Insights into the chemosensory basis of flavor in table grapes

Abstract

BACKGROUND: The full flavor of grape berries is determined by the interaction of sugars, acids, volatile compounds, and other berry properties, such as astringency. Sugars and acids are important for berry taste, whereas volatile compounds are important for the unique berry flavors, e.g., monoterpenes for the Muscat varieties. RESULTS: We explored the basis for 'fruity' flavor perception in table grapes. Samples were collected from 134 new table grape lines and commercial varieties and tested chemically for their volatile profiles and organoleptically by tasting panels. At the sensory level, flavor impression was strongly correlated with berry preference, whereas among 'fruity', 'neutral', 'herbaceous,' and 'Muscat', only the 'fruity' flavor was correlated with berry preference. At the chemical level, 114 volatile compounds were detected in the 81 breeding lines and cultivars examined, and grouped into 'core' and 'unique' categories. The typical berry flavor seemed to depend on the major volatile aldehydes -1-hexanal and (E)-2-hexenal -accounting for up to an average 85% of the berry's core volatile concentration. We found four volatile compounds --bergamotene, geranyl formate, aristolene and -penansinene -previously undetected, to our knowledge, in fresh grape berries.CONCLUSIONS: High 'fruity' flavor scores were related to three independent factors: (i) presence of unique volatile compounds, such as the sesquiterpene -copaene, (ii) higher total concentration of volatile compounds, (iii) optimal maturity associated to high total soluble solids (TSS) levels, interacting with berry volatile composition. These combined sensory and analytical data on the flavor of table grapes improve our understanding of the complex interface between chemical and sensory perception in fruit.

Ripening and Storage Time Effects on the Aromatic Profile of New Table Grape Cultivars in Chile

“…They are derived from linoleic and linolenic acid and have been described as the basic background volatiles in table grape berries [ 5 , 20 ]. Among them, it was found that hexanal and ( E )-2-hexenal were the major compounds in all the grape varieties, which was in agreement with previous studies [ 11 , 21 , 22 ]. The amount of hexanal found in Krissy was significantly lower than the quantities present in the other four varieties analyzed.…”

“…The amount of hexanal found in Krissy was significantly lower than the quantities present in the other four varieties analyzed. The ratio of hexanal to ( E )-2-hexenal was recently correlated with sweetness [ 22 ], and these compounds have also been quoted as the most active C6 compounds in table grapes and, therefore, are important contributors to the perceived aroma of this fruit [ 5 ].…”

“…In addition to C6 compounds, another essential contributor to grape aromas is the terpene group, which provides positive characteristic floral/fruity/citric aromas [ 22 , 24 ]. As mentioned above, two clear groups could be formed on the basis of the terpene compositions, with Magenta, Krissy, and Arra15 showing higher abundances.…”

Aroma Compounds Are Responsible for an Herbaceous Off-Flavor in the Sweet Cherry (Prunus avium L.) cv. Regina during Fruit Development

“…Interestingly, the concentration of benzaldehyde decreased at a slower rate and later in affected than in non-affected cherries (after stage 4), but the total content was higher at phenological stage 5 in the affected cherries. The C6 aldehydes hexanal and (E)-2-hexenal have been well described as green-herbaceous contributors to the aroma and flavor of fruits [40,41], and they are produced from fatty acids through the lipoxygenase (LOX) pathway [42,43]. There were no significant differences in the levels of these compounds between the affected and non-affected cherries within the same orchard (considering the six localities).…”

Linking sensory and proton transfer reaction–mass spectrometry analyses for the assessment of melon fruit (Cucumis melo L.) quality traits

“…Aprea et al [14] observed a negative contribution of 3-hexenol to the sweet perception of apple, whereas Klee and Tieman [47] reported a positive contribution to the 'overall flavor intensity' and 'liking' of tomato. Other authors observed the negative contribution of hexenal to the 'overall flavor intensity' and 'liking' of strawberries and blueberries [47], as well as to the sweetness of table grapes [48]. Besides, the interactions between certain VOCs with sugars and acids affect the rate of release and persistence of these volatile compounds in the mouth and, thus, the perceived intensities of aroma and flavor attributes [15].…”