REHYDRATION KINETICS OF DEHYDRATED BERRIES

Ígor H De M R Ciolin,Daiane C Lenhard,Carolina C Garcia,Camila W Antunes

doi:10.1590/1809-4430-eng.agric.v41n3p389-395/2021

Abstract

Cranberries and blueberries are small fruits known for their antioxidant properties. However, due to their high water content and short shelf life, they are generally marketed as dehydrated berries. The present work aimed to model the rehydration of dehydrated berries. Rehydration tests were conducted at 7 and 29°C using milk as a solvent and at 7, 29, and 45°C when the solvent was water. The mass gain was assessed at different intervals, and the experimental data were fitted to the Fick model considering the berries as spheres. Six empirical/semi-empirical models describing the diffusion of water during drying were used to predict the rehydration process. Fick’s law satisfactorily represented the data, and the highest diffusion coefficients were found when the berries were rehydrated in water at 45°C. Rehydration of berries in milk resulted in nutrient gain as different diffusive flows occurred during the process. The use of empirical models to predict the operating time of the rehydration processes allows flexibility as such models are mathematically simpler than the Fick model. Diffusivity is essential for the design/construction of equipment, and/or process optimization and implementation.

Highlights

The cranberry is a false berry with an intense red color and a very pronounced acid taste
Present in many fruits and vegetables, have been studied extensively for their high antioxidant power because they are capable of increasing resistance to oxidative damage caused by free radicals generated in the human body (Ho et al, 2020)
To verify the fit of the experimental data to the models, the magnitude of the coefficient of determination (R2), the root mean square error (RMSE), and the values of the relative mean error (P) were assessed, the latter calculated according to eqs (15) and (16), respectively

Summary

INTRODUCTION

The cranberry is a false berry with an intense red color and a very pronounced acid taste. Present in many fruits and vegetables, have been studied extensively for their high antioxidant power because they are capable of increasing resistance to oxidative damage caused by free radicals generated in the human body (Ho et al, 2020) They are beneficial to health, most berries, such as cranberries, blueberries, and raspberries, are traditionally grown in areas with cold climates, such as swamps and coniferous forests (Oszmiański et al, 2015), and must be harvested during a specific period, which is one of the factors limiting their consumption. Considering the nutritional value of berries, their unique taste and color, and their use in bakery products, while aiming to obtain the necessary data for construction/improvement of equipment and optimization of implemented processes, the present work studied the rehydration kinetics of dehydrated cranberries and blueberries

MATERIAL AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS