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- Author or Editor: Leonard L. Morris x
Abstract
Sensory evaluations and chemical analyses were used to investigate the effects of various postharvest handling procedures on composition and flavor quality of ‘Cal Ace’ tomatoes (Lycopersicon esculentum Mill.) harvested at the mature-green and light-pink stages. Ethylene treatment to speed ripening of green tomatoes at 20°C resulted in a higher reduced ascorbic acid content at the table-ripe stage and did not influence flavor when compared with fruits ripened without added ethylene. Using a low-O2 atmosphere to retard ripening had less of an effect on flavor than stage of ripeness at harvest. No differences were found between fruits where ripening was delayed by using 4% O2-atmosphere at 20° or by using low temperature (12.5°). Exposing fruits to 5° for 7 days before ripening at 20° affected flavor; i.e., chilled fruits were more acid. Above the chilling range (0-12.5°); duration of holding after harvest was more important than storage temperature. Lower holding periods resulted in loss of characteristic “tomato-like” flavor and development of “off-flavors.” Mature-green fruits, ripened at 20° under restricted air flow, had increased “off-flavors” when compared to those ripened under accelerated air exchange. Light-pink fruits subjected to impact bruising before ripening had more “off-flavor” and less “tomatolike” flavor than those without physical damage. Quantitative differences in a few volatile components were found with certain treatments, but no qualitative differences were detected and there was no significant difference in total volatile content among any of the treatments tested.
Abstract
Four amino acids (glutamic, γ-aminobutyric, glutamine, and aspartic) make up about 80% of the total free amino acids in fruits of tomato (Lycopersicon esculentum Mill., cv. Cal Ace). Fruits harvested at the table-ripe stage contained more alanine and less glutamic acid than those picked green or at the breaker (incipient red color) stage and ripened at 20°C to table-ripe. The higher glutamic acid concentrations in fruit picked at the breaker or earlier stages were paralled to higher scores for “off-flavor,” as described by a taste panel, relative to fruits picked table-ripe. However, when monopotassium glutamate (60, 120, or 180 mg/l00g) was added to diced table-ripe fruits, the panelists were not able to detect flavor differences due to increased glutamic acid concn. Differences in amino acid composition associated with fruit ripeness when picked do not appear to be directly related to flavor differences.
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.
Abstract
Brown stain on crisphead lettuce (Lactuca sativa L. cv. Calmar) was increased by exposure to carbon monoxide (CO) combined with elevated CO2 (1, 2 or 5%) regardless of the O2 level (2, 5, 10, or 21%). Carbon monoxide at 1, 3, or 5% added to air without added CO2 did not induce brown stain. Holding under 5 or 10% O2 in combination with 1% CO2 and with or without 1% CO for 20 days followed by a 4-day period in air at 10°C resulted in better overall visual quality compared with air or 2% O2 controls. Carbon monoxide in combination with air or 2% O2 reduced the respiration rate of lettuce during a 10-day period at 2.5°C. Lettuce previously subjected to CO had higher respiration rates, relative to controls, during the subsequent 4-day period in air at 10°C.