Effect of Endogenously Synthesized and Exogenously Applied Ethanol on Tomato Fruit Ripening

Abstract

Tomato (Lycopersicon esculentum Mill. var Castlemart) fruit ripening was inhibited by tissue concentrations of ethanol that were produced by either exposure to exogenous ethanol vapors or synthesis under anaerobic atmospheres. Ethanol was not detected in aerobically ripened tomato fruit. Ripening was not inhibited by exposure to methanol at an equivalent molar concentration to inhibitory concentrations of ethanol, while ripening was slightly more inhibited by n-propanol than by equivalent molar concentrations of ethanol. The mottled appearance of a few ripened ethanol-treated fruit was not observed in n-propanol-treated fruit.and, at some stages of maturity, stimulated respiration and ethylene synthesis ofJapanese persimmon (10, 1 1). Acetaldehyde promoted ripening and ethylene synthesis in pears (14) and promoted color formation and a climacteric-like respiratory rise in blueberry and strawberry fruit (15). Treatment of blueberries, tomatoes, and pears with ethanol or acetaldehyde vapors increased their sugar content and sugar-acid ratio and induced desirable flavor changes (23). These compounds were less effective in promoting color changes than ethylene but had a more positive effect on flavor.A previous communication from this laboratory (26) reported inhibition of ripening of tomato fruit by ethanol. In the study described here, we have further investigated this phenomenon to better characterize the role of ethanol in fruit ripening.

Role of internal atmosphere on fruit ripening and storability—a review

“…These volatiles may be accumulated or released differentially and thereby influence the ripening process in fruits (Cadwallader 2005;Pesis 2005Pesis , 2006. This has been demonstrated for the ripening of climacteric fruits like; tomato (Kelly and Saltveit 1988;Saltveit and Sharaf 1992;McDonald et al 1996) and apple (Pesis et al 1994;Pesis 1995). Besides this, levels of volatiles are also found to be associated with storage disorders of apple fruit like; scald (Huelin and Coggiola 1968) and internal browning (Mendoza et al 2007).…”

“…Besides this, high CO 2 and/or low O 2 within the atmosphere of the fruit can induce anaerobic metabolism resulting in enhanced accumulation of ethanol and acetaldehyde (Kader 1987). Ethanol and acetaldehyde were in fact reported to delay the ripening of tomato fruit (Kelly and Saltveit 1988;Beaulieu et al 1997). This thereby explains the reason behind the retardation of ripening process due to short period of anaerobiosis treatment prior to the storage of tomato fruits as observed by Kelly and Saltveit (1988), Pesis and Marinansky (1993) and Paul and Srivastava (2006).…”

“…Ethanol and acetaldehyde were in fact reported to delay the ripening of tomato fruit (Kelly and Saltveit 1988;Beaulieu et al 1997). This thereby explains the reason behind the retardation of ripening process due to short period of anaerobiosis treatment prior to the storage of tomato fruits as observed by Kelly and Saltveit (1988), Pesis and Marinansky (1993) and Paul and Srivastava (2006). CO 2 at the level of 10 kPa in combination with 6 kPa of O 2 was suggested to be suitable for cold storage for late and early harvested grapes up to 12 weeks and 4 weeks, respectively as this limits the losses due to gray mold (Crisosto et al 2002).…”

“…During anoxia (Jackson et al 1982), 3. Under few days of anaerobiosis (Kelly and Saltveit 1988), 4. Under stress (Kimmerer and Kozlowski 1982) and 5.…”

“…Under stress (Kimmerer and Kozlowski 1982) and 5. Fruits exposed directly to ethanol vapours (Kelly and Saltveit 1988). Ethanol appears to inhibit not only the synthesis of ethylene but its action as well (Ritenour et al 1997;Saltveit and Mencarelli 1988;Pesis 2005;Asoda et al 2009).…”