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- Author or Editor: P.M. Perkins-Veazie x
The effectiveness of microorganisms applied in production of vegetable transplants has had mixed results. Bell pepper (Capsicum annuum L.) transplants were grown in a greenhouse using organic methods and the organic-certified potting mix was inoculated, or not, with beneficial bacteria or arbuscular mycorrhizal (AM) fungi, or both. Other transplants were grown in the same greenhouse with a conventional potting mix, which was not inoculated. Transplants were established in the field at various planting dates in a Bernow or Stigler soil and grown using conventional or organic methods. Pod yield and nutrient contents were determined. Yields of organically grown plants were similar to those of conventionally grown plants when both were grown on the Bernow soil. When grown on both soil types, yield was higher for the Bernow than for the Stigler soil. Treatment had little effect on pod mineral content. Chlorophylls, total carotenoid, and vitamin C contents of pods from plants grown on the Stigler soil were generally lower than those from plants grown on the Bernow soil. Average pod fresh weight for plants developed from seedlings inoculated with beneficial bacteria or AM fungi was greater than that from plants developed from conventionally grown seedlings. Inoculation did not improve fresh pod weights over that from plants developed from organically grown, but not inoculated, seedlings. Amending potting mix with the microorganisms tested did not provide extraordinary benefit or detriment for use in production of bell pepper.
Most watermelon in the U.S. is consumed fresh. Development of value-added products from watermelon is desirable for new market niches, and provides alternative markets for fruit that are cosmetically undesirable for the fresh market. The objective of this experiment was to determine if different processing techniques changed the lycopene and quality aspects of juices and concentrates. Watermelon flesh was macerated, followed by holding at room temperature (no heat) or heating to 50 °C. Macerate was then placed in a hydraulic press to obtain juice. Adding heat to macerate increased juice yield by 1% to 2% and increased lycopene content by 1 to 2 mg·kg–1. The residual pomace (waste from juicing) also contained lycopene, about 110% of that found in the juice, or 10% from the original macerate. In a second experiment, juice was subjected to pasteurization, which caused a slight loss of lycopene and beta-carotene compared to the unpasteurized juice. In a third study, juice was concentrated to 42 °Brix using either 40 or 50 °C heat treatments, followed by pasteurization. Heating juice to 50 °C concentrated the lycopene by 17% compared to heating to 40 °C. Pasteurization increased the lycopene content of the 40 °C concentrate by 10% but not of the 50 °C concentrate. In summary, the addition of heat at various steps during processing and pastuerization of watermelon concentrated but did not degrade lycopene. Additionally, the residual pomace created from juice manufacturing is a concentrated source of carotenoids and may have potential use as a value added nutraceutical product.
A study was conducted to characterize the quality of seedless and seeded watermelon. The seeded cultivars 'Jubilee', 'Black Diamond' and 'Allsweet' were compared with seedless 'King of Hearts' for firmness, lycopene content, rind thickness, soluble solids concentration (SSC), ascorbic acid, sugar composition, sweetness index and sensory qualities. 'King of Hearts' melons had higher firmness and lycopene values but a lower sweetness index compared with the other cultivars. 'Black Diamond' and 'Jubilee' cultivars had greater rind thickness compared to the other cultivars. 'Allsweet' and 'Jubilee' fruit had the highest ascorbic acid concentration. 'Black Diamond' had greater fructose and glucose levels than 'Jubilee' or 'King of Hearts' but was lowest in SSC. Untrained taste panelists preferred 'Jubilee' and 'Allsweet' melons. In this study, SSC, sugar composition, sweetness index or firmness were not good indicators of watermelon preference.
Blackberry fruit are considered highly perishable, having an average shelflife of 2 to 3 days. Fruit of erect blackberry cultivars were stored at 2C for 7 days to determine shelflife and quality changes. Weight loss was 1.8 and 3.4% after 3 and 7 days storage, regardless of cultivar or color stage. Soluble solids concentration (SSC), titratable acidity (TA), anthocyanin content, and skin firmness did not change during storage, but differed between ripeness stages and cultivars. Mottled (50% black) fruit were low in SSC and high in TA compared to shiny or dull black fruit. All dull black fruit were rated softer and lower in overall appearance after storage compared to shiny black fruit. `Choctaw' fruit were less firm and rated softer and of marginal appearance after 7 days storage while `Navaho' fruit remained firm and highly acceptable. Ethylene production ranged from 0.4 (`Navaho') to 2.8 nl/g-h (`Choctaw'). Results indicate that erect blackberry fruit harvested at the shiny black stage are of acceptable quality and have excellent shelflife potential.
High populations of melon aphid (aphis gossypii) reduce cantaloupe plant growth and yield; effects on subsequent fruit quality are unknown. The purpose of this study was to evaluate fruit quality from plants with high and low aphid populations. Up to 50% of melons from plants having high aphid populations were unmarketable due to surface sooty mold. Melons from plants with high or low aphid populations, but not cultivars, were similar in flesh quality. The internal color of `Perlita' and `Sweet Surprise' was a more yellow hue while that of `TAM Uvalde' was more orange. `Sweet Surprise' melons were lower in percent soluble solids concentration and titratable acidity, but were higher in mg fructose/ml juice compared to the other cultivars. A trained taste panel of 30 people evaluated melons from 2 cultivars showing little damage from melon aphid infestations and from 2 cultivars exhibiting high damage. All melons had similar taste qualities with acceptable sweetness, flavor, odor and texture. These results show that high aphid populations deleteriously affect cosmetic appearance, but not flesh quality, of melons.
`Navaho' is a thornless erect tetraploid blackberry. Fruit were harvested at 6 color stages to characterize the changes occurring during ripening. Fresh and dry fruit weights indicated double sigmoidal growth while pyrene growth was single sigmoidal. Respiration was of a climacteric nature and ethylene production peaked at 0.4 nl/g-h at the dull black stage. Free ACC and ACC oxidase did not increase until the shiny black stage, corresponding with the first detectable ethylene production. Anthocyanin (cyanidin-3-glucoside) remained at low levels until fruit were 50% black (mottled). Skin and receptacle firmness decreased sharply between the mottled and black stages of ripeness. Soluble solids concentration continued to increase, and titratable acidity to decrease, into the dull black stage. These results indicate that most ripening aspects associated with edible quality occur late in `Navaho' fruit development, but prior to stimulated ethylene production.
Radicchio, also known as red-leaved chicory (Cichorium intybus L.), is a high value vegetable crop. Few postharvest characteristics have been described for this crop. Five cultivars of radicchio were held at 1 and 10C in plastic boxes or shrink-wrap bags to determine postharvest quality changes. Weight loss was similar at both temperatures for all cultivars. Major quality losses of radicchio held in shrink-wrap or plastic boxes at 1C were caused by leaf browning. Shrink-wrapping prevented leaf shrinkage and bleaching, but enhanced decay at 10C. The respiration rate of radicchio heads held at 1C was initially 7.4 ml· CO2 kg-1 · h-1, then fell to 3 ml CO2 ·k g-1 · h-1 after 7 days of storage at 1C. Respiration at 10C was maintained near 19 ml·k g-1· h-1 through the duration of the experiment. Shrink-wrapped radicchio held at 1C had marketable quality for 5 weeks.