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  • Author or Editor: Joshua D. Klein x
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Susceptibility of apples (Malus domestica Borkh. ‘Gala’ and ‘Granny Smith’) to impact damage increased from early to late harvest time and decreased during storage at 1°C. Impact damage was quantified as bruise depth, diameter, volume, or weight. Bruise weight calculated as a percentage of fruit weight was the least variable measurement of bruising that was also proportional to height to impact of the fruit. Although a range of 22 New Zealand-grown apple cultivars differed in susceptibility to bruising, the variation was not correlated with fruit density, fruit firmness, or polyphenol content and polyphenoloxidase (PPO) activity in epidermal and cortical fruit tissues.

Open Access
Author:

Abstract

In the article “Relationship of Harvest Date, Storage Conditions, and Fruit Characteristics to Bruise Susceptibility of Apple”, by Joshua D. Klein (J. Amer. Soc. Hort. Sci. 112:113–118, January 1987), the last paragraph of Materials and Methods, sixth line, should read “…of filtered extract rapidly with 1 ml of 0.1 m catechol…”, not 0.1 ml.

Open Access

Commercial, ecological, and agrotechnical considerations have recently renewed interest in the use of physical rather than chemical means to maintain postharvest quality of horticultural crops. This review discusses prestorage heat treatments that protect against physiological disorders, enhance natural resistance to pathogen infection, reversibly inhibit fruit ripening, and permit flexibility in storage temperatures.

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Mature-green tomato (Lycopersicon esculentum Mill.) fruit, when kept for 3 days at 36, 38, or 40C before being kept at 2C for 3 weeks, did not develop chilling injury, while unheated fruit placed at 2C immediately after harvest did. When removed from 2 to 20C, the heated tomatoes had lower levels of K+ leakage and a higher phospholipid content than unheated fruit. Sterol levels were similar in heated and unheated fruit while malonaldehyde concentration was higher in heated fruit at transfer to 20C. The unheated tomatoes remained green, and brown areas developed under the peel; their rate of CO2 evolution was high and decreased sharply, while ethylene evolution was low and increased at 20C. In contrast, the heat-treated tomatoes ripened normally although more slowly than freshly harvested tomatoes: color developed normally, chlorophyll disappeared, and lycopene content increased, CO2, and ethylene evolution increased to a climacteric peak and K+ leakage increased with time. During prestorage heating, heat-stress ethylene production was inhibited, protein synthesis was depressed, and heat-shock proteins accumulated. There appears to be a relationship between the “heat shock response” and the protection of tomato fruit from low-temperature injury.

Free access

The benefits conferred by a prestorage heat treatment on poststorage quality of apples (Malus domestics Borkh.) were measured on `Anna', a non-storing early cultivar, and `Granny Smith', a long-storing late cultivar. The major benefit was a decrease in rate of apple softening, both during OC storage and during simulated shelf life at 20C. Soluble solids concentration was not affected by heat treatment, but titratable acidity was reduced. Ethylene production after heat treatment and storage was similar to or higher than that of control apples, but respiration was lower. The optimum temperature and time combination for prestorage treatment of both cultivars was 4 days at 38C.

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Abstract

Detectable calcium accumulation of the tissue started at 10−3M of the bathing solution and increased with increasing concentrations thereafter. Calcium solutions of 10−3 to 10−1M were effective in inducing metabolic changes in tissue: they decreased respiration and increased protein synthesis. Much of the accumulated Ca (90%) could be exchanged from the tissue with Mg without changing the metabolic effect of the Ca. Although high concentration of Ca was needed to move metabolically active Ca into the site of its action, most of the Ca accumulated on exchange sites was metabolically inactive.

Open Access

Abstract

A rapid sampling technique was developed to determine ethylene content of wood and buds of ‘Golden Delicious’ apple (Malus domestica Borkh.). The technique involves the use of a glass vial and 2 syringes per sample. One syringe was used to create a partial vacuum in a vial containing the sample tissue for a period of time, a second to remove a gas sample after the atmospheric pressure had returned to normal. On a n1/g basis, spur buds contained more ethylene than 1 or 2-year-old wood. Ethylene content of shoot bases remaining on the tree increased between 24 and 60 hours after pruning. Ethylene content of tissues sprayed with ethephon rose, then returned to normal after 9 days. The ethylene content of atmosphere in the Beltsville area fluctuated daily and should be considered in estimating absolute levels of ethylene generated by the tissue.

Open Access

Apple (Malus domestica Borkh. `Grand Alexander') fruit were stored immediately at 0C after harvest or after being held at 38,42, or 46C for 72,24, or 12 h, respectively. Half of each fruit lot was dipped in 1.5 % CaCl before storage. Heating did not appreciably affect Ca uptake into epidermal or cortical tissue. Calcium and heat treatments acted synergistically in reducing the severity of superficial scald and in retaining fruit firmness after 5 months of storage, relative to nontreated or nonheated Ca-dipped fruit.

Free access

Apples (Malus domestica Borkh. cv. Anna) were treated at harvest by a dip in 3% CaCI2 solution, heated for 4 days at 38C, or the two treatments combined, before being placed in OC storage. After removal of the apples from storage and holding them for 1 week at 20C, the combined treatment maintained fruit quality best. The fruit remained firmer than with either treatment separately, and peel yellowing and decreased titratable acidity caused by the heat treatment were less pronounced. Heat treatment alone maintained fruit firmness, while CaCI2 alone had no effect on fruit quality, although it raised the fruit calcium level more than the combined treatment in most experiments. Altering the temperature (0, 20, or 38C) of the CaCl2 dip did not change its efficacy. There was less soluble and more insoluble pectin in cell wall extracts of apples from the combined treatment than from other treatments. In addition, proportionally less Ca was present in the water-soluble pectin fraction of the combined treatment compared to other treatments, indicating different binding properties in the cell wall.

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`Anna' and `Granny Smith' apples (Malus domestics Borkh.) that were kept at 46C for 12 hours or at 42C for 24 hours before storage at 0C were firmer at the end of storage and had a higher soluble solids: acid ratio and a lower incidence of superficial scald than unheated fruit. These heat regimes produced results similar to those obtained by keeping fruit at 38C for 72 or 96 hours before storage. Prestorage regimes of 46C for 24 hours or 42C for 48 hours resulted in fruit damage after storage.

Free access