Flame-catalytic infrared dry system for tomato continuous peeling

Abstract

To eliminate the need for alkali and excess water while accelerating the industrial application of dry tomato peeling, a highly efficient industrial flame-catalytic infrared continuous peeling apparatus was designed. The synthesis of the catalytic layer (Pt/Al2O3) within the device was optimized to improve cost-effectiveness and enable modular installation, making it suitable for industrial applications. This study determined the optimal production parameters for industrial flame-catalytic infrared peeling (F-CIP) through experiments. Current findings demonstrated that, under optimal F-CIP conditions, characterized by a flame heating time of 5.8 s, an infrared heating temperature of 456 °C, an infrared heating distance of 70.6 mm, and an infrared heating duration of 246 s, peeling efficiency reached 99.2±0.9 %, with a peel loss of 4.1±0.3 %. Comparative analysis with lye peeling (LP) and hot water peeling (HWP) showed that F-CIP reduced hardness and peel loss and better preserved nutritional and antioxidant compounds. The mechanism responsible for the loosening and cracking of the fruit skin in the F-CIP peeling process involved a reduction in adhesion between the skin and the pulp due to the alteration of the pectin structure, an expansion of cell structure due to internal vaporization, and an increase in the Young’s modulus of the tomato skin. The F-CIP method, with its proven peeling efficiency, energy-saving attributes, and environmentally friendly features, is expected to attract increased attention from equipment manufacturers and the tomato industry. This paper serves as a foundational guide and contributes to the application and parameter control of F-CIP in the tomato peeling.