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  • Author or Editor: R. B. H. Wills x
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Broccoli (Brassica oleracea), green bean (Phaseolus vulgaris), and bok choy (Brassica chinensis) were fumigated with nitric oxide (NO) gas in air or in nitrogen for 2 hours at 20

°C (68.0 °F), then stored at 20 °C in humidified air containing 0.1 μL.L-1 (ppm) ethylene. The postharvest life of all vegetables was extended by NO although the concentration of NO required and the magnitude of the extension varied between produce ranging from 14% for green bean to more than 50% for broccoli. NO uptake by produce from air was not significantly different than from nitrogen at the lower effective NO concentrations, but NO uptake was less from air at the highest concentration used for broccoli. Application of NO in an air atmosphere is considered a feasible, more convenient treatment regime for horticultural produce than use of a nitrogen atmosphere.

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A systematic study was conducted on the ability of potassium permanganate absorbent to remove low levels of ethylene from the atmosphere. Absorption of potassium permanganate onto alumina beads by dipping in a saturated solution was maximal at 2 g/100 g after 2 hours at 20 °C and 4 g/100 g after 1 hour at 65 °C. Commercial alumina-based absorbents were found to contain potassium permanganate at 2.7 to 6.0 g/100 g suggesting many are prepared at elevated temperature. Trials in a closed system at 20 °C and 60% to 70% RH with alumina beads containing potassium permanganate at 4 g/100 g showed a logarithmic decrease in ethylene concentration with 90% of the ethylene removed after 2.5 to 3.0 hours. Relative humidity (RH) had a marked inverse effect on ethylene absorption with reactivity at 100% RH calculated to be 15% of that at 0% RH. Performance of potassium permanganate where ethylene was continually generated by a continuous flow of ethylene at 14 μL·h-1 through the container showed a steady state was attained within 1 hour and maintained for 24 hours. Ethylene removal increased linearly with bead weight and ranged from 30% with 1 g to 90% with 50 g. Examination over 20 days showed a continuing decrease in rate of ethylene removal which after 14 days had declined to 10% of incoming ethylene although 44% of the original level of potassium permanganate still remained in the beads. Calculations based on known endogenous ethylene production rates suggest that at 20 °C and 90% RH, use of a potassium permanganate-alumina absorbent would be beneficial with produce having a low level of ethylene generation. Suitability for larger packages of produce generating higher ethylene levels is questionable as >1 kg of absorbent may be required.

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Abstract

The endogenous levels of calcium in the cell walls of pericarp tissue of tomato (Lyco-persicon esculentum Mill.) and the soluble and bound calcium content of this tissue were examined during fruit growth and maturation. Cell wall calcium level increased during fruit development to the fully grown, immature stage, but dropped just prior to the onset of ripening. The changes in soluble and bound calcium during ontogeny indicated that calcium was solublized during the early stages of ripening.

Open Access

Abstract

A method to measure the severity of chilling injury (Cl) in stored avocados (Persea americana Mill.) is described that gives better results than visual appraisal. Colored metabolites are extracted from chilled mesocarp and measured in a colorimeter.

Open Access

Abstract

Fruit of avocado (Persea americana Mill.) were stored for up to 6 weeks in air or ethylene-enriched air at low temperatures. In one experiment, opposite ends of intact fruit were exposed individually to ethylene-enriched air. The severity of chilling injury of ripened fruit was significantly greater in fruit or fruit ends exposed to low ethylene concentrations.

Open Access

Abstract

The use of plastics in horticulture is increasing for such purposes as temporary protection of plants in the field, mulching of crops, and greenhouse construction. During studies using polyethylene covers on banana bunches, we found that ethylene accumulated to physiologically high levels within the covers. We examined this further by preparing sealed bags from films of clear and pigmented polyethylene and also from clear polypropylene, polyvinyl chloride, and nylon.

Open Access

Abstract

The application of fat soluble antioxidants to ‘Jonathan’ apples (Malu.s domestics Borkh.) after harvest reduced the incidence of soft scald which developed in the fruit during cool storage, increased the amount of unsaturated fatty acidss in the surface lipids, and reduced the level of hexanol in the fruit. Diphenylamine, butylated hydroxvanisole and ethoxvquin were the most effective of the compounds tested.

Open Access

Abstract

Respiration at 20°C of carrot roots (Daucus carota L.), potato tubers (Solanum tuberosum L.) and zucchini fruits (Cucurbita pepo L.) was reduced following exposure to either high levels of CO2 or low levels of O2 for a few days at 20°C. The reduced respiration rates were maintained for at least 2 weeks after treatment while the produce was ventilated with air.

Open Access

Abstract

For the control of soft scald of ‘Jonathan’ apples (Malus domestica Borkh.), a dip containing both diphenylamine and a vegetable oil was generally more effective and was considered to be more desirable than the use of either compound alone.

Open Access

Abstract

CaCl2 dips reduced the incidence of storage breakdown in ‘Jonathan’, ‘Cox’s Orange Pippin’ and ‘Twenty Ounce’ apples. The use of CaCl2, benomyl and diphenylamine in a single dip further enhanced the effect of CaCl2 The uptake of water into fruit was increased by reducing the dip temperature from 20° to 5°C or by increasing the dip time from 0.5 to 30 minutes but CaCl2 dipping was no more effective in controlling breakdown at 5° than at 20°.

Open Access