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Céline Jouquand, Craig Chandler, Anne Plotto and Kevin Goodner

California strawberries was related to higher sugar and volatile contents. The influence of volatile compounds on the flavor quality of the strawberry was widely studied, and among the hundreds of volatiles identified in fresh strawberry, only a small portion

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Anne Plotto, Elizabeth Baldwin, Jinhe Bai, John Manthey, Smita Raithore, Sophie Deterre, Wei Zhao, Cecilia do Nascimento Nunes, Philip A. Stansly and James A. Tansey

) resulted in juice that was less sweet, more sour, more bitter, and had an off flavor described as metallic, umami (savory), salty, fermented, green, and stale ( P lotto et al., 2010 , 2011 ). Juice from symptomatic oranges generally had lower sugars

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Jinhe Bai, Elizabeth Baldwin, Jack Hearn, Randy Driggers and Ed Stover

For orange juice (OJ) use, although sugars and acids are essential for good taste, it is the volatiles that in fact determine the unique flavor of a cultivar ( Shaw, 1991 ). The hybrids between mandarin and sweet orange and their descendants

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William M. Randle

World-wide, onions are the most important member of the vegetable Alliums. Members of this group are primarily consumed because of their unique flavors and aromas. Allium aroma is dominated by organosulfur compounds arising from the enzymatic decomposition of S-alk(en)yl-L-cysteine S oxide (ACSO) flavor precursors following tissue disruption. Primary products from the decomposition of the four ACSOs are sulfenic acids, including the lachrymator, pyruvate, and ammonia. The sulfenic acids, however, are short-lived and disassociate rapidly into thiosulfinates, which, in turn, are unstable and randomly rearrange or dissociate over time. The thiosulfinates each have unique sensory qualities and are responsible for the flavor notes of fresh cut Alliums, while of the degradation compounds can contribute to off-fl avors and bitterness. ACSO concentration affects ultimate flavor and aroma intensity, while ACSO composition determines among species flavor differences. Controlling sulfur uptake and sulfur metabolism that terminates in ACSO synthesis is one method of controlling ultimate flavor and aroma intensity. Cultivar difference in the ability to absorb and metabolize sulfur have been identified. Sulfur availability, plant growing temperatures, and irrigation intensity also influence sulfur absorption and metabolism, and can be manipulated. Differences in alliinase concentration and the efficiency at which alliinase decompose the ACSO substrates also affect aroma generation. Difficulties, however, exist in controlling alliinase activity. Alliinase has been cloned and anti-sense constructs have been made, but an efficient vectoring system has yet to be developed for the Alliums.

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Barbara J. Daniels-Lake, Robert K. Prange, Sonia O. Gaul, Kenneth B. McRae, Roberto de Antueno and David McLachlan

In 2001, several million kilograms of fresh and processed potato products from the Annapolis Valley of Nova Scotia, Canada (i.e., most of the local crop) was rejected by consumers because of a strong “musty” “off” flavor and odor (OFO). As a

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T.M.M. Malundo, R.L. Shewfelt, G.O. Ware and E.A. Baldwin

Information on important flavor components for fruit and vegetables is lacking and would be useful for breeders and molecular biologists. Effects of sugar and acid levels on mango (Mangifera indica L.) flavor perception were analyzed. Twelve treatments, identified using a constrained simplex lattice mixture design, were formulated by adding sugar (60%), citric acid (40%), and water to an equal volume of mango homogenate. Using 150-mm nonstructured line scales, a trained panel evaluated the treatments according to 11 flavor descriptors. Titratable acidity (TA), pH, and total soluble solids (TSS) were also determined. Acid concentration affected ratings for sweet, sour, peachy, pine/terpentine, astringent, and biting. Except for sour taste, all descriptors were affected by sugar content while increasing water increased intensities of all flavor notes. TA, pH, and TSS/TA correlated (P < 0.01) with and were useful predictors (r > 0.80) of sour taste and chemical feeling descriptors astringent and biting. TSS, however, was not a particularly good indicator of sweetness (r = 0.72) or any other descriptor except possibly peachy (r = 0.79). It is evident from this study that sugars and acids enhance human perception of specific flavor notes in mango, including aromatics.

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Esteban A. Herrera

`Western Schley' pecans [Carya illinoinensis (Wangenh.) K. Koch] were evaluated for flavor by a 17-person sensory panel after oven-drying nuts that had been harvested 1 to 7 weeks before normal harvest in 1985. The nuts were 1) not dried, 2) oven-dried 24 hours at 29C, 3) oven-dried 24 hours at 35C, 4) oven-dried 30 hours at 29C, 5) oven-dried 30 hours at 35C, 6) dried at room temperature for 72 hours, and 7) collected at normal harvest time (control). At the start of the experiment, kernel moisture was ≈ 14%. Some of the treatments reduced kernel moisture to <5 % the first week of the experiment, but drying nuts at room temperature for 72 hours reduced kernel moisture as effectively as other treatments. Judging by kernel flavor, pecans can be harvested ≈ 4 weeks before normal harvest (performed after the first freeze in Las Cruces, N.M.) and artificially dried without affecting flavor.

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E.A. Baldwin, J.W. Scott, M.A. Einstein, T.M.M. Malundo, B.T. Carr, R.L. Shewfelt and K.S. Tandon

The major components of flavor in tomato (Lycopersicon esculentum Mill.) and other fruit are thought to be sugars, acids, and flavor volatiles. Tomato overall acceptability, tomato-like flavor, sweetness, and sourness for six to nine tomato cultivars were analyzed by experienced panels using a nine-point scale and by trained descriptive analysis panels using a 15-cm line scale for sweetness, sourness, three to five aroma and three to seven taste descriptors in three seasons. Relationships between sensory data and instrumental analyses, including flavor volatiles, soluble solids (SS), individual sugars converted to sucrose equivalents (SE), titratable acidity (TA), pH, SS/TA, and SE/TA, were established using correlation and multiple linear regression. For instrumental data, SS/TA, SE/TA, TA, and cis-3-hexenol correlated with overall acceptability (P = 0.05); SE, SE/TA (P≤0.03), geranylacetone, 2+3-methylbutanol and 6-methyl-5-hepten-2-one (P = 0.11) with tomato-like flavor; SE, pH, cis-3-hexenal, trans-2-hexenal, hexanal, cis-3-hexenol, geranylacetone, 2+3-methylbutanol, trans-2 heptenal, 6-methyl-5-hepten-2-one, and 1-nitro-2-phenylethane (P≤0.11) with sweetness; and SS, pH, acetaldehyde, aceton, 2-isobutylthiazole, geranlyacetone, β-ionone, ethanol, hexanal and cis-3-hexenal with sourness (P≤0.15) for experienced or trained panel data. Measurements for SS/TA correlated with overall taste (P=0.09) and SS with astringency, bitter aftertaste, and saltiness (P≤0.07) for trained panel data. In addition to the above mentioned flavor volatiles, methanol and 1-penten-3-one significantly affected sensory responses (P = 0.13) for certain aroma descriptors. Levels of aroma compounds affected perception of sweetness and sourness and measurements of SS showed a closer relationship to sourness, astringency, and bitterness than to sweetness.

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Stanley J. Kays and Yan Wang

Using the sweetpotato as a model, we identified precursors of critical flavor volatiles by fractionating, based upon solubility, raw roots into major groups of constituents. Volatile thermophyllic products from the individual fractions were analyized and compared to those from non-extracted root material. Volatile components were seperated and identified using GC-MS and quantified using internal standard methodology. Mechanisms of synthesis of flavor volatiles via thermophyllic reactions will be discussed, as will postharvest treatments that can modulate eventual aromatic properties of cooked plant products.

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Chengyan Yue, R. Karina Gallardo, James J. Luby, Alicia L. Rihn, James R. McFerson, Vicki McCracken, Tom Gradziel, Ksenija Gasic, Gregory L. Reighard, John Clark and Amy Iezzoni

supply, inconsistent quality, and fruit handling problems ( Brunke and Chang, 2012 ). Consumers of fresh peaches are often frustrated with inconsistent flavor and textural quality, flesh browning, and insipid taste ( Brunke and Chang, 2012 ). To enhance