Effect of Drying Methods on Physico-Chemical And Sensory Characteristics of Osmo-Dehydrated Guava Slices

Abstract

The main objective of this study was to compare the pre-treated guava slices (Psidium guajava L.) dried by different drying methods (tray drying and microwave oven drying) and its quality evaluation. Fresh guava were washed and cut into pieces of 3.5 mm thickness having 65 gm weight. These slices were osmotically dehydrated in different solution concentration (30, 40 & 50°B),process temperature(35 & 45°C),solution to sample ratio (10:1) and Immersion time (120 Minutes).The pretreated samples were dried in tray dryer at 65°C (tray drying) and 20W (n1icrowave drying). It can be concluded from this study that solution temperature, sugar concentration and duration of osmosis were the most pronounced factors affecting solid gain and water loss of guava slices during osmotic dehydration. From the study it can be seen that tray drying of 5 hrs at 65°C is sufficient to achieve a desirable physico-chemical properties of guava slices. But there were slight decrease of values due to variation in syrup temperature and concentration. In case of microwave drying at 20 W for 15 minute it was also found to achieve desirable physico-chemical properties but the values found were slight higher than those dried by tray dryer. The overall acceptability was found to be higher for tray dryer for 45°C at 50°B (syrup ten1perature and concentration) than those of microwave because bwnt spots \Vere found in osn1o-microwave dried samples and also there was non-uniforn1ity drying