Effect of Fruit Ripeness when Picked on Flavor and Composition in Fresh Market Tomatoes1

Abstract

Composition and sensory characteristics were investigated to determine the effect of ripeness at picking on fresh market flavor of ‘Cal Ace’ (1974, 1975, 1976) and ‘Cherry’, ‘Calmart’, and ‘Early Pak 7’ (1976) tomato (Lycopersicon esculentum Mill.). Tomatoes picked at earlier stages of ripeness and ripened at 20°C were evaluated by panelists as being less sweet, more sour, less “tomato-like” and having more “off-flavor” than those picked at the table-ripe stage. Objective tests showed these fruits had less sugars and reduced ascorbic acid, and varied significantly in volatile composition. The magnitude of these differences varied greatly among the cultivars. In ‘Cal Ace’ the “off-flavor” characteristic was largely correlated with a volatile compound (peak 43) but in other cultivars seven other volatile compounds also appeared to play a role.

Amino Acid Composition and Flavor of Fresh Market Tomatoes as Influenced by Fruit Ripeness When Harvested1

“…We conclude that glutamic acid does not play a direct role in the "off-flavor" defect of tomato fruits harvested at the green or breaker stage and ripened off the plant, relative to those ripened on the plant. It is also clear from this study that differences in amino acid composition are less important to tomato flavor than differences in other non-volatile compo nents and in volatile compounds which we previously reported (6). Future studies, however, should consider possible interac tions among all constituents including the major amino acids in relation to flavor quality.…”

“…2). This "off-flavor" characteristic was detected by the panelists and was scored among other flavor characteristics in the 1975 study (6).…”

“…Field ambient temp during this period fluctuated between a mean minimum of 14.7°C and a mean maximum of 33.3°. Fruits were harvested at the dark-pink (DP), light-pink (LP), breaker (B), or full-sized green stages of maturity and ripeness (6), then held at 20° in glass 20-liter jars under a humidified air flow (about 100% relative humidity) until the table-ripe (TR) stage. No effort was made to exclude light during ripening.…”

“…Sensory evaluation. Procedures used in 1975 to score flavor characteristics including "off-flavor" were described in a previ ous report (6). In 1976 table-ripe fruits with or without added monopotassium glutamate at 60 mg/ 100 g of diced fruits were compared in 2 triangle tests by a trained panel of 15 judges.…”

“…One striking observa tion was the detection of increased "off-flavors" in fruits harvested greens or breakers and ripened off the plant rela tive to those picked table-ripe. Although the magnitude of this "off-flavor" was coincident with the concn of some volatile compounds, nonvolatile components (sugars and acids) ap peared to influence the impact on these volatiles (6). The ob jectives of this study were to determine if differences exist in free amino acids composition among tomato fruits picked at several stages of maturity and ripeness and whether possible differences are related to the "off-flavor" defect.…”