Ethanol Vapor Vacuum Infiltration of Tomatoes: Morphological Analysis and Effect on Ripening and Eating Quality

Abstract

<jats:p>Tomatoes (<jats:italic>Lycopersicon esculentum</jats:italic> Mill. `Bermuda') were vacuum infiltrated at the breaker stage with 25 to 55 mL·L<jats:sup>-1</jats:sup> ethanol (EtOH) vapor at a 10 kPa pressure for 5 minutes and then held for a further period before ripening in air at 22 °C. Fruit could tolerate these EtOH vapor concentrations for no longer than 0 to 12 hours after vacuum infiltration, depending on concentration; otherwise skin pitting, uneven ripening and off-flavors resulted. Noninjurious conditions delayed ripening, as judged by color change, by an additional 1 to 5 days compared with 4 days for the control; aroma or flavor were not altered as determined by a trained taste panel, except in extreme conditions where in some cases off-flavors increased. Soluble solids and titratable acidity did not vary, but pH increased by 0.1 units in some treatments. In control fruit EtOH was found only in the gel tissue, and acetaldehyde (AA) was higher in the gel tissue compared with the pericarp and columella, indicating different metabolic behavior of the various tomato tissues. During vacuum exposure, EtOH moved through the stem scar and to a much lesser extent through the epidermis; during subsequent exposure to EtOH more EtOH moved through the epidermis than before, but still less than through the stem scar. AA increased following EtOH uptake, but all increases in EtOH and AA disappeared before fruit ripened.</jats:p>

Postharvest treatments to mitigate the internal browning in ‘Bartlett’ pears

“…Particular fruit structural morphologies such as the stem scar and thin skin favor ethanol diffusion into the internal tissues and can contribute to changes in flavor and taste. As reported by Ratanachinakorn et al (1999), tomato aroma and flavor were altered in extreme conditions when off-flavors increased.…”

“…Ritenour et al (1997) did not find significant inhibition of ripening in pears, bananas, honeydews, muskmelons, nectarines, peaches and plums when exposed to ethanol vapors. On the other hand, ripening of tomatoes at various ripening stages was delayed by EtOH vapor treatments (Kelly and Saltveit, 1988;Saltveit and Sharaf, 1992;Ratanachinakorn et al 1999;Hong et al, 1995). According to Salveit (1989), the delay in ripening is likely to be a result of EtOH inhibiting the conversion of ACC to ethylene.…”

Heat and anaerobic treatments affected physiological and biochemical parameters in tomato fruits

“…The detected effect of anaerobic treatment on ripening delay is probably caused by fermentative metabolites like ethanol and acetaldehyde produced under this condition, though the ripening process can be restarted when they dissipate (Ratanachinakorn, Klieber, & Simons, 1999). An increased acetaldehyde concentration was reported to inhibit ethylene production and consequently delay chlorophyll degradation and lycopene synthesis (Saltveit & Mencarelli, 1988).…”

“…The ethanol reduction during storage could be related to the AA increase observed after 13 days of storage at the same temperature (S2o). Ratanachinakorn et al (1999) stated that an increment of ethanol induces the synthesis of ADH enzyme, the reversion of the reaction by a feedback mechanism, and consequently the transformation of the ethanol excess to AA. After 13 and 20 days of storage at 14 1C, only ANA6d treatment had a higher AA concentration than C. Fig.…”