Peeling of tomatoes using novel infrared radiation heating technology

A pilot scale electrical infrared dry-peeling system for tomatoes: Design and performance evaluation

“…Based on the results from several consecutive seasons, compared to conventional lye peeling, IR dry-peeling of tomatoes had a lower peeling loss, a thinner thickness of peeled-off skin, and a firmer texture of peeled products while achieving a similar ease of peeling. At a microscopic scale, the IR thermal effects were characterised by the melting of extracellular cuticles, collapse of surface cellular layers, thermal expansion and then severe degradation of cell wall structures, which essentially increased the peel stiffness and reduced the peel adhesiveness (Li, Pan, Atungulu, Wood, & McHugh, 2014;Li, Pan, Atungulu, Zheng, et al, 2014). All these findings demonstrated the promising potential of IR dry-peeling as a sustainable technology for the peeling of tomato and other vegetables.…”

“…During IR heating, IR radiation impinges on the tomato surface and the absorbed fraction creates a high amount of thermal energy, resulting in reduced skin failure strength and an increase in the internal water vapour accumulated under the skin membrane. When the vapour accumulates to a certain level, cracks occur in the tomato skin because the shear stress due to IR heating exceeded the critical rupture stress in the skin membrane (Li, Pan, Atungulu, Zheng, et al, 2014). Hence, introducing a partial vacuum outside the tomato immediately after the IR heating would enlarge the pressure difference across the skin membrane and enhance the formation of cracks, which may result in better peelability and ease of peel removal.…”

“…The firmness of peeled tomatoes was measured using a fruit texture analyser (model TA-XT2i, Texture Technologies Corp., N.Y., USA) through a plate compression test. A 25 mm diameter probe with a flat surface was used to compress the horizontally aligned (blossomestem axis) whole peeled tomato by a distance of 5 mm under 5 mm s À1 forward speed (Cantwell, 2006;Li, Pan, Atungulu, Zheng, et al, 2014). All reported values for firmness are the average of ten replicates.…”

“…The vacuum and pinch roller sections are similar to the systems commonly applied in the tomato industry. Key parameters underlying the design are primarily drawn from our previous experimental and mathematical modelling studies (Li & Pan, 2014b;Li, Pan, Atungulu, Zheng, et al, 2014). Each section is described in details below.…”

Washing, Peeling and Cutting of Fresh-Cut Fruits and Vegetables

“…In addition, the treatment resulted in melting of cuticular membrane, collapse of several cellular layers, and severe degradation of cell wall structures. This caused easy peel separation (Li et al 2014a ).…”