The effectiveness of using infrared (IR) dry-peeling as an alternative process for peeling tomatoes without lye and
water was studied. Compared to conventional lye peeling, IR dry-peeling using 30 s to 75 s heating time resulted
in lower peeling loss (8.3%–13.2% vs. 12.9%–15.8%), thinner thickness of peeled-off skin (0.39–0.91 mm vs. 0.38–
1.06 mm), and slightly firmer texture of peeled products (10.30–19.72 N vs. 9.42–13.73 N) while achieving a
similar ease of peeling. IR heating increased the Young's Modulus of tomato peels and reduced the peel adhesiveness,
indicating the tomato peels to loosen, become brittle, and crack more easily. Also, IR heating resulted in
melting of cuticular membrane, collapse of several cellular layers, and severe degradation of cell wall structures,
which in turn caused peel separation. These findings demonstrated the effectiveness of the novel IR dry-peeling
process for tomatoes.
Industrial relevance: Development of a sustainable and non-chemical peeling technique for food processing industry
is urgent. Currently, industrialized peeling methods such as hot lye or steam peeling are water- and
energy-intensive operation and result in a large amount of waste effluent. Disposal of these wastewater containing
high salinity and organic solids poses negative environmental footprints. Tomato processors have long been
interested in pursuing a sustainable and non7 chemical peeling alternative in order to minimize waste effluent
containing high salinity and organic loads and reduce the negative environmental impacts associated with conventional
hot lye peeling. The emerging infrared dry-peeling technique offers a novel approach to eliminate the
usage of chemicals and water in the peeling process while maintaining high quality peeled products. The study
explored several crucial and fundamental aspects of developing infrared radiation heating technology as a sustainable
tomato peeling method. The findings of this research provide scientific evidence of the benefits of infrared
dry-peeling in comparison to the conventional hot lye peeling and have been used for the development of a
pilot scale tomato infrared dry-peeling system