Changes of Nutritional and Physical Quality Characteristics During Storage of Osmotic Pretreated Apple Before Hot Air Drying and Sensory Evaluation

Abstract

The aim of this research was to increase the application of different osmotic dehydration solutions to decrease the drying time, and decrease the loss of quality after drying and during storage of apples. Sucrose and trehalose solutions with 20 and 50 Brix concentrations were applied. Drying experiments were performed at 50, 60 and 70C using a hot air dryer. Changes in color, water activity, vitamin C, dry matter, total phenol content and mechanical properties were determined with 3-month intervals. Trehalose pretreatments, especially with 50 Brix concentration, generally decreased the drying time. Trehalose pretreatment with 20 Brix had better effects on quality characteristics. Texture of the samples pretreated using 50 Brix sucrose and trehalose stayed more stable just after drying. Lowest change in puncture force was found in 50 Brix trehalose-treated samples even after 12 months. Samples pretreated using 20 Brix trehalose had the higher preference by the panelists. Practical ApplicationsApple drying is rather important because of large production capacity in the world. For reducing quality losses and the cost, osmotic pretreatments and then using cabin or tunnel dryers, which are based on hot air circulating, have been widely used. Usually sucrose, dextrin, glucose have been used for osmotic dehydration implementations to fruits like apple, kiwi and mango, until now. Sucrose implementation is the most successful for fruits and therefore it has widest usage in fruit processing. But there are many disadvantages of using sucrose like caramelization and changes in flavor and viscosity. Our previous research showed that trehalose has rather good effects to improve the quality of dried vegetables such as carrot and potato. The results of this research can also serve as a valuable resource to further researches for utilization of alternative osmotic materials such as trehalose similar to our research to decrease negative effects of drying process.