Five short-day onion (Allium cepa L.) cultivars grown with high (4.0 meq S/liter) and low (0.1 meq S/liter) S fertility were evaluated for ontogenetic changes in leaf S concentration and the association between leaf S concentration and final bulb pungency as reflected by pyruvate formation. Cultivars differed in leaf S concentration at each of eight sampling dates during growth and development, but the pattern of leaf S accumulation among cultivars was similar. Leaf S concentration increased during early plant development while in a nonbulbing photoperiod, but decreased as bulbing progressed to maturity with high and low S fertility. The decline in leaf S concentration during bulbing was more severe with low than with high S fertility. Leaves that were left to dry on the mature bulb lost most of their S, especially with 0.1 meq S/liter, a result that could have implications in final bulb flavor intensity. Correlations generally were poor between leaf and final bulb S concentration or pungency.
W.M. Randle, M.L. Bussard and D.F. Warnock
Angela R. Davis and Stephen R. King
The Agricultural Research Service of the U.S. Department of Agriculture announces the release of MSW-28, a watermelon [ Citrullus lanatus var. lanatus (Thunb.) Matsum. & Nakai)] line that exhibits medium sugar content (brix) and full flavor of
N.A. Mir, J. Song and R. Beaudry
Peel discs (0.2 mm in diameter) of refrigerated, air-stored apple that were immersed in a medium isotonic with that of fruit sap were allowed to photosynthesize either in a closed or flow-through system. The photosynthetic net evolution of O2 in the light or consumption in the dark was used to predict the duration of the experiment that would be within the critical limits of aerobiosis. Using GC-MS system, volatile emissions from these tissues were determined, in the head space and liquid medium. The volatile profile generated from head space analysis was essentially similar to that of whole fruit. Light, compared to the dark treatment, stimulated the synthesis of nearly all volatiles, especially α-farnesene. The synthesis of 6-methyl-5-hepten-2-one, an oxidative product of α-farnesene that causes scald like symptoms in whole fruit, was observed only under lighted conditions. While O2 content in the medium seemed to have no effect on the volatile build-up in the head space, a C15 sesquiterpene with a mass spectrum similar to hydroperoxide breakdown products of α-farnesene was synthesized only in presence of O2 in the reaction medium. Inhibition of light reactions of photosynthesis with DCMU, suppressed the synthesis of various volatiles in the head space suggesting the role of chloroplast activity in aroma development. We suggest that peel discs work well as a model system to study flavor chemistry in apple.
R.E. McDonald, T.G. McCollum and E.A. Baldwin
The objective of this study was to determine the effects of prestorage heat treatments on chilling tolerance of tomatoes. Mature-green `Agriset' tomato fruit (Lycopersicon esculentum Mill.), either C2H4-treated or not, were immersed in 42C water for 60 min, held in 38C air for 48 hours, or not treated, and then stored at either 2C (chilled) or 13C (nonchilled) for 14 days before ripening at 20C. Heat-treated fruit stored at 2C and transferred to 20C ripened normally while nonheated fruit decayed before reaching red ripe. Color (a*/b* ratio), lycopene content, and internal quality characteristics of fruit were similar at the red-ripe stage irrespective of method of heat treatment. In red-ripe heat-treated fruit, free sterol levels were significantly higher in chilled fruit than in nonchilled fruit. Heating fruit in 38C air resulted in significantly higher levels of some free sterols compared with heating fruit in 42C water. Of the 15 flavor volatiles analyzed, six showed significantly decreased concentrations as a result of C2H4-treatment and seven showed decreased concentrations when stored at 2C before ripening. Some volatiles were decreased by the heat treatments. Prestorage short- and long-term heat treatments could allow for storage of mature-green tomatoes at lower temperatures with little loss of their ability to ripen normally.
Lei Gao, Shengjie Zhao, Xuqiang Lu, Nan He and Wenge Liu
quality, and metabolism of the fruit ( Silva et al., 2004 ; Zampini et al., 2008 ). Furthermore, organic acids have important nutritional value for the human body; the natural flavor malic acid is conducive to amino acid absorption, whereas citric acid
L.A. Gills, A.V.A. Resurreccion, W.C. Hurst, A.E. Reynolds and S.C. Phatak
Descriptive analysis was used to compare sensory color, flavor, and textural attributes of Georgia-grown carrots. The relation between °Brix, total sugar, and intensity perception of sweetness was also studied. Significant differences existed in the perception of sweet taste and of color, and in levels of °Brix and percentage of sugar among all cultivars, but perceived intensity of sweetness was not related to the levels of °Brix or percentage of sugar. No significant differences were found among cultivars in harsh carroty, green, astringent, and earthy flavors, and in the perception of sour taste. Intensity ratings for perceived hardness were nonsignificant in either study. Differences in sensory profiles existed among all cultivars, but no trend was evident in the relation of sweetness to harsh flavor.
Ricardo Goenaga, Heber Irizarry and Brian Irish
conducted at Guittard Chocolate Company, Burlingame, CA, using the protocol of the CFC/ICCO/INIAP Flavor Project ( Sukha et al., 2008 ). Table 1. Soil and weather characteristics at three cacao test sites in Puerto Rico. Performance Of the 40 clones selected
Elizabeth A. Baldwin, Myrna O. Nisperos-Carriedo and Jacqueline K. Burns
`Valencia' oranges were-treated with an experimental polysaccharide-based coating, a commercial shellac-based water wax, or were left uncoated. The fruit were stored at 16 or 21C with 95% RH. Samples were periodically analyzed for internal gases, flavor volatiles, water loss, and `Brix. Coated fruit had lower internal O2 and higher CO2 and ethylene levels as well as higher levels of many flavor volatiles (including ethanol) compared to uncoated. The differences were greatest for shellac-coated fruit at the higher storage temperature. No differences were found for °Brix. The shellac-coating gave the best weight-loss control and the most restricted gas exchange. The low gas permeability characteristic of this type of shellac coating may result in altered flavor for fruit held at 21C.
Valeria Sigal Escalada and Douglas D. Archbold
; Rupasinghe et al., 2000 ). These compounds are commonly used along with cold storage to manage apple fruit ripening. Several quality factors influence the acceptability of apples, including appearance, texture, and flavor. Flavor is a complex trait composed
Diana Dostal Lange and Randolph M. Beaudry
Low O2 and high CO2 concentrations can be used effectively to slow respiration and retard decay, but anaerobic and C02-injurious conditions must be avoided. The objective of this research was to: 1) determine the effects of low O2 and very high-C02 on flavor quality and accumulation of fermentation products. Strawberries and blueberries were stored in 2% O2/0% CO2, 20% 02/50% CO2, 2% O2/50% CO2, and 20% 02/0% CO2 for 0, 2, 4, 6, and 8 days at 20C. A taste panel evaluated the berries at the end of each storage period and again after 2 days under ambient conditions. Ethanol was the primary fermentation product that accumulated in response to low O2 and high CO2 concentrations. However, acetaldehyde was produced preferentially in response to elevated C02 levels. The flavor quality of the strawberries and blueberries was only acceptable for 2 days for treatments containing 50% CO2. The most intense off-flavors were detected in the 2% 02/50% CO2 and 20% O2/50% CO2 samples. 50% CO2 was highly effective in preventing decay, but this concentration was too high for acceptable flavor quality for storage periods greater than 2 days.