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  • Author or Editor: H. P. Fleming x
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Abstract

A procedure is described for studying routes of liquid entry into and movement within pickling cucumber fruit (Cucumis sativus L. cv. Chipper). The internal gases of the fruit are exchanged with oxygen in a closed container. Fruit are then covered with 0.5% aqueous safranin O and allowed to stand for a few hours. Liquid was shown to enter the fruit through epidermal regions of greatest stomatal density, which are near placental tissue. The dye solution then moved through intercellular spaces and cell walls of placental and other mesocarp tissues and vascular elements. The stain facilitated delineation of stomata and visual observation of routes of liquid movement. Liquid entrance apparently is induced due to a partial vacuum created within the O2-exchanged and liquid-submerged fruit.

Open Access
Evaluation of Pickles from Cucumber Plants 1 Treated with 2-Chloroethylphosphonic Acid

Abstract

Cucumbers from plants of a gynoecious cultivar treated with 0, 240, or 480 ppm 2-chloroethylphosphonic acid (Ethrel)were made into fresh-pack pickles and brine stock and evaluated by experienced judges. Fruit from Ethrel-treated plants were shorter than those from untreated plants. Otherwise there were no significant differences in appearance, flavor, texture, firmness, bloater formation, or acceptability of the processed product.

Open Access

Abstract

A method was developed for determining internal gas pressure changes of pickling cucumbers (Cucumis sativus L.) during brine storage. Internal pressure decreased by 55 mm Hg during the first hour after the control fruit had been submerged in brine and then gradually increased over the next 2 hours to about the level of atmospheric pressure that had existed immediately after brining. With cucumbers that were gas-exchanged before brining, the pressure decreased by a maximum of 145 mm Hg when O2 was the exchange gas, and increased slightly when N2 was the exchange gas. Pressure changes in O2-exchanged cucumbers corresponded with changes in the level of brine that surrounded the fruit, suggesting that liquid entered the fruit as a consequence of the partial vacuum. O2-exchanged, brined cucumbers acquired a translucent, cured appearance, due apparently to filling of the intercellular gas spaces with liquid. Mechanically induced vacuum failed to induce the cured appearance. Respiratory conversion of O2 to CO2 in control and in O2-exchanged fruit, with greater dissolution of the CO2 than the O2 which it replaced, is thought to account for the partial vacuum that develops in brined cucumbers.

Open Access

Abstract

Scanning electron microscopy revealed the presence of stomata, trichomes, scars left by detached trichomes, and epidermal cells on the surface of fresh, pickling cucumbers. Size, frequency and distribution of stomata were determined. Stomata, recessed several qm, were the only apparent, natural openings in the epidermis for gas exchange. Stomata were most numerous in the middle (20.2/mm2), less in the blossom end (10.4/mm2) and essentially absent in the stem end section of large (3.8–5.1 cm diameter), ‘GY14’ fruit. Stomatal frequency on large fruit was only about one-third that on small (1.9–2.7 cm diameter) fruit, but the stomatal index for the middle section of each size was similar (0.17–0.18). Large ‘GY14’ fruit were estimated to contain 130,000 stomata, with potential stomatal pore area (assuming open guard cells) representing 0.062% of the fruit surface

Open Access

Abstract

Leaves of Cucumis sativus L. contained predominantly, non-reducing sugars which included verbascose, stachyose, raffinose and sucrose. Glucose and fructose were also present. The major sugars of fruit were glucose, fructose, and sucrose. Stachyose was present in small fruit (5 to 7 g fresh weight), but no soluble galactose-containing saccharides were found in larger fruit. Other plant parts also contained the raffinose saccharides. The identities of these sugars were established by partial enzymatic hydrolysis and paper chromatographic examination of the hydrolytic products. Four species of lactic acid bacteria from cucumber fermentations were able to ferment stachyose, raffinose, sucrose, melibiose, galactose, glucose, and fructose.

Open Access