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  • Author or Editor: Jean-Pierre Émond x
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‘Opus’ and ‘Leon’ snap beans were harvested, hydrocooled, held for 2 to 7 days at five temperatures and evaluated for quality attributes. The objectives of this work were to obtain quality curves at chilling and non-chilling temperatures, identify for each temperature which quality attributes limit snap beans marketability, and determine the remaining compositional value at the point the snap beans had reached the minimum acceptable quality for sale. Results from this study showed that temperature had a significant effect on the shelf life and overall quality of snap bean. Snap beans stored at temperatures higher than 10 °C were less green, softer and more shriveled, had higher weight loss, and lower acidity, soluble solids, ascorbic acid, and chlorophylls contents than those stored at lower temperatures. When stored at 1, 5, and 10 °C, ‘Leon’ snap beans developed chilling injury (CI), whereas no visual symptoms were noticeable in ‘Opus’ snap beans. Although CI might have indirectly affected the quality of ‘Leon’ snap beans, it was not considered a sensory quality-limiting factor. Overall, weight loss was the first non-sensory quality attribute to reach the limit of acceptability, whereas firmness was the first sensory quality attribute, followed by color, to reach the limit of acceptability and therefore limited the shelf life of ‘Opus’ and ‘Leon’ snap beans cultivars. As a result of excessive water loss and accelerated softening, shelf life of both snap bean cultivars was relatively short, ranging from 1 to 3.5 days, depending on the temperature and cultivar. Furthermore, the compositional value was considerably reduced at the point of poor sensory quality. The high weight loss obtained for beans stored at all temperatures suggests that the use of a film wrap may help create a high relative humidity and therefore reduce water loss, maintain better overall quality, and extend the shelf life of snap beans. Overall, maximum shelf life and best quality were obtained when ‘Opus’ and ‘Leon’ snap beans were stored at 10 °C.

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Abstract

The effect of controlled atmospheres on the regulation of ethylene biosynthesis during the senescence of broccoli flower buds (Brassica oleracea, L. Italica group cv. Green Valiant) was assessed. The broccoli buds wee stored in the dark at 25C under a continuous stream of nitrogen containing the following percentages of CO2-O2 : 0-20 (air), 0-2.5, 6-20, and 10-20. Generally, respiration, ethylene production, and ethylene-forming enzyme (EFE) activity followed a climacteric like pattern in all atmospheres. The ACC content changed little during the “climacteric”, but increased dramatically during the “post-climacteric” period, when ethylene production and EFE activity decreased. Under high CO2, respiration was reduced, but ethylene production and EFE activity were temporarily stimulated early during treatment. Under low O2, respiration, ethylene production, EFE activity, and ACC content were reduced, and the “climacteric” and chlorophyll losses were delayed to a greater extent than under high CO2. Whatever the treatment, ACC level was not the limiting factor in ethylene biosynthesis in broccoli; the reduction in ethylene production during senescence resulted from the degradation of the system that converts ACC to ethylene. Chemical name used: 1-aminocyclopropane-1-carboxylic acid (ACC).

Open Access

Commercial shipments of strawberries (Fragaria ×ananassa) were evaluated from the harvest point to the distribution center (DC). Simulated retail conditions were afterward imposed on the fruit. Commercially harvested ‘San Juan’ strawberries in California were instrumented in the field for temperature and relative humidity (RH) monitoring during handling and distribution. At the cooling facility, five different treatments were imposed on five pallets of strawberries: prompt precooling to a final temperature of 1.7 or 10.0 °C, 4-hour delayed precooling to a final temperature of 1.7 or 10.0 °C, and no precooling. Immediately before being loaded into the trailer, all pallets were wrapped in a modified atmosphere (MA) pallet shrouds. Upon arrival at the DC in Florida, fruit from the same five pallets were exposed to three simulated retail temperatures (0, 6, and 21 °C) for 3 days. Results from this study showed that the refrigerated trailer was unable to maintain the temperature of any of the pallets during transport. In addition, upon arrival at the DC in Florida, strawberries from the partial precooling (cooled to 10.0 °C), 4-hour delayed precooling, and no precooling treatments had higher water loss and lower visual quality compared with fruit that were immediately precooled to a final temperature of 1.7 °C. On the basis of the quality control standards of the cooling facility in California, most of the fruit from the no precooling treatment were considered unacceptable for shipment 1 day after harvest. During simulated retail display, quality of the fruit held at 21 °C was inferior to that of fruit maintained at 0 or 6 °C, particularly that of fruit from the partial and delayed precooling treatments. Strawberries from the prompt precooling to a final temperature of 1.7 °C treatment had acceptable visual quality after simulated retail display for 3 days at 0 °C, whereas visual quality of the fruit from the delayed or partial precooling treatments ranged from slightly poor to poor after the same period of time. The presence of bruises due to mechanical damage shortened the shelf life of the fruit because of accelerated development of decay. Overall, results obtained from this study highlight the importance of prompt precooling and the use of optimum storage temperature (i.e., 0 °C) throughout the distribution chain and during retail display.

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