Pomegranate aril drying and juice powder production

In this study, Hicaz type pomegranate (Punica granatum) juice powder and dry arils were obtained by spray drying, and hot air and microwave drying processes, respectively. In order to prevent stickiness problem in spray drying of juice, maltodextrin DE6 was used as a drying agent. Feed flow rate, feed temperature and air flow rate were kept constant. Air inlet temperature (110-140 °C), maltodextrin ratio in the feed mixture (39.08-64.12 %), and feed mixture concentration (19.61-44.11 °Brix) were the independent process variables.As it was aimed, the products with high yield (86 %) and high antioxidant activity (77 %) were produced. It was found that the most important variables were maltodextrin ratio and drying temperature in production of pomegranate juice powders. Total color change ( ? E), bulk density, antioxidant capacity and powder yield were strongly affected from independent variables. Therefore, these parameters were used in optimization process of independent variables. The optimum temperature, feed mixture concentration and maltodextrin ratio were estimated as 100 °C, 30.8 °Brix and 53.5 % maltodextrin, respectively.In the pomegranate aril drying part of this study drying behavior, shrinkage, rehydration, bulk density and color changes of the products were investigated. Hot air drying process was carried out at three different temperatures; 50, 60 and 70 °C. Also, three microwave power levels (210, 350, and 490 W) were studied as another drying technique. Increasing drying temperature and power intensity shortened the drying time of arils. Rate of drying was higher when microwave was used compared to air drying process. It was observed that shrinkage of air dried samples was higher than microwave dried sample. Rate of rehydration of microwave dried aril samples was relatively faster than air dried samples, but not significant. However, bulk density of air dried samples was higher than microwave dried sample.