Elizabeth A. Baldwin

Coarse chop partially deodorized tomato puree was spiked with 1 to 3 levels of individual food‐grade volatiles, reported to contribute to tomato flavor or volatile mixes and presented to a trained descriptive panel for flavor analysis in 2 different years. Six to eight panelists rated 9 aroma, 8 taste, and 1 aftertaste descriptors on a 15‐cm unstructured line scale. Panelists detected significant differences ( P ≤ 0.15) in concentration for various individual aroma compounds for a range of descriptors. Various descriptors also had correlations with levels of individual volatiles, including acetaldehyde, linalool, citral, trans‐2‐trans ‐4‐decadienal, furaneol, 1‐octen‐3‐one, and benzaldehyde. Of the combined volatile mixes in either year 2000 or 2001, spiked levels of the “green” mix (including with isobutylthiazole) resulted in increased perception of overall green and vine aromas as well as decreased perception of floral aroma, sweet taste, and overall aftertaste. The “earthy” mix resulted in increased perception of vine, earthy, and musty aromas as well as sweet taste, and decreased perception of overall and sour tastes. The “fruity” mix increased perception of overall, sweet tomato, tropical, and floral aromas as well as sweet, tropical, fruity, and overall aftertastes. The “fruity” mix also decreased green and musty aromas as well as sour and ripe tomato tastes. Principle component analysis (PCA) revealed that spiking with “earthy” and “green” mixes and 1‐penten‐3‐one were drivers for high loadings on the earthy and green descriptors, whereas the “fruity” mixes, furaneol, β‐ionone, benzaldehyde, and 2‐phenylethanol were drivers for high loadings on sweet tomato and floral aromas.

`Gala' apples [ Malus silvestris (L.) var. domestica (Borkh.) Mansf.] were treated with ethanol vapor (5 mL·kg ^-1 fruit for 24 hours at 25 °C), heat (4 days at 38 °C and >98% RH), or 1-methylcyclopropene (1-MCP; 1 or 0.625 μL·L ^-1 for 18 hours at 20 °C) before processing into slices, then dipped in anti-browning solutions or coatings, drained, and packaged in perforated polyethylene bags. Residual effects of pretreatments on fresh-cut slice physiological and quality attributes were investigated during storage for up to 19 days at 5.5 °C. Ethylene production was reduced by ethanol, heat, and 1-MCP pretreatments, while ethanol and heat also reduced slice respiration. Heat and 1-MCP pretreatments inhibited slice texture changes, while ethanol had no effect on instrumental texture measurements but reduced sensory firmness. Ethanol pretreatment increased the contents of ethanol and ethyl esters in slices but reduced acidity, while heat reduced both acidity and aroma volatile levels. Both ethanol and heat pretreatments led to lower sensory scores for apple flavor and ethanol-pretreated slices also received higher scores for altered flavor, although all scores were in the acceptable range. Slice acidity was best maintained by 1-MCP pretreatment. Shelf life based on appearance was 15 to 16 days for ethanol-pretreated slices and 12 days for heat-pretreated slices compared to that of control, which was 8 to 9 days, while 1-MCP pretreatment promoted decay development on the cut surface, which reduced the shelf life to 7 to 8 days. Obvious separations were determined between ethanol- and heat-pretreated slices and untreated control by canonical discriminant analysis of headspace volatile levels determined by GC and electronic nose. Therefore, pretreatments with ethanol and heat are very effective for prolonging visual shelf life at the expense of aroma quality.

Twelve tomato selections were evaluated for their flavor components using sensory and chemical/instrumental measurements. Regression analysis was performed to develop prediction models for the sensory descriptors. Significant prediction models were obtained for most descriptors. Both volatile and nonvolatile flavor components influenced the aromatic descriptors, but the volatile components provided more consistent relationships. Sucrose equivalents provided more significant correlations with descriptors than did soluble solids. Tomatoes described as full flavored by the breeder were characterized by higher sugars, soluble solids, aromatic volatile compounds, and lower amounts of organic acids than those considered to be of poorer flavor by the breeder. These data provide quantitative linkages of aromatic volatile compounds, sugars, and acids with specific flavor notes.

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.