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P. Perkins-Veazle and J.K. Collins

The effects of retail-display packaging on strawberry fruit quality were studied using freshly harvested `Cardinal' strawberries. Fruit free from blemishes and disease were placed into plastic vented boxes, covered with vented plastic lids or plastic wrap, and placed at 1 and 5C overnight One-half of the treatments were removed from coolers, held at 25C for eight hours, returned to the coolers and evaluated over a 15-day storage period. The plastic overwrap greatly decreased weight loss during 15 days of storage; carbon dioxide reached 0.8 and 2% per mg fresh weight at 1 and 5C, respectively. Type of cover did not affect overall appearance or disease ratings. Exposure of fruit to 25C for eight hours led to no loss of overall quality. Storage of fruit at 50C led to greater disease incidence and loss of quality. The respiration rate of fruit warmed at 25C reached equilibrium after six hours, regardless of initial storage temperature. Fruit in vented dome-lid boxes had more weight loss than plastic-wrapped boxes at both temperatures.

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P. Perkins-Veazie and J. K. Collins

Okra pods are highly perishable due to a high respiration rate and chilling sensitivity. The purpose of this experiment was to evaluate okra cultivar response to package and storage temperature. Freshly harvested `Annie Oakley', `Blondy', `Burgundy', `Clemson Spineless' and `Emerald' okra pods were placed in plastic boxes and shrink-wrap bags. Pods were evaluated for weight loss, chilling injury and electrolyte leakage during 8 days of storage at 12.5 and 3°C. Weight loss was similar for all cultivars at both temperatures, but it was much less when pods were stored in bags compared to boxes. Percent electrolyte leakage was similar for all cultivars before storage. `Blondy' displayed the most severe chilling injury after 8 days of storage at 3C while `Emerald' had few symptoms of chilling injury. After 8 days of storage, all cultivars except `Emerald' had increased electrolyte leakage. These results indicate that okra pods have increased membrane permeability with chilling injury, and the degree of chilling injury may differ with cultivar.

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P. Perkins-Veazie and J.K. Collins

Okra stored at 3C in 12.7-pm high-density polyethylene (HDPE) bags developed less chilling injury than fruit stored in plastic boxes. Okra held in HDPE bags at 12.5C for 8 days had more decay and reduced overall appearance than fruit held in plastic boxes. `Emerald Green' okra lost more weight in storage than the other four cultivars regardless of temperature or storage duration, while `Blondy' had the most decay. `Annie Oakley' and `Clemson Spineless' had better shelf life than the other cultivars.

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P. Perkins-Veazie and J.K. Collins

Small fruit are rich in several types of phytochemicals, vitamins, and minerals. These compounds have health functional properties that may protect humans from cardiovascular disease and certain cancers. Several of these phytochemicals, such as dietary fiber, anthocyanins, and polyphenolics, also contribute to small fruit quality. Other components contribute to appearance and taste. Nonvolatile organic acids contribute to the perceived sourness of small fruit and changes in levels can alter visual color by affecting cellular pH and anthocyanin structure. The soluble sugars glucose, fructose, and sucrose contribute directly to the perceived sweetness of the fruit and provide carbohydrates for other metabolic functions such as phenolic and ascorbic acid synthesis.

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P. Perkins-Veazie and J.K. Collins

Application of modified-atmosphere storage (MA) (high carbon dioxide and/or low oxygen) extends the shelf life of several fruits. This study was done to determine the effects of MA on quality and flavor of blackberries. `Navaho' and `Arapaho' blackberries were harvested in 1998 and 1999, precooled overnight at 2 °C, and placed in 0.5-L treatment jars. Treatments of 15% CO2/10% O2 or of air (0.03% CO2/21% O2) were applied at 2 °C for 3, 7, or 14 days. After treatment application, jars were held at 2 °C for an additional 11, 7, or 0 days, respectively. Seven and 14 days of application of CO2 reduced the incidence of decayed and leaky berries by 10% to 20% for both `Arapaho' and `Navaho', but firm berries decreased 10% after 14 days of treatment. Titratable acidity was slightly lower, and pH higher, in control fruit but soluble solids content was not affected by treatment. Anthocyanin content was not affected by treatment in `Arapaho' berries but was lower in `Navaho' berries after 7 and 14 days of treatment. Samples taken for taste tests after 3 and 7 days of treatment had no off-odors or off-flavors. `Arapaho' and `Navaho' blackberries benefitted from high CO2 storage, with a minimum of 7 days of treatment application needed to increase marketable berries by 10%.

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P. Perkins-Veazie and J.K. Collins

Okra develops chilling injury after 4 to 5 days at 2C or 8 days at 5C. Intermittent warming has prevented or delayed chilling injury in warm season crops. The purpose of this experiment was to find a way to prevent or delay chilling injury in okra. Field grown `Annie Oakley', `Blondy', and `Clemson Spineless' okra pods were held constantly at 2, 5, or 10C or placed at 2C or 5C for 2 days followed by 2 days at 10C (2-10 and 5-10, respectively) then returned to their original temperature. After 8 days of storage, all boxes were placed at 20C for 1 day; color was measured with a colorimeter, and pods were rated subjectively for chilling injury. `Annie Oakley' and `Clemson Spineless' pods held at 2C were olive-green to brown; okra held at 2-10 was green and still marketable. Less chilling injury occurred to pods held at 5 and 5-10 compared to those at 2C. Pods held at 2-10, 5, or 5-10 had injury after 8 to 10 days of storage compared to 5 days at 2C. Although chilling injury could not be completely prevented in okra by intermittent warming, shelf life could be lengthened by cooling pods at 2C for no more than 2 days to eliminate field heat and reduce weight loss, followed by storage at a higher temperature.

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P. Perkins-Veazie and J.K. Collins

The red flesh of watermelon contains lycopene, a pigment with antioxidant properties that help prevent certain types of cancers. This experiment was done to determine cultivar variation in lycopene content, and the effectiveness of colorimetric measurements for predicting lycopene content. Ten ripe melons per cultivar of hybrid, open-pollinated, and triploid types were selected from field plantings at Lane, Okla. Melons were cut transversely and color measured with a colorimeter at three heart and three locule sites, in a counterclockwise rotation starting at the ground spot. For lycopene content, a 100-g sample of heart tissue was removed, extracted with a hexane-acetone-ethanol mixture, and lycopene concentration measured spectrophotometrically at 503 nm. Lycopene content varied among cultivars, from 33.96 μg·g–1 in `Crimson Sweet' to 66.15 μg·g–1 in `Crimson Trio'. Chroma and “a” colorimeter values were highly correlated with lycopene content (P < 0.001). Linear and quadratic regression of lycopene against colorimeter values yielded an R 2 of 0.55. Results indicate that, like tomatoes, watermelon cultivars vary widely in lycopene content. Colorimeter readings did not adequately predict lycopene values.

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P. Perkins-Veazie, J.K. Collins, M. Siddiq and K. Dolan

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.

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P. Perkins-Veazie, J.K. Collins and J.R. Clark

Promising white peach and nectarine selections, many with nonmelting flesh, from the Univ. of Arkansas breeding program were evaluated for fruit quality and flavor. About 20 kg of fruit, consisting of mature ripe and ripe stages, were harvested from 4- to 7-year-old trees in Arkansas and transported to Lane, Okla. Fruit were divided into two boxes per selection. One box was held at 5 °C for 8 days, then transferred to 20 °C for 4 days to induce chilling injury and was evaluated for storage quality. The other box was held at 20 °C for 4 days and fruit used for taste panels. Of the 14 nectarine and 12 white peach selections evaluated, one nectarine and four white peach selections had slight chilling injury. Flesh firmness of selections after storage ranged from 6 to 50 N. Taste panelist scores indicated that sweetness was associated with peach flavor in both nectarines and white peaches and that overall acceptability was dependent on sweetness, peach flavor, and low tartness. Ten of the white peach selections were equal to or better in overall acceptability compared to `Summer Pearl' and `Carolina Belle' cultivars included in the study. Panelists did not consider firm texture to be detrimental to overall acceptability. Results indicate that many of the breeding lines used in this study had fruit equal to or better than currently available cultivars in storage life, firmness, and sweetness.

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P. M. Perkins-Veazie, J. K. Collins and J. R. Clark

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.