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R.J. Bender, J.K. Brecht, E.A. Baldwin, and T.M.M. Malundo

To determine the effects of fruit maturity, storage temperature, and controlled atmosphere (CA) on aroma volatiles, mature-green (MG) and tree-ripe (TR) `Tommy Atkins' mangoes (Mangifera indica L.) were stored for 21 days in air or in CA (5% O2 plus 10% or 25% CO2). The MG fruit were stored at 12 °C and the TR fruit at either 8 or 12 °C. Homogenized mesocarp tissue from fruit that had ripened for 2 days in air at 20 °C after the 21-day storage period was used for aroma volatile analysis. The TR mangoes produced much higher levels of all aroma volatiles except hexanal than did MG fruit. Both MG and TR mangoes stored in 25% CO2 tended to have lower terpene (especially p-cymene) and hexanal concentrations than did those stored in 10% CO2 and air-stored fruit. Acetaldehyde and ethanol levels tended to be higher in TR mangoes from 25% CO2 than in those from 10% CO2 or air storage, especially at 8 °C. Inhibition of volatile production by 25% CO2 was greater in MG than in TR mangoes, and at 8 °C compared to 12 °C for TR fruit. However, aroma volatile levels in TR mangoes from the 25% CO2 treatment were in all cases equal to or greater than those in MG fruit treatments. The results suggest that properly selected atmospheres, which prolong mango shelf life by slowing ripening processes, can allow TR mangoes to be stored or shipped without sacrificing their superior aroma quality.

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Robert A. Saftner, Judith A. Abbott, William S. Conway, Cynthia L. Barden, and Bryan T. Vinyard

Fruit quality, sensory characteristics, and volatiles produced by 'Gala' apples (Malus ×domestica Borkh.) were characterized following regular atmosphere (RA) storage without and with a prestorage heat treatment (38 °C for 4 days) or controlled atmosphere (CA) storage at 0 and 2 °C for 0 to 6 months plus 7-day shelf life at 20 °C. Static CA conditions were 0.7 kPa O2 plus 1.0 kPa CO2, 1.0 kPa O2 plus 1.0 kPa CO2, and 1.5 kPa O2 plus 2.5 kPa CO2. Most of the more abundant volatiles were esters; the rest were alcohols, an aldehyde, a ketone, and an aryl ether. Respiration and ethylene production rates, internal atmospheres of CO2 and ethylene, and volatile levels were reduced following CA storage compared with RA storage without and with a prestorage heat treatment. Magness-Taylor and compression firmness, titratable acidity, and sensory scores for firmness, sourness, apple-fruity flavor, and overall acceptability were higher for CA-than for RA-stored fruit. Soluble solids content and sensory scores for sweetness were similar among all treatments. Quality and sensory characteristics were generally similar in heated and nonheated RA-stored fruit, and between 0 and 2 °C in CA- and RA-stored fruit. While one CA regime had a higher CO2 concentration than the others tested, CA effects on quality and sensory characteristics were generally more pronounced at the lower O2 levels. Quality characteristics declined between 2 and 4 months storage. The results indicate that short-term CA storage can maintain instrumental and sensory quality of 'Gala' apples.

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N. Lallu, J. Burdon, D. Billing, D. Burmeister, C. Yearsley, S. Osman, M. Wang, A. Gunson, and H. Young

There are three main systems for the removal of carbon dioxide (CO2) from controlled atmosphere (CA) stores: activated carbon (AC) scrubber, hydrated lime scrubber, and nitrogen (N2) flushing. Each system is likely to have a different effect on the accumulation of volatiles other than CO2 in the store atmosphere, and these volatiles may influence the storage performance of the produce. `Hayward' kiwifruit (Actinidia deliciosa) were stored at 0 °C (32.0 °F) under 2% oxygen (O2) and 5% CO2 in CA rooms fitted with one of the three systems. In a fourth CA room, fruit were stored at 0 °C under air conditions. All four stores had their atmosphere scrubbed for ethylene. The store atmospheres and fruit firmness were monitored at intervals up to 27 or 14 weeks of storage in the 1999 or 2000 season, respectively. At the end of CA storage, and after an additional 4 weeks of air storage at 0 °C, fruit were evaluated for rots and physiological pitting. Linear discriminant analysis (LDA) showed the three CO2 removal systems altered the volatile profiles of the store atmospheres differently. CA storage delayed fruit softening markedly, and once returned to air, softening resumed at a rate equivalent to that of fruit of equivalent firmness that had not been CA stored. There was little effect of CO2 removal system on the fruit softening during storage. Although CA storage resulted in a higher incidence of rots, there was little difference among CO2 removal systems compared to the main effect between air and CA storage. Similarly, CA storage delayed the appearance of physiological pitting, although the incidence increased rapidly during an additional 4 weeks of storage in air, and was higher than for fruit stored throughout in air. Among the CO2 removal systems, N2 flushing resulted in fruit with the lowest incidence of physiological pitting. It is concluded that different CO2 removal systems alter room volatile profiles but may not consistently affect the quality of `Hayward' kiwifruit during CA storage.

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Elhadi M. Yahia, Dora Ortega, Pamela Moreno, and Alejandro Martinez

Previous work in our laboratory and also reported in this meeting has indicated that insecticidal controlled atmospheres at high temperatures (0.5% O2 + 50% CO2 at 44-55°C and 50% RH) are very effective in causing in vitro mortality of eggs and third instar larvas of Anastrepaha ludens and A. obliqua. This work is a follow up that evaluated the effect of such atmospheres on the in vivo mortality of third instar larvas artificially infested in mango. Atmospheres evaluated included 0% O2+ 50% CO2 at 35, 37, 39, 40, 42, 43, 44, 45, 46, 47, 48, and 49°C for 160 min. Treatments at 35-40°C caused 100% mortality of larvas of A. obliqua, but not of A. ludens. Temperatures of 42 to 49°C caused 100% mortality of larvas of both species. Statistical analysis to calculate the probit 9 will be discussed.

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Christopher B. Watkins and Jacqueline F. Nock

The effects of temperature during 1-MCP treatment, and the effects of delays of up to 8 d after harvest before treatment, have been investigated using `Cortland', `Delicious', `Jonagold', and `Empire' (normal and late harvest) apple [(Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] cultivars stored in air for 2 and 4 months and in controlled atmosphere (CA) storage for 4 and 8 months. Fruit were treated with 1 μL·L–1 1-MCP for 24 hours on the day of harvest (warm) or after 1, 2, 3, 4, 6, or 8 days at cold storage temperatures. CA storage was established by day 10. Little effect of temperature during treatment (warm fruit on the day of harvest compared with cold fruit after 24 hours of cooling) was detected. Major interactions among cultivars, handling protocols before 1-MCP treatment, storage type and length of storage were observed. Delays of up to 8 days before 1-MCP treatment either did not affect efficacy of treatment, or markedly reduced it, depending on cultivar, storage type and length of storage. The results indicate that, depending on cultivar, the importance of minimizing the treatment delay increases as storage periods increase.

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Elhadi M. Yahia, Dora Ortega, Alejandro Martinez, and Pamela Moreno

In this study, we report on the effect of insecticidal controlled atmospheres at high temperatures on the in vitro mortality of eggs and third instars larvas of A. ludens and A. obliqua. Atmosphere evaluated were air, 0% O2, 13% O2 + 20% CO2, and 0% O2 + 50% CO2 at 44°C for 160 min. Other treatments evaluated included 0% O2 + 50% CO2 at 48°C for 160 and 220 min and the same atmosphere at 40, 50, 51, 52, 54, and 55°C for 240 min and at 48°C and 55°C for 80, 160, and 240 min. Both species responded similarly to the treatments applied. Larvas were more sensitive than eggs in both species. A 100% mortality of larvas of the two species was obtained in 0% O2 + 50% CO2 at 48°C, but there were survivals in eggs of both species. Treatment with 0% O2 + 50% CO2 at 55°C for 240 min resulted in 100% mortality in eggs and larvas of both species. Less extreme conditions (temperature and duration of treatment) caused high but inconsistent mortality, probably due to variability in insect population. Statistical analysis for the calculation of probit 9 will be discussed.

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G. Hong and M.I. Cantwell

Minimal processing of green onions (Allium cepa × A. fistulosum) involves trimming and removing damaged leaves, cutting of roots, and removal of the compressed stem. If the stem tissue is completely removed with the roots, the white inner leaf bases may extend, or “telescope,” during storage. Storage at 0 °C greatly retards extension growth, but storage at 5 °C results in unacceptable extension rates. To maintain high quality and to extend the shelf life of intact and minimally processed green onions, the potential benefits of heat treatments and controlled atmosphere storage were evaluated. Atmospheres of 0.1% to 0.2% O2 or 0.1% to 0.2% O2 containing 7.5% to 9.0% CO2 at 5 °C were the CA conditions that best maintained visual appearance and prolonged shelf life to more than 2 weeks in both intact and cut onions. No CA treatment completely controlled “telescoping” at 5 °C. Several heat treatment combinations (52.5 and 55 °C water for 4 and 2 min, respectively) of the white inner leaf bases were effective in controlling “telescoping” of cut green onions stored at 5 °C. The effective heat treatments resulted in higher average respiration rates during 12 days, but did not affect the visual quality or shelf life of the cut green onions. Total soluble sugars decreased in intact or cut green onions, but concentrations were maintained in heat -treated onions. Thiosulfinate concentrations did not vary importantly during 14 days at 5 °C, except for a reduction in heat-treated onions not stored under CA.

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Yukari Murakami, Yoshihiko Ozaki, and Hidemi Izumi

storage, and active MAP. High CO 2 controlled atmosphere storage. Twelve enzyme-peeled slices weighing 400 to 500 g were placed into a 2-L plastic container containing 5 mL of distilled water in a plastic beaker to maintain a high relative humidity. Three

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Kathleen Delate, Andrea McKern, Robert Turnbull, James T.S. Walker, Richard Volz, Allan White, Vincent Bus, Dave Rogers, Lyn Cole, Natalie How, Sarah Guernsey, and Jason Johnston

quality, at harvest and after controlled atmosphere (CA) treatment, of New Zealand scab-resistant cultivars with potential for importation into the United States; 4) to determine the effect of a systems approach using pheromone technology on leafroller

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Jennifer DeEll and Behrouz Ehsani-Moghaddam

values using an ICA 61/CGS 610 CA Control System (International Controlled Atmosphere Ltd., Kent, U.K.), which was modified with flow controllers for the experimental chambers (Storage Control Systems Inc.). Fruit quality evaluations. Initial fruit