Improvements in drying characteristics and quality parameters of tomato by carbonic maceration pretreatment

Abstract

Effects of carbonic maceration (CM) on drying kinetics and some quality characteristics of dried tomato slices were evaluated. The response surface methodology was used to optimize CM pretreatment (temperature, CO2 pressure, time) for drying time (DT) and effective diffusivity (Deff). Drying process was accelerated by CM applied before conventional drying compared to control samples dried without CM pretreatment. DT and Deff were significantly affected by treatment conditions. CM significantly increased some color parameters (L*, a*, b*, and C*) but decreased total color change and browning index compared to control samples. Significant increments in water activity and titratable acidity were observed in CM treated samples, but textural properties were lower than control one. No significant differences were observed in pH, ascorbic acid content and a*/b* color parameter. Briefly, the CM was an effective pretreatment which could be applied before drying to improve drying characteristics. Practical applications One of the forms used by consumers and manufacturers is the dried tomato slices widely produced by a method of convectional hot air drying. However, the long drying time due in part to the structural characteristics of tomato skin may cause drastic changes in sensorial attributes such as flavor, color, and texture as well as physical properties and nutritional content of tomato. Carbonic maceration and its effects on drying characteristics were investigated in this regard. Results revealed high potential to provide improvement in drying characteristics such as drying time and effective diffusivity. Reduction in drying time by carbonic maceration is an economic advantage. Additionally, some quality parameters of tomato including color, texture, physical properties and ascorbic acid content were also investigated and results are found to be promising for the dried food stuff manufacturers.