Search Results
Abstract
Spraying trees of nectarine (Prunus persica (L.) Batsch) with succinic acid-2,2-dimethylhydrazide (daminozide) or 2-(2,4,5-trichlorophenoxy) propionic acid (fenoprop; 2,4,5-TP) at initiation of pit hardening induced earlier fruit ripening by enhancing the rates of growth and color development. The climacteric peak occurred earlier in fruit from either treatment than in the controls. Whereas fenoprop enhanced CO2 evolution more than daminozide, daminozide stimulated postharvest ethylene production more than fenoprop. Treatment with both regulators did not have an additive effect in advancing the harvest date, in spite of a significant increase in color development and a somewhat increased rate of fruit softening. There was, however, an additive effect in stimulation of ethylene evolution.
Abstract
SADH affected color enhancement of ‘Canino’ apricot (Prunus armeniaca L.) thereby increasing the percentage of fruit harvested during the first 2 harvests. The sprays at and after pit hardening had a greater effect on color than “after bloom” spray. Other parameters of ripening, however, were unaffected, or were even retarded, indicating the different effects of SADH on various species of stone fruits.
Abstract
A superficial browning disorder (scald) develops on the husk of ‘Wonderful’ pomegranate (Punica granatum L.) fruit during storage. The severity of this disorder could be diminished by delaying the harvest time and by reducing storage temperature, but these 2 measures were insufficiently effective for storage periods exceeding 6 weeks, and at temperatures of 6°C or lower, chilling injury also occurred. Scald incidence was correlated with the amount of o-dihydroxyphenols extractable from the husk, and was significantly controlled by measures that inhibited their oxidation by polyphenol oxidase. Such postharvest measures included dipping the fruit in boiling water for 2 minutes and in anti-oxidant solutions, in bisdithiocarbamate-containing maneb for 30 seconds, or storing the fruit in a low-O2 atmosphere. The most effective control of husk scald was obtained by storing late-harvested fruit in 2% O2 at 2°. However, this treatment resulted in accumulation of ethanol, which caused off-flavor development. When the fruit were transferred to air at 20°, ethanol and off-flavors dissipated.
The commercial storage life of the nonastringent Japanese `Fuyu' persimmon (Diospyros kaki L.), grown in Israel, was extended from 6 to 18 weeks at 0C by modified-atmosphere packaging (MAP) in a low-density polyethylene (LDPE) film. MAP retarded fruit softening and inhibited development of peel and flesh disorders, which limited the storage life of the naked fruit. The fruit maintained its external and internal quality within the MAP during a subsequent week at 20C in the 0.08-mm LDPE film. Fruit quality deteriorated more rapidly in a 0.06-mm package. The difference between fruit quality in the two packs is attributed to specific physiological effects of the different atmospheric equilibria established due to film thickness.
Abstract
Two orchard sprays with 800 ppm methyl l-(butylcarbamoyl)-2-benzimidazole-carbamate (benomyl) or three orchard sprays with 300 ppm 2-(4-thiazolyl) benzimidazole (thiabendazole or TBZ) achieved significant control of storage decay of ‘Spadona’ pears (Pyrus communis L.). Almost complete control of storage decay required postharvest dip-treatments of 1000 ppm benomyl or 500 ppm TBZ. Penicillium expansum and Botrytis cinerea (Pers. ex Fr.) were inhibited by these treatments but Alternaria tenuis (Nees ex Cda.) was unaffected and its incidence increased during storage, possibly due to control of the other organisms. These benzimidazole treatments tended to increase the incidence of internal breakdown of treated pears during prolonged regular cold storage.
Abstract
Various combinations of preharvest ethephon sprays were applied to ‘Granny Smith’ apples (Malus domestica Borkh). The fruit were harvested twice the first year with selective picking from the interior and exterior of the tree and three times the second year. Scald incidence was measured after storage at 0°C in air for 3 or 6 months plus 1 week at 20°. There was a correlation between scald after storage and fruit soluble solids concentration and firmness at harvest and with conjugated triene levels at harvest or after storage. Ethephon sprays reduced scald incidence between 20% to 75% depending on treatment and storage length.
Abstract
Control of woolly breakdown in ‘Elberta’ peaches was obtained by removal of the fruit to ambient room temperature (23–25°C) for 48 hours after 2 and 4 weeks' storage at 0°C. A 6 weeks' storage life was thus obtained. Warming the fruit after cold storage intervals shorter than 2 weeks was less effective after longer storage periods; the disorder was often enhanced by removal to room temperature.
A hypothesis to explain the development of woolly breakdown on the basis of these and previous data is discussed. It is suggested that further prolongation of storage could be obtained by repeated exposures to room temperature.
Abstract
The compositional changes occurring in the cell wall of maturing and ripening pear fruits (Pyrus communis L. cv. Spadona) were examined in relation to the activity of pectolytic enzymes and cellulase. Fruit softening was accompanied by a rise in water and EDTA-soluble pectic fractions, and in free galacturonic acid. The latter reached peak levels after 15 weeks of cold storage and thereafter declined. Simultaneously with the degradation of pectin there was a 4 to 5 fold increase in polygalacturonase activity, but pectin-methyl-esterase activity declined as it did throughout the harvest and storage seasons. Cellulase activity which was present also in immature fruit increased 2 to 3 fold as the fruit softened, but in the last stages of softening it decreased. Treatment of the firm fruit with partially purified preparations of cellulase and polygalacturonase both caused a dissolution of insoluble pectin material.
Abstract
Pomegranate (Punica granatum L. ‘Wonderful’) fruit reached horticultural maturity for commercial harvest when the soluble solids content (SSC) attained a fairly constant level of 15%. The level of titratable acidity (TA) varied from one location to another and from one year to the next but also generally remained stable at the same time that the SSC reached 15%. After harvest, there was no further change in either SSC or TA at 20°C, but redness of the juice continued to increase in intensity up to and after harvest. The respiration pattern of the mature fruit was of the nonclimacteric type, with only traces of ethylene evolved on occasion. Ethylene treatment of the fruit caused a rapid transient rise in CO2 evolution but no changes in SSC, TA, and fruit or juice color. A pseudo-climacteric pattern of respiration was found in very young immature fruit. The respiration rate of dehisced arils paralleled that of the intact fruit, but there was no response to exogenous ethylene treatment. Ethylene evidently stimulated the CO2 output only of the fruit rind.
Abstract
Controlled-atmosphere (CA) storage of astringent persimmon fruits (Diospyros kaki L.f. cv. Triumph) at −1° or 0°C enabled removal of astringency if CO2 content of storage atmosphere was 12% or more and O2 content was 3 to 5%. These gas combinations caused severe pulp injury and gave an alcoholic flavor to the fruit. At 3 to 9% CO2, astringency was reduced but not entirely removed and subsequent treatment of 12 hrs in 90% CO2 at 17°C was necessary to make the fruit edible. Storage life at −1°C was prolonged in 3% CO2 and 3 to 5% O2 due to less fruit softening and pulp discoloration. Higher CO2 concentration in the storage atmosphere accelerated softening, increased pulp injuries, and elevated respiration rates during shelf-life. Post-storage treatment in 90% CO2 at 17°C to remove astringency, slowed down the rate of fruit softening but accelerated the respiration rate, especially of CA-stored fruit.