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Tyler J. Simons, Christopher J. McNeil, Aubrey D. Pham, Carolyn M. Slupsky, Mikeal L. Roose and Jean-Xavier Guinard

in regard to fruit quality ( Roose, 2014 ), and the choice of rootstock involves chemical, flavor, and liking effects ( Benjamin et al., 2013 ). The ‘DaisySL’ mandarin is known for its low seed count, mid-to-late season ripening, medium-to-large fruit

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William M. Randle, David E. Kopsell and Dean A. Kopsell

A major decision in producing onions with mild flavor on low sulfur soils is determining when to stop applying SO4 -2 to the crop. Sulfate (SO4 -2) is necessary for good early growth, but high levels of available SO4 -2 late in the season increase bulb pungency. The objective of this research was to determine how sequentially reducing the availability of SO4 -2 during onion growth and development would affect flavor intensity and quality of Granex-type onions. Starting 77 days before harvest, SO4 -2 concentrations were lowered from 1 mm to 0.05 mm on different blocks of onions in a greenhouse experiment at bi-weekly intervals. Total leaf and bulb S were measured at harvest to monitor S accumulation as SO4 -2 fertility was sequentially reduced. Bulbs were harvested and analyzed for flavor precursors and their biosynthetic intermediates, gross flavor intensity as measured by enzymatically developed pyruvic acid (EPY), and soluble solids content. As SO4 -2 fertility reductions were delayed during the experiment, total leaf and bulb S increased linearly. In addition, bulb EPY concentrations increased linearly as SO4 -2 reduction was delayed, indicating increases in overall flavor intensity. While the total concentration of flavor precursors did not significantly change in response to lowering SO4 -2 fertility during the experiment, the concentrations of MCSO to 1-PRENCSO did. MCSO concentration decreased and then increased in a quadratic manner. MCSO produces fresh onion and cabbage like flavors. 1-PRENCSO, on the other hand, increased linearly as the high SO4 -2 fertility level was extended through bulb maturation. Increasing concentrations of 1-PRENCSO causes onions to have significantly more heat and mouth burn when eaten. Reducing available SO4 -2 49 days prior to harvest coincided with a reduction in EPY and a change in the flavor biosynthetic pathway that appeared to be associated with the metabolic changes occurring with the onset of bulbing. Chemical names used: enzymatically developed pyruvic acid (EPY); methyl cysteine sulfoxide (MCSO); 1-propenyl cysteine sulfoxide (1-PRENCSO).

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T.W. Miller, D.S. Mattinson, B.C. Bostick, E. Fallahi and J.K. Fellman

Light has long been known to stimulate anthocyanin accumulation in apple peel, but changes in apple flavor as a result of fruit shading is poorly understood. Some growers maintain that the redder the strain, the less flavorful the fruit. An experiment was conducted to help characterize the role of light in biosynthesis of color versus flavor molecules in apple peel. Bags fashioned from 3 meshes of shade cloth were fastened around fruitlets of red delicious strains `Starkrimson' and `Topred' on M26, MM106, and MM111 by 21 DAFB to produce average light ranges of 100%. 41-68%, 12-30%, and < 1% of full sun incident upon the fruit. Observations from the 1993 harvest indicate that anthocyanin content of peel increased with fruit maturity and level of sunlight. Concentrations of flavor molecules were higher with low and moderate shade than with full sun, and also increased with fruit maturity. From this harvest data, it appears that apple flavor can be enhanced by lightly shading fruit without substantially reducing fruit color.

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Anne Plotto, Mina R. McDaniel and James P. Mattheis

Aroma and flavor characters of `Gala' apples [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. `Gala'] were identified by 10 trained panelists. A vocabulary of 13 aroma descriptors and 16 flavor descriptors were used to characterize changes in controlled atmosphere (CA) and air, or regular atmosphere (RA) storage over 20 weeks. When compared with RA storage, the intensity of fruity (pear, banana, and strawberry) and floral descriptors decreased after 10 weeks in CA for whole and cut fruit aroma and flavor. During the entire storage period under CA, aroma of cut apples retained high vegetative and citrus characters but had a less intense anise aroma. Sourness and astringency were significantly higher for CA-stored apples, and sweetness was significantly lower. A musty note was perceived in whole apples stored in CA for 20 weeks. Aroma of whole fruit stored for 16 weeks in CA followed by 4 weeks in RA was higher in fruitiness, banana, floral, and anise characters when compared with apples stored 20 weeks in CA. There was no difference between fruit stored in CA followed by RA versus CA stored apples for flavor and aroma of cut fruit. Changes in descriptor ratings during storage are discussed in relation to gas chromatography and olfactometry data obtained with the Osme method.

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J.C. Beaulieu, J.A. Miller, D.A. Ingram and K.L. Bett

Much fresh-cut apple research has focused on browning, yet little sensory and flavor analysis has been performed. We therefore evaluated postharvest and flavor changes in stored fresh-cut `Gala' apples prepared after harvest or after CA storage (3 months, 1.4% CO2 and 3% O2). Apples were washed, cored, sliced, dipped in browning inhibitors (BI; Na-erythorbate + CaCl2), packaged in LLDPE bags, and evaluated for descriptive flavor attributes, GC volatiles, firmness, CO2 and O2 and color after 0, 2, 7, and 14 days at 1 °C. Initial apple firmness pre-CA vs. post-CA was 38.3N and 32.7N. Bag O2 concentration dropped to 1% to 2% by day 14 and day 7 for pre- vs. post-CA, respectively. CO2 concentration in bags increased linearly through day 14 in both pre- and post-CA. All pre-CA Hunter L values were higher than post-CA for all treatments on all sampling days. Both BI treatments maintained color for 14 days, but freshly cut (FC) wedges were generally superior whereas stored untreated fresh-cut (SFC) wedges browned markedly by day 2. There was no apparent difference between BI levels in terms of browning or flavor. BI-treated wedges were rated more astringent than FC and SFC, especially after CA. With few exceptions, “fruity”, “raw/ripe apple,” and “sweet” attributes were higher in all pre- vs. post-CA treatments. This trend was conserved through 14 days of storage per treatment. “Sour” and “citrus” scores were higher after CA only in BI-treated wedges. Major compounds recovered were butanol, butyl acetate, hexanol, 2-methylbutyl acetate, amyl/isoamyl acetate, hexyl acetate, 2-hexenyl acetate, butyl 2-methylbutanoate, butyl hexanoate, hexyl butanoate, hexyl 2-methylbutanoate, hexyl hexanoate, isobutyl octanoate and α-farnesene. Flavor-related compounds varied markedly through storage and after CA. The GC volatile analysis will be presented along with any possible correlation to trained sensory evaluations.

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B. Ratanachinakorn, A. Klieber and D.H. Simons

Tomatoes (Lycopersicon esculentum Mill. `Bermuda') were vacuum infiltrated at the breaker stage with 25 to 55 mL·L-1 ethanol (EtOH) vapor at a 10 kPa pressure for 5 minutes and then held for a further period before ripening in air at 22 °C. Fruit could tolerate these EtOH vapor concentrations for no longer than 0 to 12 hours after vacuum infiltration, depending on concentration; otherwise skin pitting, uneven ripening and off-flavors resulted. Noninjurious conditions delayed ripening, as judged by color change, by an additional 1 to 5 days compared with 4 days for the control; aroma or flavor were not altered as determined by a trained taste panel, except in extreme conditions where in some cases off-flavors increased. Soluble solids and titratable acidity did not vary, but pH increased by 0.1 units in some treatments. In control fruit EtOH was found only in the gel tissue, and acetaldehyde (AA) was higher in the gel tissue compared with the pericarp and columella, indicating different metabolic behavior of the various tomato tissues. During vacuum exposure, EtOH moved through the stem scar and to a much lesser extent through the epidermis; during subsequent exposure to EtOH more EtOH moved through the epidermis than before, but still less than through the stem scar. AA increased following EtOH uptake, but all increases in EtOH and AA disappeared before fruit ripened.

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John C. Beaulieu, Karen L. Bett, Elaine T. Champagne, Daphne A. Ingram, James A. Miller and Ralph Scorza

Many consumers do not buy peaches due to the fuzzy skin and seed stone and because out-of-season peaches do not possess optimum tree-ripe flavor. The feasibility of using a non-browning freestone peach to deliver high-quality fresh-cut products was investigated. Changes in fresh-cut flavor, texture, and postharvest attributes of commercial-ripe (CR) vs. tree-ripe (TR) harvested and shipped `Bounty' peach was assessed. Fresh-cut CR wedges had an initial firmness of 20.9 N, whereas TR wedges had 11.2 N. On day 2, firmness decreased roughly 3% to 12% and 35% to 45% for CR and TR wedges held at 1 °C, respectively. By day 5, CR wedges hardened (24.5 N) whereas TR did not return to their initial firmness; increasing marginally through day 7. Sensory panel hardness for CR did not change through storage, but with TR wedges, hardness decreased through day 2 then increased until day 7. Little variation was noted in the initial soluble solids for CR vs. TR wedges (11.7, vs. 11.4 °Brix, respectively). After 7 days storage, °Brix decreased 7.5% to 12% in CR and 4.5% to 12% in TR wedges. Yellow flesh color (b*) decreased in all CR and TR treatments through storage. Flavor compounds in expressed juice were analyzed by solid phase microextraction with GC-MS. Several peaks were identified that may be associated with flavor-related changes that occurred during storage. For example, low molecular weight acetates and 6C compounds almost disappeared during storage, whereas short chain fatty acids, lactones, and palmitic acid increased markedly through storage. In TR, the “fruity” descriptor decreased throughout storage and “sweet aromatic” increased slightly (day 2) then decreased through day 7.

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Elizabeth A. Baldwin, Myrna O. Nisperos-Carriedo and Manuel G. Moshonas

Whole tomato fruit (Lycopersicon esculentum Mill.), cvs. Sunny and Solarset, were analyzed at 5 different ripening stages for ethylene and CO2 production. Homogenates from the same fruit were prepared for determination of color, flavor volatiles, sugars and organic acids. Of the flavor volatiles measured, only eugenol decreased during ripening in both varieties and 1-penten-3-one in `Sunny' tomatoes. Ethanol, and trans-2-trans-4-decadienal levels showed no change or fluctuated as the fruit matured while all other volatiles measured (cis-3-hexenol, 2-methyl-3-butanol, vinyl guiacol, acetaldehyde, cis-3-hexenal, trans-2-hexenal, hexanal, acetone, 6-methyl-5-hepten-2-one, geranylacetone and 2-isobutylthiazole) increased in concentration, peaking in the later stages of maturity. Synthesis of some volatile compounds occurred simultaneously with that of climacteric ethylene and color. `Solarset' fruit exhibited higher levels of sugars and all flavor components except ethanol, vinyl guiacol, hexanal and 2-methyl-3-butanol in the red stage. There were no differences between these varieties for acids

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Lori Hoagland, John Navazio, Jared Zystro, Ian Kaplan, Jose Gomez Vargas and Kevin Gibson

example, flavor is often cited as one of the most common reasons why consumers purchase local food ( Zepeda and Leviten-Reid, 2004 ). Traditional tomato breeding programs must select cultivars that are able to withstand mechanical injury during processing

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Gael Benoteau and Andrew G. Reynolds

The potential for interference by specific C6 compounds in the colorimetric quantitation of grape (Vitis vinifera L.) monoterpenes was investigated in model solutions and muscat and neutral-flavored grape cultivars. The unsaturated C6 aldehyde 2-hexen-1-al (2HX) showed color absorption at 608 nm in distilled water after reaction with an acidified vanillin solution. Absorbance also increased significantly when 2HX was added to a series of linalool solutions; ≈2.5 mg 2HX per liter of a 1-mg·liter–1 linalool solution increased the absorbance by >10%. Adding 2.5 mg 2HX per kilogram of `Gewürztraminer' berry homogenate significantly increased apparent free volatile terpene (FVT) concentrations to 121% of unadulterated control treatments but did not affect potentially volatile terpenes (PVT). Adding 2HX also increased apparent FVT concentration in `Perlette' and `Flame Seedless'. Both neutral-flavored table grape cultivars contained some FVT and PVT as a consequence of their muscat ancestries. FVT and PVT quantitation by colorimetric methods may be subject to significant error if the concentration of 2HX and other unsaturated C6 compounds in grape berries or must are >5 mg·liter–1. However, low concentrations of unsaturated C6 compounds (<80 μg·liter–1) in British Columbia wines suggest that there is a low probability of significant interference with this method.