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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #293945
Title: A comparison of dynamic mechanical properties of processing-tomato peel as affected by hot lye and infrared radiation heating for peeling

Author
item WANG, YONG - University Of California
item LI, XUAN - University Of California
item SUN, GANG - University Of California
item LI, DONG - China Agricultural University
item Pan, Zhongli

Submitted to: Journal of Food Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2013
Publication Date: 10/29/2013
Publication URL: http://dx.doi.org/10.1016/j.jfoodeng.2013.10.032
Citation: Wang, Y., Li, X., Sun, G., Li, D., Pan, Z. 2013. A comparison of dynamic mechanical properties of processing-tomato peel as affected by hot lye and infrared radiation heating for peeling. Journal of Food Engineering. DOI: 10.1016/j.jfoodeng.2013.10.032.

Interpretive Summary: Peeling is widely used in the food processing industry to produce premium quality canned fruits and vegetables. In this study, the effects of IR and lye peeling treatments on the dynamic mechanical properties of tomato peel were investigated with three dynamic mechanical analysis (DMA) test modes. The transition temperatures of infrared treated peels (63°C - 72°C) and lye treated peels (43°C - 75°C) were significantly lower than those of fresh control (about 88°C). Values of both storage and loss moduli of infrared heated peels were considerably higher than those of the fresh control, whereas values of the storage and loss moduli from the lye peeled samples were lower than those of fresh peels. DMA tests effectively differentiated the viscoelastic behaviors of tomato peels and indicated mechanistic differences between the lye peeling and infrared dry-peeling. The results can be used to determine the minimal temperature needed to achieve successful peel removal by means of IR heating.

Technical Abstract: This study investigated the viscoelastic characteristics of tomato skins subjected to conventional hot lye peeling and emerging infrared-dry peeling by using dynamic mechanical analysis (DMA). Three DMA testing modes, including temperature ramp, frequency sweep, and creep behavior test, were conducted to evaluate the transition temperatures and dynamic moduli of tomato peels heated by infrared radiation and hot lye at four heating durations (30, 45, 60, and 75 s). Fresh tomato peels were used as a control. Results showed that dynamic moduli of tomato peels were sensitive to temperature ramp and frequency sweep tests. Over a temperature range from 20°C to 100°C, transition temperatures of infrared treated peels (63°C - 72°C) and lye treated peels (43°C - 75°C) were significantly lower than those of fresh control (about 88°C). Values of both storage and loss moduli of infrared heated peels were considerably higher than those of the fresh control, whereas values of the storage and loss moduli from the lye peeled samples were lower than those of fresh peels. DMA tests effectively differentiated the viscoelastic behaviors of tomato peels and indicated mechanistic differences between the lye peeling and infrared dry-peeling.