The effects of temperature and developmental age on flavor intensity and quality were tested by growing `Granex 33' onions (Allium cepa L.) at 16.5, 22.1, 26.7, and 32.2 (±0.4) °C for 50 days and to maturity. Plants were harvested and evaluated for growth characteristics. Bulbs were then analyzed for sulfur (S) assimilation and flavor development parameters. Total bulb S increased linearly with temperature regardless of bulb age. Bulb sulfate changed little over temperatures, indicating that organically bound S increased with temperature. Total pyruvic acid content (pungency), total S-alkenyl cysteine sulfoxide (ACSO) content and individual ACSOs increased linearly in response to temperature when measured at the two developmental stages. Though trans-(+)-S-(1-propenyl)-L-cysteine sulfoxide was the predominant ACSO at most temperatures, (+)-S-methyl-L-cysteine sulfoxide accumulation was greatest among the individual ACSOs in mature bulbs grown at 32.2 °C. Additionally, (+)-S-propyl cysteine sulfoxide was present in the least amount at all treatment levels and developmental stages. Gamma glutamyl propenyl cysteine sulfoxide and 2-carboxypropyl glutathione peptides in the flavor biosynthetic pathway also increased linearly with temperature. When ACSOs were assessed in onion macerate as a measure of alliinase activity, levels of degraded ACSOs increased linearly with growing temperature. The relative percentage of most ACSOs hydrolyzed, however, did not change in response to growing temperature. This suggested that the activity of alliinase was proportional to the amounts of flavor precursors synthesized. Growing temperature, therefore, should be considered when evaluating and interpreting yearly and regional variability in onion flavor.
Timothy W. Coolong and William M. Randle
Solveig J. Hanson and Irwin L. Goldman
.S. Department of Agriculture, 2017 ) with both standard red table beets and lesser volumes of novel cultivars ( Goldman and Navazio, 2003 ). Flavor is critical to consumer acceptance of horticultural crops, so while different table beet flavor profiles may be
Bruno Defilippi*, Abhaya Dandekar and Adel Kader
To understand the role of ethylene in overall flavor of apple fruits, ethylene production, and action were reduced using apple trees lines transformed for suppressing activity of ACC-synthase or ACC-oxidase enzymes, and 1-methylcyclopropene (1-MCP), an ethylene action inhibitor. A major reduction in ethylene biosynthesis and respiration rates was measured in fruits from these treatments. As expected, we found differential levels of dependence of flavor components on ethylene biosynthesis and action. Regarding aroma production, an ethyleneassociated event, headspace analysis showed a reduction in ester production in the ethylene-suppressed lines and in the apples treated with 1.0 μL·L-1 1-MCP for 20 hours at 20 °C. However, no major differences were observed in concentrations of alcohol and aldehyde volatiles. Other flavor metabolites that showed an ethylene-dependent pattern were organic acids and sugars. Malic acid degradation was significantly reduced under ethylene suppressed conditions, showing a recovery after exposing the fruit to ethylene. Sucrose and fructose concentrations were influenced by suppression or enhancement of ethylene. Total phenolics and individual phenolics showed an ethylene-dependent behavior only when ethylene biosynthesis was reduced, but not when ethylene action was affected. These results suggest that the regulatory mechanisms of aroma biosynthesis in apple are under partial ethylene regulation. Therefore, we are using the ethylene suppressed apple fruits study the channeling and regulation of other metabolic pathways that lead to the manifestation of a complex trait like fruit quality.
William M. Randle
Twenty bulbs from each of 10 onion (AIlium cepa L.) cultivars and one mass population were harvested from two locations and evaluated for three traits associated with flavor quality. Variance components for soluble solids content (SSC), pyruvic acid concentration (PAC), and percent S were calculated, and sampling schemes required to detect specific differences among treatment means were determined. In general, a five-bulb sample and four replications were sufficient to detect desired differences for SSC and PAC, whereas percent S required a larger sample size and more replications.
Eliahou Cohen, Yavin Shalom and Ida Rosenberger
Britex and Zivdar, water-based polyethylene waxes, were applied in commercial and experimental formulations as spray coating, a single dip, or double dips on `Murcott' tangerine (Citrus reticulate Blanco) fruits. Postharvest waxing of `Murcott' tangerine reduced weight loss but affected the sensory characteristics of the fruit. Charges in fruit weight loss and juice composition occurred in the waxed fruits after 4 weeks of storage at 5C plus 1 week of simulated retail handling at 17C. Changes in internal fruit atmosphere were related to fruit flavor quality.
John W. Scott
all the data that might be desired. Some traits are fairly straightforward to measure, whereas others are not so amenable to standardized phenotyping. Flavor is an important trait that fits the latter category. Consumers have found considerable
Leonard M. Pike
`BetaSweet' is a new “designer” carrot that was conceived as a research project with the objective to create a new high-quality vegetable with unique characteristics. The gene responsible for purple or maroon color in carrots is a natural one and has been around for many years. Carrot breeders have discarded carrots which occasionally segregated to this color because orange has been the preferred traditional color. In 1989, three carrots grown from Brazilian seed were observed to have a blotchy maroon color mixed with the normal orange. Within two generations of breeding effort I had obtained a few carrot roots with near complete maroon exterior color and orange interior. The contrast of orange and maroon was very attractive in carrots cut as coins or sticks. The maroon and orange color would serve as the perfect way to identify and promote this new variety. Several additional generations were required using extensive laboratory testing for low terpenoids (strong carrot flavors), high sugars, high carotene, and crispy texture. Thousands of carrot roots were analyzed and selected for those qualities and for the dark maroon exterior and orange interior colors. The few best for those characteristics were intercrossed, and reselected for their adaptation when grown under Texas climatic conditions.
Bhimanagouda S. Patil and Bill B. Dean
Fall onions, grown for their long shelf life, have become popular both in domestic and export market. Sixty cultivars of onion from 14 major seed companies were grown in Quincy, Wash., and were analyzed for their flavor, quality, and anticarcinogenic flavonol, quercetin. The highest quercetin concentration (in mg·kg–1 fresh weight) was observed in the red onion `Feugo' (495.6) followed by `Tango' (396.8), while the least amount was in the yellow onion `Pinnacle'(152.5). The pyruvic acid content varied from 1.5 to 18.7 mmol·g–1 and total sugar (glucose, fructose, and sucrose) levels ranged from 9.4 to 36.9 mg·g–1 fresh weight among different cultivars. The ratio of sugar:pyruvic acid showed marked variation (1.6 to 64.00) among different cultivars. The variation in oligosacharides were ≈60-fold over all cultivars. The maximum degree of polymerization (DP) observed was DP8. We conclude that there is a potential for developing a mild onion for longer shelf life and better health properties. Yield at harvest and storage performance based on rot also was evaluated during storage.
Mark K. Ehlenfeldt
‘Razz’ is a midseason-ripening, tetraploid, highbush blueberry ( Vaccinium corymbosum L.) with unique raspberry flavor overtones that has been released by the cooperative breeding program of the Agricultural Research Service of the U.S. Department
Jinhe Bai, Elizabeth Baldwin, Jack Hearn, Randy Driggers and Ed Stover
contents in FF-1-74-14 and FF-1-64-97 were similar to or higher than that of ‘Hamlin’, whereas all other hybrids had somewhat lower limonene content ( Table 2 ). Limonene has been suggested to be one of the most important contributors to orange flavor