Compositional Changes of the Jujube Fruit During Solar and Tray Drying

Abstract

In this study, jujube fruit (Zizyphus jujuba Mill.) was used as material. Jujube fruits were obtained from producer in Çivril-Denizli regions. Firstly, total solube solids, dry matter, titratable acidity, pH, total phenolic content, organic acid (malic, citric, succinic, and tartaric acid), sugars (glucose, fructose, and sucrose), and water-soluble vitamins (ascorbic acid, riboflavin, niacin, pyridoxine, and thiamine) in fresh jujube fruit were analyzed. Secondly, fresh jujube fruits were dried in a solar and tray dryer (50, 60, and 70 °C). Total phenolic content was determined by the spectrophotometric method. Sugars, organic acids, and water-soluble vitamins content were determined using a high-performance liquid chromatography (HPLC) instrument. By solar drying the jujube fruit, the glucose and sucrose content of the fruit decreased, while the fructose content increased. While the initial fructose content was 242.6±4.3, solar drying increased to 256.9±4.0. There was a decrease in glucose, fructose and sucrose contents in jujube fruits dried by tray drying process. It was determined that the organic acid and water-soluble vitamin content of jujube fruit decreased in both solar and tray drying processes. Among the water-soluble vitamins, the highest loss was observed in ascorbic acid and pyridoxine. It was determined that the jujube fruit, whose initial ascorbic acid content was 71.2±0.5, decreased to 9.6±0.1 and 12.1±0.2 values as a result of drying in the solar and on the tray, respectively. On the other hand, solar drying resulted in a greater reduction in vitamin content compared to tray drying.