Relation of postharvest decay fungi to the deterioration of dried French prunes
Sholberg, Peter Leonard.
Ph.D., University of California, Davis, 1981, 58 pages.
1981
บทคัดย่อ
Deterioration of dried French prunes expressed by soft, sticky macerated areas on the fruit and sometimes slippage of the skin was studied. The greatest amount of deteriorated fruit after drying was obtained by inoculation of fresh fruit with Rhizopus arrhizus and R. stolonifer; some deterioration also occurred with other fungi such as Aspergillus japonicus, Penicillium expansum, Mucor circinelloides, Cladosporium herbarum and Monilinia spp. Other common fungi on dried prunes, such as the Aspergillus glaucus group, are not likely a part of the deterioration complex unless the prunes are improperly dried and held for extended periods. Rhizopus spp. are the fungi most likely to develop on fresh prunes held for 24 hr or less after harvest and the most likely to be related to deterioration of dried prunes. The following supporting evidence was provided: (1) Rhizopus spp. were always observed before drying when significant amounts of dried fruit were deteriorated, (2) fresh prunes inoculated
with Rhizopus spp. and incubated for 24 hr or more suffered severe deterioration, (3) sulfur dioxide fumigation to kill Rhizopus spp. on inoculated but undecayed fresh fruit prevented deterioration, and (4) naturally-deteriorated dried fruit obtained during commercial sorting and Rhizopus-inoculated fresh fruit that was dried contained polygalacturonase enzyme typical of that produced by Rhizopus spp. during decay of fresh fruit. Reduction in postharvest Rhizopus infection and decay development was obtained by: (1) dehydration within 24 hr after harvest, (2) holding the fresh fruit in cold storage and (3) treatment with certain chemicals such as potassium sorbate or sulfur dioxide.