The quality of `Galia' melons (Cucumis melo pv. reticulates) stored in a controlled atmosphere (CA) of 10% CO2 plus 10% O2 with ethylene absorbent (EA) for 14 days at 6C and an additional 6 days at 20C was significantly better than that of control fruit or fruit stored in CA only. Fruit stored in CA plus EA were firmer and exhibited less decay than fruit from the other two treatments.
Yair Aharoni, Azica Copel, and Elazar Fallik
Yair Aharoni, Akiva Apelbaum, and Azika Copel
The influence of reduced atmospheric pressure on the green peach aphid, Myzus persicae, in lettuce (Lactuca sativa L.) heads was determined. Exposing lettuce heads to a pressure of 2.66 kPa for 52 hr resulted n 100% aphid mortality, whereas the lettuce marketing quality was not affected. In view of the marked requirement for aphid-free lettuce heads, commercial use of the nonchemical reduced pressure method is suggested.
Joseph K. Stewart and Yair Aharoni
Vacuum fumigation for 2 hours with 0.5, 1.0, or 1.5% ethyl formate (EF) killed 93–97% of the green peach aphids [Myzus persicae (Sulzer)] in film-wrapped, packed head lettuce (Lactuca sativa L.). EF at 0.5% did not injure the lettuce, but 1.0 or 1.5% EF injured 30 and 97% of the heads, respectively. Regardless of the EF dosage used, about 75% of the fumigant was sorbed by the lettuce within 1 hour. A 1-hour vacuum fumigation using 0.5% EF appears to be optimal to control the green peach aphid in film-wrapped, packed lettuce.
Werner J. Lipton and Yair Aharoni
Exposing ‘Honey Dew’ muskmelons (Cucumis melo L.) at 20°C to 1000 ppm ethylene for 24 hours before storage at 2.5° for 2½ weeks reduced the incidence of chilling injury (Cl) by at least 75% and virtually eliminated objectionable Cl. The treatment also permitted 83% of the melons to proceed from minimum horticultural maturity initially to at least an acceptable degree of ripeness during 2½ weeks at the low temperature followed by 2 to 4 days at 20°. Only 41% of the control melons reached a desirable degree of ripeness. Cl was virtually absent in melons held at 5°, whether or not they were treated with ethylene, but ethylene also accelerated ripening at 5°. Almost half of the gassed melons were at or beyond maximum ripeness for eating after 2 to 4 days at 20°, whether stored initially at 2.5 or 5°. ‘Honey Dew’ melons with any degree of solar yellowing were highly resistant to Cl. Decay was negligible in all lots after 2½ weeks at 2.5 or 5°, but objectionable degrees of decay affected twice as many ethylene-treated as control melons after 2 to 4 days at 20°. Overall, treatment with ethylene followed by storage at 2.5° yielded the highest proportion (40%) of good to excellent melons after they were ripened for 2 to 4 days at 20°.
Werner J. Lipton, Yair Aharoni, and Elizabeth Elliston
‘Honey Dew’ muskmelons (Cucumis melo L.) treated with ethylene (1000 ppm) ripened more rapidly than did untreated melons during a 24-hour treatment at 20°C and during a subsequent 15 to 19 days at 2.5°, a chilling temperature. During the exposure to ethylene, the respiration rate was substantially higher in treated than in control melons, but the rates differed little during subsequent storage in normal air at 2.5°. Ethylene production was lower in treated than in control melons during storage at 2.5°, even though ethylene evolution was stimulated by the initial ethylene treatment. The Hunter a/b ratio of the surface color decreased significantly during the 24-hour ethylene treatment, which indicates that ripening had progressed during the treatment.
Victor Rodov, Batia Horev, Yakov Vinokur, Azica Copel, Yair Aharoni, and Nehemia Aharoni
Modified-atmosphere (MA) packaging using bag-in-box Xtend® liners extended the postharvest life of nonnetted Charentais-type muskmelons (Cucumis melo L., Cantalupensis Group, cv. Luna) by delaying over-ripening: excessive softening, change of rind color, decreased soluble solids, and the development of postharvest pathogens. The most delayed fruit ripening was achieved by an atmosphere of 13-14 kPa CO2 and 7-10 kPa O2, even though ethylene concentrations were as much as 120 μL·L-1. Charentais fruit stored in this atmosphere at 6 to 7 °C maintained marketable quality for 12 days plus additional 3 days at 20 °C. In contrast, lifespan under commercial conditions in air did not exceed 3-5 days at 10 to 11 °C plus 3 days at 20 °C. The recommended MA was achieved by using the liners with low microperforation level (total perforation area 25 × 10-5 percent of the film surface), 8-9 fruit of total weight ≈5 kg per liner. MA packaging of Charentais melons makes possible their transportation from Israel to Europe by sea instead of air.
Bryan R. Anthony, D.J. Phillips, S. Badr, and Yair Aharoni
Moist air heat treatment at 52C for 15 min prevented decay in individually plastic-wrapped or naked nectarine [Prunus persica (L.) Batsch var. nectarina (Ait.) Maxim.] fruit puncture-inoculated with Monilinia fructicola (Wint.) Honey. Heat treatment for 5 or 10 min slowed decay development, but did not prevent it. In treatments where decay occurred, the wrap increased decay. Heat treatment tests at 52C for 15, 30, 45 min slowed softening and ethylene production of fruit. Wrapping alone reduced ethylene production 75% and respiration 12%, but did not significantly influence softening. The wrap reduced or eliminated undesirable skin browning associated with heat treatments.
Yair Aharoni, Joseph K. Stewart, Dan G. Guadagni, and Thomas R. Mon
Vacuum fumigation at 560 mm Hg for 3 hr with acetaldehyde (Aa) at 1.75% in 70% CO2 killed 100% of western flower thrips Frankliniella occidentalis (Pergande), on strawberries (Fragaria × ananassa Duch.). However, the Aa treated berries were generally detectable in taste tests during the ensuing 3 days. Some panelists could distinguish the different taste of the treated strawberries from control samples even after 7 days. Ethyl formate (EF) in concentrations as low as 0.5% for 1 hr at 30 mm Hg pressure killed 100% of the thrips. EF fumigation affected neither taste nor odor of the berries during a subsequent 9 days of storage at 1°C. Fumigation with Aa in 70% CO2 decreased berry decay by 69%, but EF had no effect on decay. The concentration of EF, which was determined on the day of treatment and during the ensuing 4 days, was 0.2 ppm or lower in the treated strawberries. This concentration did not differ significantly from that in the controls and is at least 100 times less than the odor threshold concentration for EF.
Joseph K. Stewart, Yair Aharoni, Preston L. Hartsell, and David K. Young
Acetaldehyde (Aa), a volatile produced in small quantities by plants, is a potential fumigant for killing the green peach aphid, Myzus periscae (Sulzer), on harvested head lettuce, (Lactuca sativa L. var. capitata). Concentrations of 3.0 to 6.0% Aa killed 100% of the green peach aphids on harvested head lettuce, but induced dark-green, water-soaked, necrotic areas on the outer leaves of the heads and occasionally caused a type of injury, similar to russet spotting, which we call tan flecking. Concentrations of 1.5 to 2.0% Aa, which killed all of the aphids, did not injure the lettuce.