Search Results
Abstract
Rates of ethylene production, respiration, and yellowing of broccoli (Brassica oleracea L. Italica group) at 20°C were reduced by an aminoethoxy analog of rhizobitoxine (AAR) [L-2-arnino-4-(2-arnino-ethoxy)-trans-3-butenoic acid] and by sodium benzoate (SB). Loss of chlorophyll and ethylene production were retarded by concn of 5 × 10-3M of AAR; at concn of 10-3M or 5 × 10-4M, the retardation was less pronounced. Yellowing and ethylene production were markedly reduced by SB at concentrations of 0.01M, 0.05M, or 0.1M. However, the latter two concentrations caused chemical injury and off-odor which resulted in unsalable quality. The data suggest that senescence of broccoli is related to ethylene production and that senescence can be retarded by inhibiting ethylene production.
Abstract
Exposure of sweet peppers (Capsicum annuum L.) to 30% CO2 for 6 days at 13°C immediately after harvest retarded wall softening and ripening in air at 13° but caused the subsequent development of severe calyx injury and decay at 20°. Slight to moderate calyx injury was induced by a 6-day exposure to 20% CO2. Severity of the injury was greater when the CO2 was used with 3% O2 as compared to 21% O2. Injury was not induced by a 6-day treatment with 10% CO2. When stored at 13°, quality of peppers with this treatment was superior after 10 days, but inferior after 20 days to that of peppers kept continuously in an atmosphere of 5% CO2 and 3% O2. Benefits obtained from the 3-day elevated CO2 treatment (10 to 30%) were nullified after 10 days’ storage at 13°. Ethylene production was greatly inhibited in high CO2 atmospheres but rose immediately after transfer to air. Red color development, chlorophyll degradation, and ascorbic acid accumulation were retarded only in the presence of high CO2.
Abstract
Pollen tube growth in styles of ‘d’Anjou’ pear (Pyrus communis L.) is largely dependent on prevailing temp. At 21°C the process was completed within 24 hr, while at 15.5° and 10° growth was completed by 72 and 120 hr respectively. The initial fruit development 14 days following pollination was greatly influenced by day temp (ranging from 13° to 23.4°) during an thesis.
Postharvest applications of polyamines reduced chilling injury of McIntosh apples and zucchini squash. McIntosh apples developed brown core, a symptom of chilling injury, after 5 months of storage at 0°C. However, this disorder was absent in fruit infiltrated with putrescine, spermidine, or spermine. Polyamine treatments also reduced softening of fruit tissue. Pressure infiltration of zucchini squash with spermine immediately after harvest reduced the severity of surface pitting during subsequent storage at 2.5°C. The elevation of spermidine and spermine levels and the augmentation of S-denosyl-methionine decarboxylase activity in squash by temperature preconditioning was also correlated with increased resistance of the squash to chilling injury.
Abstract
Friction discoloration of ‘d'Anjou’ pears (Pyrus communis L.) was found to be associated with total phenol and chlorogenic acid content. Concentrations of these substances in the skin decreased during fruit development but increased during storage. Tendency for friction discoloration also increased with storage duration. Treatments with ascorbic acid and sodium bisulfite reduced the susceptibility of skin to friction discoloration.
Abstract
Fruit of ‘Spartan’ apple (Malus domestica Borkh.) trees treated in April with paclobutrazol maintained greater firmness and had less internal breakdown than control fruit after 7 months in storage at 0°C. However, ACC level, ethylene production, respiration, soluble solids, sorbitol, fructose, glucose, sucrose, and malic acid content of the fruit after 0° storage and during ripening at 20° were not affected. Chemical names used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H- 1,2,4-triazole-1-ethanol (paclobutrazol); 1-aminocyclopropane-1-carboxylic acid (ACC).
Abstract
High chlorogenic acid level was associated with ‘d’Anjou' pear tissues affected with cork spot; tissues adjacent to the cork spot had next highest level. In fruit without cork spot symptoms, tissues on the sunlight exposed side had more chlorogenic acid than shaded tissue. Affected fruit had higher and accelerated rates of ethylene production and respiration than normal fruit.
Abstract
Quality and ripening capacity of ‘d’Anjou’ pears (Pyrus communis L.) after long-term storage were influenced by the daily-hourly average (DHA) temperatures during 6-week prior to harvest. Fruits of 17.2° and 13.9°C DHA temperatures ripened with high acid and sugar contents while samples of 20.0° and 11.7°C DHA temperature treatments failed to ripen properly and had lower quality. Failure to ripen after prolonged storage was associated with high protein nitrogen levels in the fruits. Samples of lower DHA temperature were more susceptible to friction discoloration, while fruits of higher DHA temperature had a higher percentage of superficial scald. Temperatures during this period did not appear to affect harvest maturity, size or soluble pectin content of the fruit.
Abstract
Small ‘d’Anjou’ pears (Pyrus communis L.) tend to be more susceptible to friction discoloration than the large fruits. Susceptibility to friction discoloration decreased with maturity but increased with duration of storage. Phenolic substances which are associated with friction discoloration and which serve as the substrate for polyphenoloxidase also declined with maturity and accumulated in storage. However, polyphenoloxidase activities increased with maturity and decreased during storage. The accumulation of phenolic compounds may be a result of the low polyphenoloxidase activities in storage.
Abstract
Treatment with 2-mercaptobenzothiazole (MBT) inhibited the friction discoloration of fruit of ‘d’Anjou’ pear (Pyrus communis L.). The inhibition was apparently due to inactivation of the pear polyphenoloxidase.