Combination of ultrasound and ultraviolet‐C irradiation on kinetics of color, firmness, weight loss, and total phenolic content changes in tomatoes during storage

Abstract

A kinetic study was conducted to account for the changes occurring in color, firmness, weight loss, and total phenolic content of tomatoes subjected to combined ultrasound technology (40 kHz, 13.78 W/L) and ultraviolet-C radiation (639.37 µw/cm2) treatment for 28 min. Combined treatment delayed ripening, increased firmness, weight loss, and induced total phenolic content retention of tomatoes compared to untreated samples. The change in color parameters of hue angle and chroma was described using the fractional conversion and zero-order models, respectively. Fractional conversion kinetic model was also found suitable for firmness degradation, while the zero-order and first-order models were appropriate for change in weight loss and total phenolic content retention prediction, respectively. Activation energy for measured parameters ranged from 121.29 to 199.70 kJ/mol at a temperature range of 33.76–37.12ºC, and showed highest sensitivity to treatment temperature in reduced ranking for firmness degradation, weight loss, total phenolic content retention, hue angle, and chroma. Practical applications The research provides a new method for postharvest handling of fruits and vegetables. The method utilizes ultrasound technology and ultraviolet-C radiation in combination and finds potential application in industries for shelf life extension during the storage, processing, and supply chain management of fruits and vegetables. However, the method may result in undesirable changes like weight loss, physical softening, or bioactive content degradation. Optimized parameters of the method are essential for loss minimizations and cost-effective practical applications. A thorough understanding of the influence of temperature of the system, treatment time, ultrasound acoustic energy density, and ultraviolet-C dosage on the quality properties of tomatoes and their change kinetics through fundamental approach modeling as presented in this research, is a step toward optimization of the technology.