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Theodore J.K. Radovich, Matthew D. Kleinhenz, John G. Streeter, A. Raymond Miller, and Joseph C. Scheerens

Glucosinolates are secondary plant metabolites derived from amino acids and they influence human health, pest populations and crop flavor. Our primary objective was to determine the independent and interactive effects of planting date (PD) and cultivar (C) on total glucosinolate concentrations in cabbage, in part to help develop management systems that optimize them. A second objective was to explore the reported link between total glucosinolate concentrations and pungency in fresh cabbage. Six commercial fresh market cabbage cultivars were planted in May and June 2001 and 2002 at the Ohio Agricultural Research and Development Center (OARDC) Vegetable Crops Research Branch in Fremont, Ohio. Total glucosinolate concentrations in horticulturally mature heads were determined using a glucose evolution procedure. In 2001, 12 to 14 experienced panelists also scored sample pungency. Total glucosinolate concentrations were significantly affected by PD and C, but the PD × C interaction was not significant. Mean glucosinolate concentrations were greater in Maythan June-planted cabbage in both years. Cultivar ranking with regard to glucosinolate concentrations was similar between planting dates in both years. `Cheers' had the highest mean glucosinolate concentrations (23.1 and 29.5 mmol·kg-1 dry weight in 2001 and 2002, respectively) and `Solid Blue 790' the lowest (17.1 and 19.7 mmol·kg-1 dry weight in 2001 and 2002, respectively). In 2001, panelists generally scored cultivars highest in glucosinolates as more pungent than cultivars lowest in glucosinolates. These data suggest that planting date and cultivar effects on total glucosinolate concentrations in cabbage are largely independent. Climatic data suggest that higher air temperatures during head development of May-compared to June-planted cabbage induced plant stress and resulted in higher glucosinolate concentrations in May-planted cabbage.

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E.A. Baldwin, T.M.M. Malundo, R. Bender, and J.K. Brecht

Mango fruit, cv. Tommy Atkins, were harvested from two grove sites in south Florida at mature green (MG) and tree ripe (TR) maturities. The fruit were either coated with one of two coatings (NS = Nature Seal® 4000, a polysaccharide coating, or CW = carnauba wax) or left uncoated (control) and stored in humidified air or held in a controlled atmosphere (CA = 5% O2 plus 25% CO2) at 12 °C for 21 days followed by 2 days in air at 20 °C. There were 12 fruit for each treatment/maturity stage combination replicated by grove site. After storage, the pulp was homogenized for later consumer or descriptive panel analysis. Measurements for total soluble solids (SS), pH, titratable acidity (TA), and flavor volatile compounds were also made. TR-harvested fruit were sweeter and generally more aromatic than MG-fruit as determined by sensory and/or chemical analysis. NS-coated fruit were more sour, bitter, and astringent compared to controls and CA-treated fruit. NS-coated fruit received lower overall consumer scores than CW-coated fruit, but were not different from controls or CA-treated fruit. This was reflected also in descriptive panel ratings. There were no differences based on storage treatment for SS, pH, or TA; however, NS-coated fruit were higher in acetaldehyde, methanol and ethanol compared to control or CA-treated fruit. Correlation and regression analysis showed significant relationships between sensory and chemical data.

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Elizabeth A. Baldwin and Bruce Wood

Unsaturated fatty acid oxidation results in rancid off-flavors in pecan [Carya illinoinensis(Wangenh.) K. Koch] kernels, which shortens shelf life under ambient conditions. For this reason kernels are stored under costly refrigeration. Edible coatings [hydroxypropyl cellulose (HPC) and carboxymethyl cellulose (CMC), plus various additives] were used to restrict oxygen contact with kernel associated fats by acting as a barrier to gas exchange. Fresh pecans were acquired from orchards, air-dried, shelled, and treated with various coating formulations. The kernels were then drained, dried, and stored several months in open air or perforated zip-lock plastic bags at 20 to 25 °C and periodically evaluated by 18 to 20 sensory panelists using a 9-point hedonic scale for appearance, shine, off-flavor or overall flavor, and texture. Coated kernels generally scored lower for off-flavor, and higher for overall flavor. Preliminary coatings resulted in a less preferred appearance, but modifications to formulations of subsequent coatings resulted in either improved appearance or had no effect on appearance of kernels compared with uncoated control. Coatings with CMC imparted a shine to coated kernels, but did not generally affect texture. Hexanal accumulation, a good indicator of rancidity, of the homogenate of kernels stored at ambient temperatures for 5 and 9 months was lower in kernels coated with CMC than in the uncoated control, with CMC coatings including α-tocopherol being most effective. Thus, CMC-based coatings exhibit potential for extending the shelf life of pecan kernels.

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Andrew R. Jamieson, Kevin R. Sanderson, and Roger J.A. Tremblay

., Nova Scotia, Canada, in Spring 1992 and ‘Laurel’ was selected for its sweetness and aromatic strawberry flavor in 1993 by A.R. Jamieson. ‘Laurel’ was tested as selection K93-20. Performance ‘Laurel’ has fruited at Kentville each year since 1995 in at

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Adriana Contreras-Oliva, Cristina Rojas-Argudo, and María B. Pérez-Gago

replicates of 10 fruit each was used to determine these parameters. Sensory analysis. Sensory evaluation was conducted by 10 trained judges. Panelists rated flavor on a 9-point scale, in which 1 to 3 represented a range of non-acceptable quality with

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Andrew R. Jamieson

yields ( Table 1 ). The seasonal mean berry weight of ‘AAC Lila’ is similar to ‘Wendy’ and ‘Brunswick’ ( Table 1 ). Fruit Description The flavor of ‘AAC Lila’ is frequently described as clean and fresh, a pleasing combination of sweetness and acidity

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J. Song and R.M. Beaudry

Aroma analysis of horticultural produce is an emerging field in which both flavor producing and malodorous compounds are detected from within a complex sample matrix. Qualitative and quantitative information is desired to monitor produce ripeness and provide quality control over processed products such as juices, preserves and canned products. Conventional analysis methods such as purge and trap and gas chromatography–mass spectrometry provide much of this information but are laborious and time consuming. Faster techniques are required when large numbers of samples are being analyzed and when rapid feedback to the produce harvester is required. Solid-phase microextraction (SPME) has recently been shown to significantly reduce the sampling times required by more conventional methods. The use of fast gas chromatographic techniques along with the recently commercialized time-of-flight mass spectrometer has also significantly reduced the separation and analysis times. We have combined SPME with gas chromatography–time-of-flight mass spectrometry as a rapid and quantitative tool for the analysis of flavor volatiles in apples and tomatoes. The sampling and analysis processes provide significant improvements to sample throughput, with analysis times taking only 2–6 minutes. The linear response of this system to butylacetate, ethyl-2-methylbutanoate and hexylacetate ranges from ppb to ppm levels, and the identification of unknown flavor compounds is possible even in the presence of other co-eluting compounds. The SPME technique is able to investigate volatiles changes in apple cuticle and tissues, which open the new possibility for flavor biochemistry research.

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Roy E. McDonald, Lawrence A. Risse, and Charles R. Barmore

Chopped `Salinas' crisphead lettuce (Lactuca sativa L.) was packaged in four types of polymeric films and stored at 1 or 5C for 14 days. Discoloration and off-flavors developed in lettuce stored in the two films in which the naturally produced CO2 rose above 20%. In the two films (oriented low-density polyethylene) with O2 transmission rates higher than 3000 ml·m-2· day-1·atm-1 at 22C, CO2 remained below 20%, O2 was between ≈ 2% and 15%, and the lettuce was acceptable after 14 days of storage at either 1 or 5C. Appearance and flavor were affected more by temperature than by length of storage.

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M.A. Cliff, M.C. King, and C. Hampson

Conventional (analysis of variance, mean preference scores) and novel (R-index) methodologies for hedonic assessments of `Silken' and `Creston' apple (Malus ×domestica Borkh.) cultivars from the breeding program at Summerland, B.C., were compared with the standard cultivars Royal Gala, Jonagold, and Golden Delicious. Visual and flavor preferences were evaluated for either three or five cultivars by panels of 50 to 200 consumers. Consumers were successfully able to evaluate five apple samples at a given session. Significant differences in mean preference scores and R-indices were found among cultivars. Both `Silken' and `Creston' had higher flavor and lower visual preference ratings than did `Royal Gala'. Results were consistent for both methodologies when panels consisted of 100 or more consumers. R-index, however, expressed the results as a probability rather than a mean score, and was a more understandable and interpretable measure of consumer preference than were preference ratings.

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David E. Kopsell, William M. Randle, and Norman E. Schmidt

The lachrymatory factor [LF, (Z,E) propanethial S-oxide] is a direct product of 1-propenyl cysteine sulfoxide (1-PRENCSO) hydrolysis and dominates onion flavor when present in high concentrations. To evaluate LF as a potential means of assessing flavor quality, two onion cultivars were greenhouse-grown and the bulbs stored for 4 months at 3 ± 1 °C, 70% relative humidity. Onions were evaluated at monthly storage intervals for LF development in bulb macerates following a 120 seconds incubation time. When LF was compared to amounts of 1-PRENCSO hydrolysis, we found that LF was severely underestimated. The relationship of LF and 1-PRENCSO also varied between cultivars during storage. As `Granex 33' was stored for longer periods, the amount of LF measured at 120 seconds more closely reflected the amount of 1-PRENCSO hydrolyzed. LF from `Dehydrator #3', however, was consistently underestimated regardless of storage time. Therefore, a second experiment was conducted using individual bulbs of two onion cultivars in an attempt to determine the optimal incubation time for LF quantification. Maximum LF among bulbs was generally detected 5-10 seconds after tissue maceration for `Dehydrator' and after 15-30 seconds for `Sweet Vidalia'. The amount of LF quantified between 5 and 120 seconds decreased linearly for nine of ten bulbs of `Dehydrator', but this trend was less apparent for `Sweet Vidalia'. A uniform LF incubation time for individual bulbs, therefore, may not be possible for all cultivars. These data show a complex relationship among and within onion cultivars for 1-PRENCSO hydrolysis and the formation of LF in onion macerates.