EFFECT OF PRETREATMENT OF INTACT ‘ KENT ’ AND ‘ TOMMY ATKINS ’ MANGOES WITH ETHANOL VAPOR , HEAT OR 1-METHYLCYCLOPROPENE ON QUALITY AND SHELF LIFE OF FRESH-CUT SLICES

Treatments known to inhibit or delay ripening were applied to imported ‘Kent’ and ‘Tommy Atkins’ mangoes. Mangoes that were fairly firm, with some ground color development (‘Kent’) or hard with slight color blush (‘Tommy Atkins’) ripenness stage were treated with 1-methylcyclopropene (1MCP) at 25 ppm for 24 or 12 hours, respectively, ethanol (5.0 g·kg -1 fruit) for 24 or 8 hours, respectively, and heat (38 °C, 98% RH) for 24 or 12 hours, respectively. Treated fruit were cut 24 hours after treatment, and stored at 7 °C for 12 (‘Kent’) and 14 (‘Tommy Atkins’) days. For ‘Kent’ mangoes, 1-MCP and heat treatments decreased fruit firmness, while ethanol treatment maintained firmness similar to control. Similar differences between treatments were observed for cut fruit during storage. Heat treatment resulted in cut fruit with the lowest firmness and titratable acidity. Ethanol treatment significantly decreased the total soluble solids content of cut mangoes compared to all other treatments. After 12 days of storage, cut pieces from ethanol-treated mangoes maintained the best visual quality, and pieces from heat-treated fruit looked overripe. Informal tasting indicated off-flavor in pieces from ethanol-treated ‘Kent’ mangoes after 8 days in storage. For ‘Tommy Atkins’ mangoes, ethanol and 1-MCP treatments increased firmness, but only slices from 1-MCP-treated fruit remained firmer in storage. By reducing the duration of ethanol treatment to 8 hours on ‘Tommy Atkins’ intact mangoes, the off flavor noted for ‘Kent’ disappeared in stored slices, but other quality parameters were not improved. Heat and 1-MCP treatments resulted in higher L* value of stored cut pieces. Overall, no treatment extended fresh-cut mango shelf life for ‘Tommy Atkins’, but for ‘Kent’, spoilage was delayed by two days on all treated pieces. Because they require peeling and are juicy, mango fruit are not convenient to eat; additionally, most North American consumers are unfamiliar with mangoes. Currently, fresh-cut fruit found on supermarket shelves include pineapples, melons, apples, and grapes (Cooperhouse, 2003). Therefore, developing the technology for fresh-cut mangoes would add to the variety of available fresh-cut fruit, and it would offer consumers convenience for an exotic fruit that is both delicious and nutritious. Reports on the physiology and storage of fresh-cut mangoes are limited. Chantanawarangoon (2000) and Tovar et al. (2001) found that cut mangoes produced little CO 2 and ethylene in comparison to whole fruit, indicating that wounding would have a minimal impact on ethylene-induced ripening events. Lower storage temperatures (2 °C vs. 5 °C, or 5 °C vs. 10 °C) increased cut mango shelf life (Chantanawarangoon, 2000; Rattanapanone et al., 2001), and a controlled atmosphere with 10 kPa CO 2 extended potential marketability by 2 to 3 d (Chantanawarangoon, 2000; Limbanyen et al., 1998; Rattanapanone et al., 2001). Antibrowning and firming agents may help maintain the visual quality and firmness of mango pieces in storage (Chantanawarangoon, 2000; González-Aguilar et al., 2000). Most of the research and applications to increase shelf life of fresh-cut produce focus on preventing decay and foodborne disease development, and retarding events associated with tissue senescence, including softening and browning (Alzamora et al., 2000). Treatments to prevent these effects are performed on the fresh-cut product. Another concept is to subject the intact fruit to ripening inhibitors before cutting, with the assumption that inhibition has a residual effect on the cut product senescence (Bai et al., 2003; Jiang and Joyce, 2002; Saftner et al., 2001). 1-Methylcyclopropene (1-MCP), a competitive ethylene inhibitor, binds to the ethylene receptors in plant tissue much longer than ethylene (Sisler and Serek, 1997); therefore, it delays senescence of climacteric fruits long after its initial application (Fan et al., 1999; Roh et al., 2001). 1-MCP was recently approved by the Environmental Protection Agency for postharvest use on fruits and vegetables (Federal Register, July 26, 2002), and numerous publications showed its efficacy in retarding ripening events in fruits and vegetables. 1-MCP is therefore a good candidate as a pre-processing treatment for fresh cut products (Bai et al., 2003). Ethanol is another candidate with an inhibitory effect on ethylene production, resulting in delayed ripening in tomatoes (Beaulieu and Saltviet, 1997; Saltviet and Mencarelli, 1988; Yanuriati et al., 1999), avocado, honeydew and muskmelon when injected in the seed cavity (Ritenour et al., 1997), and mangoes (Abdulah and Basiouny, 2000). The mode of action of ethanol in the fruit would be by conversion to acetaldehyde, which in turn acts as an inhibitor of ethylene production (Beaulieu and Saltviet, 1997; Beaulieu et al., 1997). However, in practice, it is safer to use ethanol, less hazardous than acetaldehyde, which is highly volatile and toxic. Mention of a trademark or proprietary product is for identification only and does not imply a guarantee or warranty of the product by the U.S. Department of Agriculture. The U.S. Department of Agriculture prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. 1 Corresponding author.