Effects Of Ultrasonic Wave Combine CaCl₂Treatment On Physiology And Quality Of Postharvest Peach And Persimmon

Persimmon (Diospyros kaki) and peach (Prunus persica) were treated by ultrasound wave (50 kHz,200 W, 3 min), CaCl2(3%)immersion, or their combinations, then the fruits were stored at 0±1℃and 10±1℃or 0±1℃, respectively. The parameters of quality and physiology in the fruits were measured for the evaluating effects of the treatments.The results in persimmons showed that:the treatments of ultrasound wave, CaCl2 and their combinations improved Hunter L on the surface of the fruits,especially the combinations. There were no obvious differences on Hunter a and Hunter b of the fruits among the treatments. The contents of soluble solids in treated persimmons were higher than those in untreated ones,which were benefit for the edible quality of persimmon. The calcium content in the fruit of combinations treatment were higher than those in the fruits of CaCl2 and control, which indicated that ultrasound wave promoted the absorbance of calcium in persimmon. The combinations treatment restrained lipoxygenase (LOX) activity, synthesize of ethylene and respiration,decreased superoxide anion radical (·O2-) production rate and hydrogen peroxide (H2O2) content, increased activities of superoxide dismutase(SOD), catalase(CAT)in the fruits during storage, which delayed senesces of persimmon.The results in peaches showed:at 10±1℃or 0±1℃, there were no obvious differences on skin colour or soluble solids content among the treated fruits and control, but the decreases of flesh firmness and titritable acid content were slowed down, and the rotten and brown of peaches were alleviated. The combinations treatment restrained LOX activity, synthesize of ethylene and respiration in peaches during storage. At 0±1℃, all the treatments restrained the increase of electrolyte permeability in flesh, which protected cell membrane integrality. The combinations treatment decreased the accumulation of malondialdehyde (MDA) in fruits maintained the cell figure and configuration. The combinations treatment increased the activities of superoxide dismutase(SOD)and catalase(CAT)of peaches in various extents, whose efficiency was superior to those in the fruits treated with ultrasound wave or calcium. The combinations treatment decreased the peroxidase(POD)activities, the production rate of superoxide anion radical (·O2-) and the hydrogen peroxide (H2O2) contents at different periods of storage at 2 temperatures. There were no obvious differences of the parameters above among the fruits during the shelf life.