Fresh matured papayas were harvested from papaya orchard of Farm Machinery and Post harvest Process Engineering Division, Bangladesh Agricultural Research Institute, Gazipur in February, 2013. Uniform size and same maturity papayas were selected for the experiment. These papayas were washed with fresh water to remove the dirt and latex from the fruit surface. Fruits were treated at different treating temperatures and exposure periods
(T1= Control (no treatment),
T2=Hot-water treatment at 48 °C for 25, minutes with 4% CaCl2 solution,
T3=48 °C for 30 with with 4% CaCl2 solution,
T4=48 °C for 35 minutes with 4% CaCl2 solution,
T5=48 °C for 40 minutes with 4% CaCl2 solution,
T6= 50 °C for 25 minutes with 4% CaCl2 solution,
T7= 50 °C for 30 minutes with 4% CaCl2 solution,
T8= 50 °C for 35 minutes with 4% CaCl2 solution,
T9= 50 °C for 40 minutes with 4% CaCl2 solution,
T10= 52 °C for 25, minutes with 4% CaCl2 solution,
T11= 52 °C for 30 minutes with 4% CaCl2 solution,
T12= 52 °C for 35 minutes with 4% CaCl2 solution,
T13= 52 °C for 40 minutes with 4% CaCl2 solution,
T14 = 54 °C for 5, minutes with 4% CaCl2 solution,
T15 = 54 °C for 10 minutes with 4% CaCl2 solution,
T16 = 54 °C for 15 minutes with 4% CaCl2 solution,
T17 = 54 °C for 20 minutes with 4% CaCl2 solution,
T18= 43°C for 40 minutes and later immediately immerse in 48°C for 20 minutes,
T19= 50 °C for 40 minutes and
T20= 48 °C for 20 minutes followed by cooling in running water for 20 min.
Fresh green matured papayas (2-5% yellow on the peel of fruits) and uniform size were harvested from papaya orchard of Papay Badsha, Dashuria, Ishurdi, Pabna in 2014 to conduct the experiment. The second year, papaya were treated at different temperature and exposure time without chemical mixture. These papayas were washed with fresh water to remove the dirt and latex from the fruit surface. Five papayas were selected for each replication. Each treatment was repeated three times. Weight loss, shelf-life, decay at weight basis, surface and pulp colour of papaya fruits were recorded. Weight of each replication (5 fruits) was recorded at different storage period (at harvest, 24 48, 72, 96 and 120 h after harvesting). The percentage of loss in weight was calculated on the basis of the initial weight. Shelf life (days) of papaya fruit of each treatment was recorded during the period of storage. It was calculated from the date of harvesting to last edible stage. Data on incidence and severity of different post harvest diseases of papaya were recorded when disease symptoms developed on the surface of ripened fruits. Data were statistically analyzed using SPSS 17 software by analysis of variance and significant differences among the treatments were determined using One–Way ANOVA at P≤0.05.