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Basavaraj Girennavar*, Narayan Bhat, Jennifer Brodbelt, Michael Pikulski, G.K. Jayaprakasha, and Bhimanagouda S. Patil

Grapefruit juice contain furanocoumarin derivatives which are known to interact with various drugs such as felodipine, leading to the increased bioavailability. Due to very low concentrations of furocoumarin in grapefruit juice, isolation of these compounds has been a challenge to researchers. Five grapefruit (Citrus paradisi Macf.) varieties such as `Marsh White', `Duncan', `Rio Red', `Orange Flesh', and `Mexican Red' were harvested and analyzed. Samples were extracted successively three times with ethyl acetate until all furocoumarins were extracted. The dried extract was reconstituted in methanol and used for quantification using high-performance liquid chromatography. Furanocoumarins were quantified by gradient elution with methanol and water as mobile phase with a flow rate of 1.1 mL/min at 240 nm. The concentrations of bergamottin, dihydroxybergamotin (DHB) and dimer of DHB were shown to distinctly differ among varieties. Red colored grapefruit showed lower concentrations of the furocoumarins compared to white colored grapefruit. Among the five varieties, `Rio Red' grapefruit contain lower concentrations of bergamottin and DHB. Further studies are continued to quantify other dimers and commercial varieties. Knowledge of furocoumarin levels in grapefruit may eventually help the consumer to make decision about eating grapefruit and/or drinking juice while taking certain medications.

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Fairuz. El-Wazir, Dangyang Ke, and Adel A. Kader

The tolerances (based on time before detection of off-flavor) of nectarine and peach cultivars to an insecticidal controlled atmosphere of 0.25% O2 (balance N2) at 20C were 2.8, 4.0, 4.0, 4.4, 5.1, and 5.3 days for `John Henry' peaches, `Fantasia' nectarines, `Five Red' peaches, `O'Henry' peaches, `Royal Giant' nectarines, and `Flamekist' nectarines, respectively. The greater sensitivity of `John Henry' peaches to low O2 stress was associated with a higher respiration rate; faster accumulation rates of acetaldehyde, ethanol, and ethyl acetate; and a more mature and larger fruit. The tolerances of `Fairtime' peaches to 0.21% O2 + 99% CO2 at 20C, 0.21 O2 + 99% CO2 at 0C, and 0.21% O2 at 20C were 3.8, 5.0, and 6.0 days respectively. There was a good correlation between tolerance of nectarines and peaches to insecticidal atmospheres and the accumulation rates of acetaldehyde (r=-0.94, p<0.01) and ethanol (r=-0.88, p,0.01).

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J.P. Mattheis and D.A. Buchanan

Apple fruit storage lie is prolonged by low-oxygen cold storage, however, ethanol accumulates when oxygen concentration is reduced below the Pasteur point, Upon return to aerobic conditions, dissipation of ethanol occurs due to physical (evaporation) and biochemical processes. Oxidation of ethanol by apple fruit occurs at a slow rate, but ethanol also serves es a substrate for fruit volatile synthesis. This study was conducted to determine changes in concentrations of ethanol and other non-ethylene apple fruit volatiles following periods of anaerobiosis. `Delicious' apples were obtained from a commercial warehouse and stored at 0.05% O2, 0.2% CO2 and 1 C. One day following return to ambient oxygen conditions, several volatiles were identified from anaerobic fruit that were nor produced by the control fruit. All were eaters that contained an ethyl group as the alcohol-derived portion, These included ethyl acetate, ethyl butyrate, ethyl 2-methyl butyrate, ethyl hexanoate and ethyl octanoate. Several esters produced by the controls were not detectable from anaerobic fruit including butyl butyrate, butyl 2-methyl butyrate, propyl hexanoate and 3-methyl butyl hexanoate. After 7 days ripening at 20 C, the amount of ethanol and the additional ethylesters was reduced in anaerobic fruit. Synthesis of esters produced by control fruit but nor by anaerobic fruit during the initial volatile sampling had resumed after 7 days.

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A.A. Kader, D. Ke, M. Mateos, and E. Yahia

Fruits of `Bartlett' pear (Pyrus communis L.) at green (preclimacteric) and yellow (postclimacteric) stages were kept in 0.25% O2 (balance N2), 80% CO2 (balance O2), or 0.25% O2 + 80% CO2 (balance N2) for 1, 2, or 3 days followed by transfer to air at 20C for 3 days to study the effects of these controlled atmosphere (CA) treatments on anaerobic products and enzymes. All the three CA treatments caused greater accumulation of ethanol, acetaldehyde, and ethyl acetate than the air control. The postclimacteric pears were more sensitive to CA treatments as indicated by occurrence of skin browning, enhanced activity of pyruvate decarboxylase, and higher concentrations of the anaerobic volatiles. For the preclimacteric pears, the 0.25% O2 treatment dramatically increased alcohol dehydrogenase (ADH) activity, which was associated with the induction of one ADH isozyme. Exposure of preclimacteric pears to 80% CO2 slightly increased ADH activity while treatment with 0.25% O2 + 80% CO2 resulted in lower AD11 activity than 0.25% O2 alone.

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Clark Wilson, G.K. Jayaprakasha, and Bhimanagouda Patil

Open column chromatography is an effective and common technique for the separation and purification of chemical constituents. Limonoids are found in significant quantities in citrus fruits. Citrus limonoids have documented anti-cancer activity in several types of cancer, such as breast, colon, skin, and neuroblastoma in animal models and in vitro cell culture studies. Furthermore, limonoids have shown anti-inflammatory properties and inhibitory effects on bone resorption. In addition to many potential health benefits, limonoids have also shown antifungal and insect anti-feedant properties. To meet the large demand of limonoids for bioactivity studies, defatted grapefruit seeds were extracted using acetone and concentrated under vacuum. The dried extract was loaded onto a silica gel column and eluted with mixtures of dichloromethane and ethyl acetate with increasing polarity to obtain three compounds. The purity of the compounds (1–3) have been analyzed by HPLC and the structures have been identified by using NMR spectra and mass spectra as nomilin, limonin, and deacetylnomilin, in respective order of elution. The results will be presented in greater detail on the poster. This project is based upon work supported by the USDA-CSREES under Agreement USDA IFAFS #2001 52102 02294 and USDA #2005-34402-14401 “Designing Foods for Health” through the Vegetable & Fruit Improvement Center.

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Yuji Noguchi, Tatsuya Mochizuki, and Kazuyoshi Sone

The use of wild species as breeding materials was tried for expanding hereditary variation in strawberry. Some interspecific hybrids setting large fruits with peculiar aroma have been bred by pollination of F. vesca to F. xananassa. Although Asian wild diploid strawberries such as F. nilgerrensis or F. iinumae have not been exploited as a breeding material until the present, the crossing test between cultivated strawberries (8x) and the Asian wild strawberries (2x) were attempted. The interspecific hybrids originated from pollination of F. nilgerrensis or F. iinumae to F. xananassa cv. `Toyonoka' were all sterile pentaploids. By in vitro colchicine treatment of these sterile hybrids for chromosome doubling, many fruiting interspecific hybrids were produced. In particular, some superior hybrids were obtained from `Toyonoka' × F. nilgerrensis. From the results of RAPD analysis, the interspecific hybrids had the fragments specific for both parents. While their morphological characters were close to `Toyonoka', they had some characters from F. nilgerrensis, such as numerous hair on their petioles and peduncles. Their fruits have good characters that are same level of cultivated strawberry about size, Brix, acidity, and vitamin C content. The flesh is soft and skin color is pale pink. The aroma components are resemble F. nilgerrensis, and enrich ethyl acetate. The fragrance of interspecific hybrid like peach is characteristic.

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S.M. Silva and R.M. Beaudry

The generation of dilute vapor phase standards using the static headspace method can be challenging, requiring the construction of specialized chambers or use special methods for adding minute amounts of the compound of interest. The vapor concentration above a dilute water solution can be effective and accurate and has been used to create standards to measure the concentration for a wide range of volatile and semivolatile organic compounds. Such systems are highly temperature-sensitive, however. The goal of this work is to mathematically describe the relationship between vapor concentration above a dilute water mixture for compounds important to postharvest physiology, such as ethanol, acetaldehyde, ethyl acetate, and hexanol. The experiments were carried out in the range of 0 to 40°C and concentration of 0 to 1000 ppm for each compound. Three replications were used for each data point. The concentration was measured after thermal and chemical equilibration by gas chromatography containing a HAYESSEP-N column, by injecting 1 cc of the vapor headspace, using a 8-cm-long needle Hamilton syringe. Relationships for each of the compounds noted were successfully described employing multiple-order equations. For example, the relationship for ethanol vapor concentration was: Y = 12.12356 + 0.9461594*X + 0.5761110e-01*X2 + 0.6565694E-03*X3 + 0.23499598E-04*X4 (R 2 = 1.000), with X being the temperature in °C. The relationships described for those compounds provides an useful tool that allows us to dilute liquid standards across a range of temperatures.

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Yong Seo Park, Clara Pelayo, Betty Hess-Pierce, and Adel A. Kader

`Shinko' and `Shinsui' Asian pears were kept in air, 2 kPa O2, 2 kPa O2 + 2.5 kPa CO2, and 2 kPa O2 + 5 kPa CO2 (balance N2 in each treatment) at 0 °C or 5 °C for up to 24 weeks. The three CA treatments reduced respiration (O2 consumption) and ethylene production rates relative to air control pears; these rates were higher at 5 °C than at 0 °C and higher for `Shinsui' than for `Shinko' pears. While `Shinsui' pears had a climacteric pattern of respiration and ethylene production rates, `Shinko' pears produced very small quantities of ethylene and exhibited a non-climacteric respiratory pattern. `Shinko' pears had a much longer postharvest life than `Shinsui' pears (24 weeks vs. 12 weeks at 0 °C). CA treatments had a greater effect on delaying deterioration of `Shinsui' than `Shinko' pears, which were more sensitive to CO2 injury and associated accumulation of fermentative metabolites (acetaldehyde, ethanol, ethyl acetate). `Shinko' pears did not benefit from CA storage and were best kept in air at 0 °C. An atmosphere of 2 kPa O2 with or without up to 5 kPa CO2 delayed flesh breakdown of `Shinsui' pears during storage 0 °C.

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Hae Keun Yun, Kyo Sun Park, Jeong Ho Rho, and Hyeon Mo Jo

Breeding of cultivars resistant to anthracnose is one of the most important grape-breeding goals in Korea. Culture filtrates produced by E. ampelina were used to determine varietal susceptibility to anthracnose in grape cultivars as a substitute for pathogen inoculation or field screening in this study. Resistance evaluated by bioassay of grape leaves with culture filtrates and their ethyl acetate extracts was compared with ones from pathogen inoculation and field screening. To evaluate the resistance to anthracnose disease in grape germplasm, European grapes, American grapes, and Vitis hybrids were tested. Bioassay with culture filtrates produced by the pathogen showed that `Black Eye', `Mario', `Niunai', `Rizamat', and `Rosario Bianco' were sensitive; and `Campbell Early', `Niagara', and `Honey Red' were tolerant to anthracnose. In the result of anthracnose resistance evaluation by pathogen inoculation, some cultivars, such as `Black Swan','Rizamat', `Rosario Bianco', and `Kaiji', were susceptible; and others, such as `Campbell Early', `Niagara', `Sheridan', and `Izumo Queen', were found to be resistant to anthracnose. Evaluation in the vineyard showed that `Black Eye', `Mario', `Niunai', `Rizamat', and `Rosario Bianco' were susceptible; `Campbell Early', `Niagara', and `Honey Red' were resistant. The results of bioassay with culture filtrates of the pathogen were consistent with ones from the results by pathogen inoculation and screening in the vineyard.

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Dangyang Ke, Lili Zhou, and Adel A. Kader

`Chandler' strawberries (Fragaria ananassa Duck.) were kept in air, 0.25% O2, 21% O2 + 50% CO2, or 0.25 O2 + 50% CO2 (balance N2) at 5C for 1 to 7 days to study the effects of controlled atmospheres (CAs) on volatiles and fermentation enzymes. Concentrations of acetaldehyde, ethanol, ethyl acetate, and ethyl butyrate were greatly increased, while concentrations of isopropyl acetate, propyl acetate, and butyl acetate were reduced by the three CA treatments compared to those of air-control fruit. The CA treatments enhanced activities of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) but slightly decreased activity of alcohol acetyltransferase (AAT). The results indicate that the enhanced PDC and ADH activities by CA treatments cause ethanol accumulation, which in turn drives the biosynthesis of ethyl esters. The increased ethanol concentration also competes with other alcohols for carboxyl groups for esterification reactions. The reduced AAT activity and limited availability of carboxyl groups due to ethanol competition decrease production of other acetate esters.