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Eduardo D. Munaiz and Michael J. Havey

damaging wavelengths of light ( Holmes and Keiller, 2002 ). Wax composition varies among plants ( Bernard and Joubès, 2013 ; Jenks et al., 1995 ), and in arabidopsis ( Arabidopsis thaliana ), the predominant waxes are C29 alkanes, ketones, and secondary

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Steven J. Damon and Michael J. Havey

insects respond to cues from the chemistry of the waxes, and the broad diversity of compounds found in epicuticular waxes (long-chain fatty acids, esters, ketones, alkanes, and alcohols) may help insects to identify their host plants ( Blaney and Chapman

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Eduardo D. Munaiz, Russell L. Groves and Michael J. Havey

Onion thrips (Thrips tabaci) is the main insect pest of onion (Allium cepa), and feeding damage routinely causes serious yield losses. Lower amounts of epicuticular waxes on onion leaves have been associated with fewer onion thrips and less feeding damage, and research is needed to assess the relationships between amounts and composition of epicuticular waxes and feeding damage by onion thrips. This study used gas chromatography mass spectroscopy to determine amounts and types of epicuticular waxes on the foliage of onion accessions that had been field-selected for lower damage from onion thrips. Hentriacontanone-16 (H16), octaconasol-1, and triacontanol-1 were the most prevalent waxes on the foliage of these selections. Amounts of H16 were significantly lower on selections visually classified as having glossy or semiglossy foliage. Semiglossy selections were identified with similar amounts of total epicuticular wax as waxy phenotypes, due primarily to lower amounts of H16 and higher amounts of other waxes. These semiglossy selections suffered significantly less feeding damage from onion thrips in a field evaluation, supporting the identification of unique wax profiles toward the development of thrips-resistant onion.

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Jian-rong Feng, Wan-peng Xi, Wen-hui Li, Hai-nan Liu, Xiao-fang Liu and Xiao-yan Lu

identified from these studied cultivars, including 80 esters, 25 aldehydes, 39 alcohols, 21 ketones, 27 olefins, 1 acid (data not shown), and 15 other trace compounds ( Table 3 ). The result had compared with previous report ( Zhang et al., 2008 ) that 107

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Steven J. Damon, Russell L. Groves and Michael J. Havey

been identified in plant epicuticular waxes, including alkanes and ketones of odd chain length and esters, fatty alcohols, and fatty acids of even chain length ( Eigenbrode and Espelie, 1995 ; Tulloch, 1976 ). Sorghum [ Sorghum bicolor (L.) Moench

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Chunyu Zhang, Xuesen Chen, Hongwei Song, Yinghai Liang, Chenhui Zhao and Honglian Li

( Laurens, 1999 ). In apple, volatile components are composed of esters, alcohols, aldehydes, ketones, and ethers ( Dimick and Hoskin, 1983 ; Kakiuchi et al., 1986 ). Research by Kakiuchi et al. (1986) showed that esters are the most abundant flavor

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John C. Beaulieu, Rebecca E. Stein-Chisholm and Deborah L. Boykin

-Aldrich Fine Chemicals, Flavors and Fragrances Products [St. Louis, MO]}, according to Table 1 . Compound classes were defined and comprised of aldehydes (ALD), alcohols (OLS), esters (EST), ketones (ONE), furans (FUR), terpenoids (OID), and aromatics (ARO

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Sharon Dea, Jeffrey K. Brecht, Maria Cecilia do Nascimento Nunes and Elizabeth A. Baldwin

. Slices from ripeness stage B had an intermediate concentration of acetaldehyde and hexanal compared with stages A and C, similar concentration of ethanol as A, similar content of ketones and esters as C, and lower or equal amount of the terpenes measured

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Dangyang Ke and Michael Boersig

Consumer acceptance of sensory quality was significantly correlated (P = 0.05) with overall eating quality of tomatoes (Lycopersicon esculentum Mill.) determined by a trained taste panel. The overall eating quality was partitioned into three flavor components (sweetness, sourness, and aroma) and internal texture. Relationships between the sensory flavor components and concentrations of several chemical compounds were analyzed in tomatoes of eleven varieties within a range of acceptable texture. Sweetness was significantly correlated with total sugar concentration and overall flavor at P = 0.01 and 0.001. High concentrations of two ketone volatiles (6-methyl-5-hepten-2-one and 1-penten-3-one) were significantly correlated with aroma and overall flavor at P = 0.05 to 0.001. This study indicates that positive tomato flavor may be characterized by high sweetness, moderate acidity, and high concentrations of certain ketone volatiles.

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Charles F. Forney

Volatile compounds are responsible for the aroma and contribute to the flavor of fresh strawberries (Fragari×anannassa), red raspberries (Rubus idaeus), and blueberries (Vaccinium sp.). Strawberry aroma is composed predominately of esters, although alcohols, ketones, and aldehydes are also present in smaller quantities. The aroma of raspberries is composed of a mixture of ketones and terpenes. In highbush blueberry (Vaccinium corymbosum), aroma is dominated by aromatic hydrocarbons, esters, terpenes and long chain alcohols, while in lowbush blueberries (Vaccinium angustifolium), aroma is predominated by esters and alcohols. The composition and concentration of these aroma compounds are affected by cultivar, fruit maturity, and storage conditions. Volatile composition varies significantly both quantitatively and qualitatively among different cultivars of small fruit. As fruit ripen, the concentration of aroma volatiles rapidly increases closely following pigment formation. In storage, volatile concentrations continue to increase but composition depends on temperature and atmosphere composition. Many opportunities exist to improve the aroma volatile composition and the resulting flavor of small fruit reaching the consumer.