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Abstract
The titratable acidity of the locular and pericap portions of tomato fruits (incipient color stage) was determined before and after storage at 38°, 45°, or 50°F for 4 or 8 days. Acidity measurements were also made on similar fruits held at the above temperatures for 0, 4, or 8 days followed by 6 days at 70°.
The pericap and locular portions of fruits stored for 4 and 8 days at low temperatures had a higher titratable acidity after ripening than control fruits ripened without prior chilling. The per cent decrease in acidity during ripening was greatest for the unchilled fruit and least for the fruits chilled for 8 days. The pattern was the same for the 3 temperatures. There was an increase in acidity of fruits after 4 days of storage.
Abstract
The firmness of tissues of a transverse equatorial slice of fruits of ‘Flora-Dade’, ‘Walter’, ‘MH-1’, and ‘Homestead 24’ tomatoes (Lycopersicon esculentum Mill.) was determined at different stages of ripeness by use of an Instron Food Testing System. The outer, radial, and inner pericarp tissues of ‘Flora-Dade’ and ‘MH-1’ were firmer than those of ‘Walter’ when ripened 6, 8, or 10 days at 20°C after incipient color formation. ‘Walter’ tissues were intermediate in firmness between ‘MH-1’ and ‘Flora-Dade’ at the mature green stage, but had softened much more than either at the incipient color stage. Most of the softening of the tissues of the three cultivars had occurred by 4 days after incipient color. The placental tissue of ‘Homestead 24’ fruit was much firmer than that of ‘Walter’ and ‘Flora-Dade’ over a period of 7 to 19 days after incipient color stage, although the outer pericarp tissue was much softer than that of the latter two.
Abstract
Mature-green fruit of tomato (Lycopersicon esculentum Mill.) were stored for up to 7 weeks at 20°C in 2.5, 5.0 or 20% O2 with certain samples ripened for 7 days more. Low O2 delayed ripening and consequently delayed softening in proportion to the O2 level and storage duration.
Abstract
In leaves of carrot (Daucus carota L.) treated with 120 ppm 2-(4-chlorophenylthio)-triethylamine hydrochloride (CPTA), increased lycopene levels were found. Significant amounts of carotenes tentatively identified as gamma- and delta- were also found. Alpha- and beta-carotene levels were reduced. The effect of CPTA was modified by temperature and genotype. The data suggest that lycopene is a precursor of the carotenes mentioned and that alpha-ionone cyclase has a higher optimum temperature than beta-ionone cyclase.
Abstract
Fruit quality characteristics of ‘Healani’, ‘Homestead-24% ‘Walter’, and ‘Flora-Dade’ tomatoes (Lycopersicon esculentum Mill.) were determined during the spring and fall season from plants fertilized with 0, 93, 186, 372, and 744 kg K/ha. Reducing sugars, dry weight, and pH were higher in the spring, while titratable acidity was higher in the fall. ‘Healani’ had the highest and ‘Flora-Dade’ had the lowest soluble solids, reducing sugars, dry weight, and pH in each season. Titratable acidity increased with increasing K rate during both seasons, while pH decreased with increasing K rate only during the spring. Each cultivar, except ‘Flora-Dade’, had a higher reducing sugar content with 744 compared to 0 kg K/ha in the spring.
Abstract
Fruits of the firm cultivars ‘Florida MH-1’ and ‘Flora-Dade’ and the less firm cultivar ‘Walter’ tomato (Lycopersicon esculentum Mill.) were harvested at the mature green stage of maturity and held at 20°C. After ripening at 20°C for 7, 14, and 21 days, ‘Florida MH-1’ and ‘Flora-Dade’ fruits were firmer than ‘Walter’ fruits. ‘Flora-Dade’ fruit were as firm at 21 days as fruit of ‘Walter’ at 7 days. ‘Florida MH-1’ fruit were as firm at 14 days as those of ‘Walter’ at 7 days. There was no relation between fruit color and firmness. A seasonal effect on firmness at 7 days was found for ‘Walter’ and ‘Florida MH-1’ but not for ‘Flora-Dade’.
Abstract
‘Healani’, ‘Homestead-24’, ‘Walter’, and ‘Flora-Dade’ tomatoes (Lycopersicon esculentum Mill.) were grown with 0, 93, 186, 372, or 744 kg K/ha during spring and fall to determine the influence of K rate, cultivar, and season on the separate fruit disorders of graywall (GW) and blotchy ripening (BR). Susceptibility to GW was determined by inoculating a GW-inducing type of bacteria, Erwinia herbicola (Dye), into the outer pericarp of immature green fruit. All 4 cultivars developed more GW without added K than with it during the spring season. In both field and greenhouse conditions, ‘Flora-Dade’ and ‘Homestead-24’ were more resistant to GW than ‘Healani’ and ‘Walter’. Natural GW, contrasted to bacterially induced GW, occurred in ‘Healani’ and ‘Homestead-24’ fruit grown with low K concentrations in a sand culture experiment. Both cultivars were free of natural GW with the high-K treatment. ‘Flora-Dade’ was resistant to natural GW under all K treatments. Fruit from all cultivars had significantly less BR with K fertilization in both seasons. External blotchy ripening (EBR) and internal blotchy ripening (IBR) were more severe in the spring than in the fall. ‘Healani’ showed resistance to yellow shoulder, the primary EBR symptom, which was severe during the spring in all other culti vars. ‘Healani’ was generally the most BR-resistant cultivar and ‘Flora-Dade’ the most BR-susceptible. Pericarp K concentration increased with K rate in all cultivars during both seasons, but differences in susceptibility to BR between cultivars were not associated with differences in pericarp K, Ca, Mg, or P content.
Abstract
The possibility of using seed adenosine triphosphate (ATP) content as an indicator of seed vigor was studied. Seeds of corn (Zea mays L.), cucumber, (Cucumis sativus L.), onion (Allium cepa L.), and radish (Raphanus sativus L.) with seed moisture contents of 5, 10, 15, 20, or 25% were stored at temperatures of −10°, 5°, 15°, 25°, or 35°C for 0, 2.5, 5, and 10 months. Germination and seedling vigor decreased as storage time, temperature, and moisture level increased. Viability was lost in most seeds after 2.5 months at high temperature (25-35°) and high moisture (20-25%) contents. Seed stored at 5° and 5% moisture maintained the highest viability and seedling vigor over the 10-month storage. Low temperature (−10°) and high seed moisture levels (20-25%) reduced germination and vigor of radish seed. Seed ATP content did not correlate with reduced germination or vigor in any species. ATP concentrations consistently decreased over the 10-month storage period in all seeds stored at −10°. However, this trend did not correlate with the other vigor indices.
Abstract
The outer pericarp thickness of fruit of tomato (Lycopersicon esculentum Mill) ripened off the vine depended upon the maturity of the fruit when harvested. Immature fruit has thinner outer pericarps than fully mature green fruit. Similar results were obtained with 4 cultivars and 3 fruit sizes. The pericarp thickness did not change during a 6-day ripening period for any maturity. There was no difference in number of cells in the outer pericarp due to maturity or fruit size.
Abstract
Juice made from carrots stored at 20, 25, 30 or 35°C for 0,2,4 or 8 days contained negligible amounts of nitrite when sampled immediately. The bacterial populations were higher in juice made from carrots stored for longer periods and at the higher temperatures. Juices incubated at 35°C for 4 hours accumulated nitrite in amounts that tended to correspond to the bacterial populations in the fresh juices.