Search Results
Abstract
Citrus groves cover nearly a million acres of the Florida ladscape, and the citrus industry accounts for about a third of the State' agtricultural income. Agricuture and tourism have in recent years contributed about equally to income produced in Florida.
Abstract
We all pay lip service to the concept that fruits and vegetables are alive. Nevertheless, very little attention is paid to what must be a major trauma for most of them, being suddenly cut off at harvest from the water supply that has hitherto sustained them. While on the plant, the organs that we call fruits and vegetables participated in a dynamic traffic in water due to transpiration and to withdrawal of water by the plant in times of stress (40). At harvest, this suddenly ceases and for water, as well as other essential nutrients, they have to become what Biale has called “self sufficient harvested fruit” (8). This transition is minimal for those that are storage organs physiologically prepared for a long resting period (e.g. onions, cabbage, pumpkins, beets, carrots, potatoes) or are fruits 2 that form a complete abscission layer preparatory to inevitable dehiscence (e.g. nuts, apples, pears, persimmons, plums, pomegranates, lychees). The water relations transition is maximal for those severed from the parent plant regardless of botanical independence or physiological maturity (e.g. okra, cauliflower, asparagus, corn-on-the-cob, leeks, celery, green beans, parsley, lettuce, green peas). Fruits that have a long harvest period from a single bloom (oranges, grapefruit, avocado) are intermediate. At the time of the fruit’s sudden severance from a hitherto assured water supply, humidity (as distinct from root-supplied water) becomes of critical importance. The trauma of this onset of harvested life should be a consideration in the handling of horticultural products.
Abstract
Humidity as related to horticulture is discussed in terms of: ways of expressing humidity levels; physical properties of water vapor; and temperature-humidity and air circulation-humidity interactions. The role of humidity in transpiration, killing freezes, and storage and transport of fruits and vegetables is discussed. Also given are sources of information on methods of recording and controlling humidity in postharvest applications.
Abstract
Activated charcoal or Polyclar AT removed sodium o-phenylphenate (SOPP) from laboratory-prepared Solutions and citrus packinghouse effluents. Activated charcoal at 0.25 g/100 ml of 100 ppm SOPP removed 99.6% SOPP, while Polyclar AT at 10 g/100 ml of 100 ppm SOPP removed 95% of the phenolic fungicide. Efficiency of SOPP removal declined when the amount of added Polyclar was reduced below 10% or the concentration of SOPP in treated Solutions exceeded 100 ppm.
Abstract
Chilling injury (CI) drastically limits the storage and marketing of limes and grapefruit. Previous studies showed that CI of grapefruit can be largely controlled for ca. 3 weeks by high (up to 10%) CO2 and very high (>95%) relative humidity. Atmospheres established within 7 packaging films differentially permeable to CO2 and O2 were tested for control of CI. Polyvinylchloride and cast vinyl films were tested in detail. Grapefruit CI could be prevented for 1 month at 4.5°C (40°F) by sealing within these films. Even though the films were broken upon removal of the fruit, subsequent shelf life was considerably extended. The fungicide thiabendazole (TBZ) significantly reduced the visible lesions of CI, thus confirming a recent Israeli report.
Abstract
Effects of storage time, temperature, fruit preparation, time of harvest and number of diphenyl pads per carton with ‘Dancy’ (Citrus reticulata Blanco) and ‘Sunburst’ a seedling from ‘Robinson’ × ‘Osceola’, each C. reticulata × (C. paradisi Macf. × C. reticulata) tangerines were studied to determine the amount of diphenyl absorbed and extent of decay. Storage of ‘Dancy’ and ‘Sunburst’ at 4°C for up to 4 weeks with 1 or 2 diphenyl pads resulted in diphenyl residues less than the U.S. legal tolerance of 110 ppm. However, storage of both cultivars for 2 weeks at 21°C with 2 diphenyl pads resulted in residues exceeding this tolerance limit. Decay and diphenyl residues both tended to be higher for ‘Dancy’ than for ‘Sunburst’. ‘Dancy’ tangerines stored for 4 weeks at 21°C all decayed. Statistical examination of 2 harvests of ‘Sunburst’ showed that early harvested fruit were less susceptible to decay but prone to absorb higher amounts of diphenyl.
Abstract
Chilling injury (CI) of ‘Marsh Seedless’ grapefruit was reduced by a preharvest spray of benomyl (Benlate) but not of Vapor Gard (VG) pinolene antitranspirant Postharvest treatments with benomyl and thiabendazole (TBZ) also reduced CI. The effect of high CO2 atmospheres (up to 20%) induced under 0.0254 mm (1 mil) PVC film varied sharply with picking date. CI was almost eliminated in such atmospheres in early and midseason pickings but accentuated in the late (postbloom) picking. Modified atmospheres tended to increase decay regardless of picking date.
Abstract
The long voyage of Florida grapefruit (Citrus paradisi Macf.) to Japan and extended marketing periods on arrival were associated with a problem with excess diphenyl (biphenyl) residues. Japanese food additive regulations have necessitated reliance on the vapor-phase fungistat diphenyl, for which residues in the fruit increase with time after packing. Residues in some shipments unexpectedly exceeded the Japanese tolerance of 70 ppm. Experiments designed to identify the effect of various factors on diphenyl residues are reported. The amount of diphenyl, temperature before refrigerated transit and exposure time, especially before refrigeration, affected diphenyl residues. Air filtration had little effect. Very early season grapefruit (harvest started before legal maturity) in August and September 1978 absorbed excessive diphenyl residues. Excessive absorption of diphenyl by grapefruit is apparently characteristic of very early fruit.