Abstract

The aim of this study is to describe the drying kinetics of a murta (Ugni molinae Turcz) berry puree to obtain a fruit leather through mathematical model and determine the effect of different hydrocolloids on the mass diffusion coefficient, activation energy, surface color, and texture profile at different drying temperatures. Three hydrocolloids were used: 1% gelatin, 0.2% carrageenan, and 4% starch at three process temperatures: 50, 60, and 70 degrees C and a formulation without hydrocolloid as control. The hydrocolloids and process temperature influenced the drying time. The mass diffusion coefficient varied depending on the process temperature and hydrocolloids with values between 1.2665 x 10(-10) m(2) s(-1) and 4.5341 x 10(-10) m(2) s(-1). The Midilli & Kucuk model had a better fit to experimental values. A MANOVA indicated that hydrocolloids and process temperature had a significant effect on color and texture of fruit leather. The process temperature and concentration of hydrocolloids are important factors for drying process design. Practical Applications Fruit leather is a low humidity product and stable at room temperature. It can be made with surpluses, discards, or mixtures of fruits, being a new alternative of preservation and healthy consumption. The murta berry is a stationary fruit with antioxidant properties hardly been explored at an industrial level and fruit leathers can be a novel production alternative. Hydrocolloids have gelling and stabilizing characteristics. For this reason, they are used to improve the formation of fruit leathers, although it is necessary to know their effects on physical characteristics as color and texture of the final product. These features are important for consumers' purchasing decision. The convective drying process parameters for fruit leather production as: moisture content, diffusion coefficient, and activation energy can be determined by mathematical modeling. The knowledge of these parameters is important for drying process designs.