The purpose of the present study was to investigate the role of ethylene action, via use of the ethylene antagonist 1-methylcyclopropene (1-MCP), on the senescence and quality of fresh-cut ripe papaya (Carica papaya L. `Sunrise Solo') fruit. Ripe papaya fruit were treated with 2.5 μL·L-1 1-MCP and immediately processed into fresh-cut slices or left intact. At 2-day intervals over 10 days at 5 °C, continuously stored slices were monitored for ethylene production, firmness, electrolyte leakage, color, sensory changes, and pathogen incidence. Slices freshly prepared from intact fruit stored under identical conditions were measured similarly. Ethylene production did not differ significantly between the treatments, although production rates were slightly but consistently higher in slices from intact control compared with intact 1-MCP-treated fruit. Mesocarp firmness of continuously stored slices and slices from fruit stored intact was significantly retained by 1-MCP. Firmness of continuously stored slices from 1-MCP-treated fruit declined 50% compared with 75% for control slices. Firmness of fresh-cut slices prepared from intact control and 1-MCP-treated fruit at each sampling interval declined 26% and 15%, respectively. Electrolyte leakage remained low and changed little in slices freshly prepared from fruit stored intact. Leakage from continuously stored papaya slices increased after 4 days, and after 6 days controls increased significantly compared with stored slices derived from papaya fruit initially treated with the ethylene antagonist. The flesh color of continuously stored slices or slices prepared from fruit stored intact was influenced by 1-MCP only during the later periods of storage. Microbial counts in stored slices or slices prepared at each sampling were generally unaffected by 1-MCP. Informal sensory analysis indicated that the edible shelf life was 6 days in stored slices from 1-MCP-treated fruit compared with 2 to 3 days for stored slices from control fruit.
Muharrem Ergun, Donald J. Huber, Jiwon Jeong, and Jerry A. Bartz
Sarah M. Smith, John W. Scott, and Jerry A. Bartz
When tomato (Lycopersicon esculentum Mill.) fruit come in contact with water at the packing house dump tanks, they can infiltrate water through the stem scar. If the water is infested with Erwinia carotovora, the fruit can infiltrate the bacteria, which will later develop into bacterial soft rot. To determine the inheritance of low water infiltration and thus tolerance to soft rot, a complete diallel was produced using six parents that infiltrate different amounts of water. The parents and hybrids were grown in a completely randomized block design with three blocks and 10 plants per block. The amount of water infiltrated by the fruit was measured by the change in weight after the fruit were immersed in water in a pressure cooker for 2 min. Both general combining ability (GCA) and specific combining ability (SCA) were significant, with GCA having a higher significance than SCA. There appeared to be a cytoplasmic effect on water uptake, where less water was taken up when the low-uptake parent was used as a female. When orthogonal contrasts were performed on reciprocal hybrids from parents that were significantly different, 33% of them were significantly different.