Search Results
Abstract
Five cultivars of apples (Malus domestica Borkh.) each with 2 different harvest dates were stored in continuous flow controlled atmosphere (CA) at 3% O2 and 3% CO2 at 0°C or 3.3° for 3 to 7 months. Ethylene in the CA was maintained at 3 levels: low (mostly below 1 ppm, maximum 3.8 ppm), 10 ppm and 500 ppm. In comparison with low ethylene, 10 ppm and 500 ppm ethylene in CA did not significantly affect the soluble solids, titratable acids, firmness and sensory evaluated ripeness of ‘Delicious’, ‘Golden Delicious’, ‘Indared’ and ‘Cortland’ apples harvested on either date and of ‘McIntosh’ apples harvested after the onset of climacteric. However, ‘McIntosh’ harvested before the onset of climacteric retained higher acids, firmer texture and were sensory evaluated as less ripe when kept in CA with low ethylene than that with 10 or 500 ppm ethylene. ‘Delicious’ apples stored for 7 months in CA with 10 or 500 ppm ethylene developed severe scald but those in CA with low ethylene did not.
Abstract
High temperature (40°C) for 2 and 4 days lowered the acidity of 4 cultivars of apples (Malus domestica Borkh.). The preheated fruit was firmer than the control during 2 to 4 weeks of holding at 21°. The treatment also accelerated the loss of chlorophyll from the fruit skin. The soluble solid content of the fruit was not affected. Apples after the heat treatment had a normal respiratory climacteric and normal ethylene production rates. Some feasibility of applying high temperature to improve apple quality seems to exist.
Abstract
‘McIntosh’ apples (Malus domestica Borkh.) were harvested on 3 different dates and stored in controlled atmosphere (CA) storage with less than 1, 10 or 500 ppm ethylene. After 5 and 8 months of storage the fruits which had been harvested 5 to 6 days before the onset of the climacteric were less ripe and had less breakdown than fruits harvested after the onset of the climacteric. The fruits harvested at the preclimacteric stage had either comparable or slightly better eating quality but less red color than fruits harvested later. High levels of ethylene had slight but statistically significant negative effects on firmness and acidity of early harvested fruits judged by sensory evaluation after 5-month storage plus 7-day holding and by objective evaluation after 8-month storage plus 1- or 7-day holding at 21°C. An attempt was made to find a method to estimate the physiological age of preclimacteric apples. The minimum treatment time required for 10 ppm ethylene to trigger the onset of the climacteric at 21°C is judged to be promising.
The storage potential of ‘Empire’ apples [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] in controlled atmosphere storage has been studied. Fruit were treated with a range of partial pressures of CO2 (pCO2) from 0 to 5 kPa at storage temperatures of 0, 0.5, and 3 °C. The predominant storage disorders that developed were external CO2 injury, flesh browning (chilling injury), senescent breakdown (soft flesh browning), and core browning. All disorders except external CO2 injury increased with longer storage periods. The incidence of external CO2 injury was usually greater with higher storage temperature, whereas flesh browning was worst at lower storage temperatures and senescent breakdown was higher at warmer storage temperatures. The effect of storage temperature on core browning was not consistent. External CO2 injury, flesh browning, and core browning incidences were higher with increasing pCO2, especially above 2 kPa. Flesh firmness was lowest at warmer storage temperatures and in the absence of CO2. Orchard to orchard variation for all factors was high. Relationships of disorders with mineral concentrations were specific to disorder and storage conditions. The results suggest that ‘Empire’ should be stored at 1 to 2 °C, reflecting a compromise between risk of flesh browning at 0 °C and risk of senescent breakdown and unacceptably soft fruit at 3 °C and that pCO2 should be maintained below 2 kPa and closer to 1 kPa.
Abstract
‘McIntosh’ apples (Malus domestica Bork.) sprayed with 1000 or 2000 mg−1 liter−1 daminozide were stored in simulated low-ethylene controlled atmosphere (CA) storage for 7.5 and 9.5 months in 3 consecutive years. The simulated CA was a flow-through system with 2.5–3% O2, 3–5% CO2, <1 μ1·liter−1 ethylene, 2.2° to 3.3°C, and 90–95% relative humidity. A maturity index based on the date of the onset of autocatalytic ethylene production (AEP) of apples not sprayed with daminozide was used. ‘McIntosh’ apples, which were harvested within 10 days after the onset of AEP, lost <10% of their original firmness, 27–29% of acidity, and 0% of soluble solids after 7.5 months of storage. The rates of ethylene production of these apples were very low in the first 4 months, gradually increased thereafter, but remained <0.5 μl·kg−1·hr−1 for at least 7 months. The low-ethylene CA effectively preserved the quality and inhibited the ethylene production of ‘McIntosh’ apples. Chemical name used: butanedioic acid mono(2,2-dimethylhydrazide) (daminozide).
Abstract
The firmness of 1,034 fruits of apple (Malus domestica Borkh cv. ‘McIntosh’) evaluated subjectively by 1,034 retail customers and objectively by an Effe-gi penetrometer were correlated (r = 0.402). Customers rated 76% of the apples with a pressure test value of 5.9 kg (13 lb.) as “crisp, neither too hard nor too soft.” As the pressure test value decreased linearly from 5.9 to 3.6 kg (13 to 8 lb.) the percentage of fruits rated as crisp decreased, but the percentage rated as too soft increased linearly. The proportion of fruits rated as too soft was 66% for those with a pressure test value of 3.6 kg (8 lbs.) and 92% for those with 3.2 kg (7 lbs.). Young people (20 to 35 years) showed a stronger preference than middle-aged people (36 to 59 years) for firm apples. Female consumers showed a stronger preference than male consumers for firm apples.
As part of a program to develop transgenic peach (Prunus persica L. Batsch) cultivars with resistance to Prunus necrotic ringspot virus (PNRSV), we are testing a system for measuring virus in peach shoot cultures. Micrografting in vitro is used for inoculation and slot-blot hybridization, with a digoxigenin (DIG)-labeled cRNA probe complementary to the 5′ open reading frame (ORF) of PNRSV RNA 3, for detection. In this study, we investigated whether infected shoots maintain virus infection over long periods of culture at 4 °C and if PNRSV-infected `Suncrest' shoot cultures can serve as graft bases to transmit virus equally well into cultivars Nemaguard, Springcrest, and Suncrest. The results of RNA hybridization analysis showed that virus was present in extracts of leaf samples from 2-year-old PNRSV-infected `Suncrest' shoots that had been subjected to varying lengths of incubation at 4 °C in the dark, suggesting that infected shoots can be maintained for repeated use. Rates of graft success were higher in heterografts between `Suncrest' bases and tips of `Springcrest' or `Nemaguard' than in autografts between `Suncrest' and `Suncrest', and there was equal efficacy of graft inoculation from `Suncrest' into these three cultivars.
Abstract
Daminozide-sprayed ‘McIntosh’ apples (Malus domestica Borkh.) were stored for 7.5 to 8 months in 19-liter jars with flow-through controlled atmosphere (CA) at 3.3°C. Various combinations of gases were tested in 2 years: 1%, 1.5%, 2%, 2.5%, and 3% O2; 0%, 3%, and 3→5% (3% for one month and then 5%) CO2; and <1 and 500 μl·liter−1 ethylene. High ethylene caused significant softening of apples in 3% O2 + 3% CO2 or 3% O2 + 3→5% CO2 (3 + 3 or 3 + 3→5), but its effect diminished by lowering O2 concentrations. In 1 + 3, the 2 concentrations of ethylene made only a slight difference in fruit firmness in one year and no difference in another year. In <1 μl·liter−1 ethylene, lowering O2 concentrations from 3% to 2% and 1% did not increase fruit firmness, but did reduce rates of ethylene production. A small percentage of apples developed skin injury in 1 + 3 and 1.5 + 3 in one year, and apples of one of 3 jars stored in 1 + 3 developed slight off-flavors in another year. A storage atmosphere of 2 + 3 and <1 μl·liter−1 ethylene, which kept apples firm without injury or off-flavor and with very low rates of ethylene production, may be ideal for low-ethylene CA storage of daminozide-sprayed ‘McIntosh’ apples. Chemical names: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide).
Abstract
‘McIntosh’ apples (Malus domestica Borkh.) sprayed with 1000 or 2000 mg·liter−1 daminozide in July 1982 were harvested in September and stored in a semicommercial sized, low-ethylene controlled atmosphere (CA) room at 2.2 to 3.3°C until May 1983. An ethylene scrubber containing 45 kg of potassium permanganate-alumina beads and a blower kept the ethylene concentration below 0.05 μl·liter−1 throughout the storage period. Fruit samples were taken out of storage periodically for quality and shelf life evaluations. Most of the apples taken out in Apr. 1983 were still preclimacteric. Apples stored in the low-ethylene CA until May lost only 3.5% of their original flesh firmness. Comparable apples lost 24.2% of firmness in a commercial CA storage without ethylene scrubbing. During a 6-day holding period in air at 20°, the rates of softening of apples from both low-ethylene and commercial CA storage were substantially faster than the rate of softening of freshly harvested apples. Chemical names used: butanediolic acid mono(2,2-dimethylhydrazide) (daminozide).