Dried and concentrated products from mulberry (Morus alba and Morus nigra) and the changes during their processing

In this study, some drying behaviors (drying curves, shrinkage and color changes) of white mulberry (Morus alba) and black mulberry (Morus nigra) have been studied for hot air and microwave drying. Hot-air drying was followed at three different temperatures as 60, 70 and 80oC and it was observed that the increasing temperature caused significant reduction in drying time. When microwave energy was used instate of hot-air drying, reduction in drying time was also observed. It was found that both microwave and hot-air drying methods caused strong change on color as a function of time. The color deterioration rate was faster for microwave drying; however when the samples reached to equilibrium in drying, there was no significant difference in their final color values. Both type of mulberries showed a significant shrinkage.The mulberry juice concentrates were produced by using various heating methods such as atmospheric, microwave and rotary vacuum. The concentration by microwave technique reduced time of evaporation considerably. A shorter time compared to atmospheric conditions and the best color quality compared to the two other techniques have been found for rotary vacuum concentration.