). In the past, selection for flavor in the UF breeding program was based on subjective breeder ratings and calculation of a sugar/acid ratio (soluble solids content/titratable acidity). However, eating quality of blueberries has been shown to have a
Flavor quality is one of the most difficult traits to select in plant breeding programs due to the large number of sensory panelists required, the small number of samples that can be evaluated per day, and the subjectivity of the results. Using sweetpotato [Ipomoea batatas (L.) Lam.] as a model, clones exhibiting distinctly different flavors were analyzed for sugars, nonvolatile acids, and aroma chemistry to identify the critical flavor components. Differences in sugars, sucrose equivalents, nonvolatile acids, and 19 odor-active compounds were identified that accounted for differences in flavor among the clones. Using the intensity of the aroma per microliter for each of the 17 most important aroma-active compounds (maltol, 5-methyl-2-furfural, 2-acetyl furan, 3-furaldehyde, 2-furmethanol, benzaldehyde, phenylacetaldehyde, β-ionone, 1,2,4-trimethyl benzene, 2-pentyl furan, 2,4-decadienal, 2,4-nonadienal, linalool, geraniol, cyperene, α-copane and a sesquiterpene) and the relative sweetness of individual sugars × their respective concentrations, multivariate (principal component and cluster) analysis allowed accurate classification of the clones according to flavor type without sensory analysis. The level of precision was such that sweetness, starch hydrolysis potential, and the concentration of β-carotene could be accurately predicted by quantifying specific volatiles. Analytical assessment of flavor would greatly facilitate the accurate evaluation of large numbers of progeny, the simultaneous selection of multiple flavor types, and the development of superior new cultivars for a wide cross-section of food crops.
Abstract
The instrumentation required for objective evaluation of flavor has been available for only a decade and a half. Most information on the chemistry of flavor has accumulated within the past 5 years. There have been few studies on intercultivar variation of compounds important to flavor. Because an appreciation of the physiology of flavor and an understanding of flavor chemistry are basic to the genetics of flavor, it seems appropriate to discuss briefly these topics.
Dimethyl sulfide (DMS) has been identified as the compound responsible for the characteristic aroma of cooked sweet corn (Zea mays L.) and, along with sugar and water-soluble polysaccharides, is one of the main flavor components in the kernels. Because of the close relationship between DMS and its amino acid precursor S-methylmethionine, the premise was formulated that it might be possible to improve sweet corn aroma and overall eating quality through enhanced production of DMS from increased application of N and S to the crop in the field. Studies were conducted on a Plainfield sand and a Flanagan silt loam to evaluate the effects of N and S fertilization on kernel DMS production in several commercial sh2 hybrids; in the process, the effect of N and S fertilization on various yield and yield component parameters was also determined. Hybrid was the main factor affecting kernel DMS production, although in both soils kernel DMS levels were influenced by significant interactions between hybrid and fertilizer treatments. Kernel DMS content, in response to increasing N fertilization rates, increased by an average of 85% in three of six hybrids in the Plainfield sand and by 60% in two of three hybrids in the Flanagan silt loam. The effect of S fertilization on kernel DMS production was small, with only one hybrid on the sandy soil showing a positive response (38%) to S application, and then in combination with high N rates. Irrespective of N-S fertilization regime, kernel DMS concentrations decreased at both locations by an average of ≈8.5% per day as kernel maturity increased. The results showed that kernel DMS production may be enhanced by N nutrition, independent of N fertilization effects on ear and kernel yields.
, Forastero, and Trinitario) were recognized within cacao, based on genetic origin, pod morphology, and size, as well as, color and flavor of beans ( Engels, 1981 ; Laurent et al., 1994 ; Toxopeus, 1985 ). Motamayor et al. (2008) in a study of cacao
Three onion (Allium cepa L.) cultivars were grown to maturity at five S fertility levels and analyzed for S-alk(en)yl-L-cysteine sulfoxide (ACSO) flavor precursors, γ-glutamyl peptide (γ-GP) intermediates, bulb S, pyruvic acid, and soluble solids content. ACSO concentration and composition changed with S fertility, and the response was cultivar dependent. At S treatments that induced S deficiency symptoms during active bulbing, (+)S-methyl-L-cysteine sulfoxide was the dominant flavor precursor, and the flavor pathway was a strong sink for available S. As S fertility increased to luxuriant levels, trans(+)-S-(1-propenyl)-L-cysteine sulfoxide (PRENCSO) became the dominant ACSO. (+)S-propyl-L-cysteine sulfoxide was found in low concentration relative to total ACSO at all S fertility treatments. With low S fertility, S rapidly was metabolized and low γ-GP concentrations were detected. As S fertility increased, γ-GP increased, especially γ-L-glutamyl-S-(1-propenyl)-L-cysteine sulfoxide, the penultimate compound leading to ACSO synthesis. Nearly 95% of the total bulb S could be accounted for in the measured S compounds at low S fertility. However, at the highest S treatment, only 40 % of the total bulb S could be attributed to the ACSO and γ-GP, indicating that other S compounds were significant S reservoirs in onions. Concentrations of enzymatically produced pyruvic acid (EPY) were most closely related to PRENCSO concentrations. Understanding the dynamics of flavor accumulation in onion and other vegetable Alliums will become increasing important as the food and phytomedicinal industries move toward greater product standardization and characterization.
53 ORAL SESSION 7 (Abstr. 438-444) Cross-commodity: Postharvest Physiology/Food Science/Flavor/Nutrition/Quality
53 ORAL SESSION 7 (Abstr. 438-444) Cross-commodity: Postharvest Physiology/Food Science/Flavor/Nutrition/Quality
53 ORAL SESSION 7 (Abstr. 438-444) Cross-commodity: Postharvest Physiology/Food Science/Flavor/Nutrition/Quality
conditions that differ more significantly among organic farms. Because of the difference in the production conditions and the market objectives, the desirable traits for a variety differ for organic and conventional farmers. Flavor is the top priority for