In this study, the effectiveness of IR dry-peeling of tomatoes was comprehensively investigated from multiple aspects, including physical attributes of tomatoes from different cultivars, peeling performance, peeled product quality, and biomechanical and anatomical features of IR peeled skins. The following conclusions were drawn:
(1)
Morphometric features, including the height of maximum lateral diameter, the ratio of height to maximum lateral diameter, the stem scar diameter, and the pericarp thickness, are important in distinguishing different tomato cultivars. However, these morphometric features may not significantly impact on peeling performance;
(2)
Compared to conventional lye peeling, IR dry-peeling using 30 to 75 s heating time showed a 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 to 19.72 N vs. 9.42–13.73 N) while achieving an ease of peeling higher than 4.0. For the cultivars studied, IR heating for 60 s is reasonable and can be expected to achieve an ease of peeling of 4.5 or higher;
(3)
Compared to control, IR heating reduced the energy to tear tomato peels by 42% for cv. AB2 and 56% for cv. CXD179. Reduced adhesiveness and increased peel brittleness after IR heating revealed the impacts of IR heating and built a foundation for more in-depth future analyses of changes in biomechanical properties of tomato peel;
(4)
IR heating resulted in melting of cuticular membrane, collapse of several cellular layers, and severe degradation of middle lamella and cell wall structures, which in turn caused skin separation. In order to achieve desired skin separation while