during storage at three maturity stages

Knowledge of the physical, physiological and mechanical properties of fruits is important for its later harvest handling. The physical properties of peach fruit cv. Diamante harvested at physiological maturity stage were evaluated, obtaining the following values: sphericity (0.98), density (0.998 g cm^-3), bulk density (0.61 g cm^-3), porosity (0.38), and packing coefficient (0.70). The respiration rate and mechanical properties (compression load, strain and apparent elasticity modulus) of the peach fruit during storage at room temperature, as a function of its maturity stage (green, middle yellow and yellow) were also evaluated. Middle yellow fruits exhibited higher respiration rate than those corresponding to green and yellow ones. The peach fruit tissue showed anisotropic behavior, varying its mechanical properties with the orientation (tangential or radial) of the compressive load. The mechanical properties of peach exhibited a strong dependence on the degree of maturity at harvest and the rate of senescence progression.