Evaluation of Roma Tomato (Solanum lycopersicum) Peeling Methods: Conventional vs. Power Ultrasound

Cheryl Rock, Wade Yang, Jyotsna Nooji, Arthur Teixeira, Hao Feng


Tomatoes are mainly consumed in processed form, which often requires peeling prior to processing. Conventional methods of peeling tomatoes includes the use of lye at considerably high concentration (10% to 15%), which generates increasing concerns on its disposal and environmental impacts, as well as material costs. In addition, lye has resulted in high peeling losses that adversely affected the yield of product. In this study, a comprehensive evaluation of peeling methods: lye (2% or 10%), power ultrasound, and lye (2%) in combination with power ultrasound were conducted. Peeling performances were evaluated based on ease of peeling and peeling losses of tomatoes after treatments. Results showed that peeling with power ultrasound in hot water yielded better ease of peeling score and much lower peeling losses than conventional lye peeling (P < 0.05). Peeling with much reduced lye concentration (2%) generated statistically (P < 0.05) comparable ease of peeling scores to the conventional 10% lye. Tomatoes treated with low concentration lye (2%) in combination with power ultrasound resulted in significantly ((P < 0.05) lower peeling losses compared to 2% or 10% lye. It was also found that further increase of exposure time to 75 s did not significantly ((P < 0.05) improve ease of peeling scores. Our findings suggest that ultrasonic power strength, not duration, was key to effective peeling and that 2% lye might be as effective as 10% for lye peeling.


Solanum lycopersicum, peeling loss, peeling performance, lye

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