To determine if postharvest treatments of 1-methylcyclopropene (1-MCP) retard the senescence of highbush blueberries (Vaccinium corymbosum L.) removed from storage, `Burlington' (early) and `Coville' (late) fruit were harvested from four experimental sites and treated for 24 hours at 20 °C with 0 (control), 25 (low), 100 (medium), or 400 (high) nL·L-1 of 1-MCP. All fruit were then stored in a controlled atmosphere of 10-15 kPa O2 and 10 kPa CO2 at -1 to 1 °C for 4, 8, and 12 weeks, followed by a 20 °C shelf-life of up to 20 days. During the shelf-life period immediately after harvest and those following each storage removal, percent marketable fruit (PMF) were calculated daily as: [fruit in good condition]/[total berry number] × 100. Changes in PMF were not affected by 1-MCP treatment; hence, we conclude that 1-MCP at rates up to 400 nL·L-1 does not alter the shelf-life quality of the highbush blueberry cultivars tested.
John M. DeLong, Robert K. Prange, Conny Bishop, Peter A. Harrison, and Daniel A.J. Ryan
J.A. Kirkpatrick, T.E. Morelock, L.R. Howard, and F.J. Dainello
Fresh-market spinach production has risen in the United States in the past few years as well as total value of the crop. Increased crop value may be attributed to more “value added” spinach products being produced and marketed. Public awareness of nutrition is rising due to more information being distributed concerning cancer prevention, antioxidants, and neutraceuticals. Spinach is high in the carotenoids beta-carotene and lutein, a known antioxidant for the prevention of age-related macular degeneration (AMD). It is also high in vitamins A, C, E, and folate, fiber, and the mineral iron. In this respect, spinach producers have an advantage over growers of salad vegetables such as lettuce. While this is an advantage, more innovative “value added” methods of marketing this product to the consumer are needed. A dark-green, semi-savoy spinach type developed at the Univ. of Arkansas was studied to determine shelf-life and storage capabilities of root cut plants in transparent clamshell containers. Plants were held at temperatures ranging from 1 to 6 °C. Leaf turgidity and visual characteristics were rated on a 1 to 5 scale. Acceptable characteristics and shelf-life of spinach stored in clamshell containers were seen up to 14 to 21 days when plants were stored at or near 1 °C. These results indicate that spinach packaged in transparent clamshell containers will maintain an acceptable shelf-life and could be beneficial to fresh market spinach producers.
W.C. Lin and P.A. Jolliffe
The importance of light intensity and spectral quality on fruit color and shelf life of long English cucumber (Cucumis sativus L.) was studied in four greenhouse experiments. The intensity of cucumber greenness was measured nondestructively by video imaging, and shelf life was measured by visual observation of incipient yellowing. In the summer, filters were used to cover individual fruit to reduce light intensity reaching the fruit surface. The lower the light intensity incident on a cucumber, the shorter its shelf life. The average shelf life was 8, 5, or 1 days for cucumbers receiving 100%, 66%, or 31% of natural daylight, respectively. The fruit that were covered with a filter transmitting red (R) light were greener (low grey level via video imaging) than those with a far-red (FR) filter. In the fall, fruit receiving spectral R lighting from fluorescence tubes were greener and had a longer shelf life than those receiving FR lighting from incandescent bulbs. In the winter, high-pressure sodium (HPS) lighting was necessary to supplement natural daylight for crop growth and production. Under HPS, R and FR lighting produced the same fruit greenness and shelf life. In the spring, R-lighted fruit had longer shelf life than FR-lighted ones, although fruit color at harvest was similar. In these four experiments, postharvest shelf life of long English cucumber was generally related to fruit greenness upon harvest. The data suggest the importance of an open canopy in improving fruit greenness and shelf life of greenhouse-grown cucumbers.
Fouad M. Basiouny
Fruit of Rabbiteye blueberry (Vaccinium ashie Reade cv. `Tifblue') were hand-picked at horticultural maturity and received postharvest liquid coating and heat treatments at 37.7°C for 30 minutes. After precooling for 2 hours and subjected to the treatments, fruit were placed in ventilated card boxes and stored at 1 ± 2°C and 90% to 95% relative humidity for 4 weeks. Heat, liquid coating, or both benefited fruit by reducing storage moisture loss and prolonging fruit shelf life compared to nontreated fruit. However, combining liquid coating with heat treatment did not result in higher differences in storability or fruit quality characteristics.
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.
Hector Nunez-Palenius*, Daniel Cantliffe, Harry Klee, and Donald Huber
`Galia' is a high-quality muskmelon cultivar that is grown in green-houses or tunnels to maximize fruit yield and to help improve fruit quality. Maximum fruit quality and flavor are achieved when `Galia' are harvested at maturity. This however leads to reduced firmness and short shelf life. In vitro regeneration and transformation of `Galia' melon is a strategy that can be used to increase fruit shelf life. Melon cotyledons were transformed with the ACC oxidase gene in antisense orientation according to the protocol described by Nunez-Palenius et al. (2001, 2003). Experiments were conducted to compare fruit quality parameters between transgenic (TT) and wild type (WT) fruits from plants grown in greenhouse conditions. The melon plants were grown using commercial growing practices that included pruning and training to one vertical stem and the use of soilless media and drip fertigation. Wild type fruits were harvested at 37, 42, and 50 days after pollination (DAP), whereas transgenic fruits were harvested at 42, 50, and 56 DAP. TT fruits were harvested with that delaying period since their ripening process was slower than WT. Thirteen preharvest parameters were evaluated in transgenic and wild type fruits. Wild type and transgenic weight, lenght, width, soluble solids, tritatable acidity, pH, firmness, flesh thickness, seed cavity size and seed number parameters were not significantly different. Ethylene production and ACC oxidase from 42 DAP wild type fruits were greater than from transgenic fruits. Transgenic (ACC oxidase) galia melon fruits had a delayed fruit ripening process compared with wild type fruits.
L.G.M. Gorris and H.W. Peppelenbos
There has been a recent upsurge in the application of modified atmosphere and vacuum packaging to extend the shelf life of food products that rapidly deteriorate. Although these techniques are mostly used with nonrespiring products, both offer considerable prospects for respiring products as well. Because not all commodities respire at the same pace, packaging conditions, such as the initial gas atmosphere applied, the type of packaging material used, and the storage temperature, require special consideration. Choosing the wrong packaging conditions may lead to loss of product quality and also may impair the microbiological safety normally associated with fresh fruits and vegetables. This paper stresses the importance of these considerations with modified atmosphere and vacuum packaging systems.
Titus M. Kyalo and H. Brent Pemberton
Rooted liners of Rosa cvs. Meijikatar and Meirutral were potted into 11 cm pots and placed into growth chambers. One chamber provided 14 hours of light with 30C/21C (day/night) air temperature (HTLD) and another chamber provided 8 hours of light with 21C/17C (day/night) air temperature (LTSD). PPF was 725 μmoles m-2 s-1 in both chambers. When plants were established, they were pinched and forced to flower. Simulated shipping for 4 days at 16C in darkness resulted in a shorter shelf-life when placed in an interior environment at 21C with a continuous PPF of 30 μmoles m-2 s-1 and compared to non-shipped plants. In addition, LTSD grown plants exhibited a shorter shelf-life than HTLD grown plants. When Meirutral plants were sprayed to runoff 24 hours prior to shipping, 2 mmolar (aminooxy)acetic acid (AOA) increased the shelf-life to the same length as the non-shipped plants and 2 mmolar silver thiosulphate (STS) increased the shelf-life to longer than the non-shipped plants. However, AOA did not increase shelf-life over that of shipped plants for Meijikatar whereas STS increased the shelf-life to that of the non-shipped plants.
Gustavo R. Rodríguez, Guillermo R. Pratta, Roxana Zorzoli, and Liliana A. Picardi
A cross was performed between Lycopersicon esculentum Mill. `Caimanta' and L. pimpinellifolium (Jusl.) Mill. accession LA722. Divergent-antagonistic selection for fruit weight and shelf life started in the F2 generation. Fruit shelf life showed transgressive segregation in this F2 generation. The selection process continued until the F6 generation, but we found that only fruit weight was responsive to selection. Seventeen recombinant lines (RILs) were analyzed for both traits. Nine of these RILs were obtained by the selection process. The other eight RILs were obtained by selfing without selection from the same F2 generation to assess random drift. Highly significant differences were found among these RILs for both fruit weight and shelf life. Random drift was as important as selection in producing different genotypes. Although fruit shelf life showed null response to selection in this interspecific cross, selfing and selecting has generated a new population of 17 recombinant genotypes for both fruit weight and shelf life. This experiment has demonstrated that wild tomato species offer breeders another possibility to enhance the genetic variability for fruit shelf life and fruit weight in tomato germplasm.
Teresa L. Walker, Justin R. Morris, Renee T. Threlfall, Gary L. Main, Olusola Lamikanra, and Stephen Leong
Muscadine grapes (Vitis rotundifolia Michx.), native to the southeastern United States, have a distinct flavor, and grocers are interested in marketing them as table grapes. Two studies using 'Fry' muscadines were conducted to assist the muscadine industry in providing quality table grapes. Study 1 (1998 and 1999) evaluated density sorting and relationships between maturity, color, soluble solids, firmness, shelf life, and sensory evaluation of grapes. Study 2 (1998) determined the effect of storage on quality attributes of different maturities of grapes and evaluated use of polyethylene bags to extend their storage. Density separation successfully sorted grapes by maturity. Muscadine berry color may allow for visual or electronic sorting to eliminate immature fruit. Sensory panelists could distinguish differences in maturities for all sensory attributes. In 1999 maturities 3 and 4 (≈24-33 soluble solids: acid ratio) were preferred overall by panelists. As maturity increased, soluble solids and pH increased, and acidity decreased. Firmness decreased as maturity and storage at 2 °C increased. Percent decay increased with maturity and storage time. Grapes stored in polyethylene bags had reduced decay. A chart developed from the 1999 data related berry color to soluble solids: acid ratio, soluble solids, tartaric acid, and pH. Data from these studies can be used by industry to establish harvest parameters and enhance marketability of 'Fry' muscadine grapes.