PRODUCTION OF HEALTHY AND NUTRITIONAL PUMPKIN SNACKS USING DIFFERENT DRYING METHODS: THE EFFECTS OF DIFFERENT PRE-DRYING AND DRYING PROCESS CONDITIONS ON PRODUCT QUALITY CHARACTERISTICS
Project no. 20443 · Status: Kapanmış · 2018
Summary
In this study, in order to transform the pumpkin into a snack form, puff drying process was applied to pumpkin samples in combination with different pre-drying methods. Hot air drying (60 ° C at 1.8 m / s air velocity), freeze drying (0.15 mbar vacuum pressure and -55 ° C) and osmotic dehydration (66% sucrose solution concentration and 30 ° C) were performed as pre-drying. In the study, after the pre-drying process, the pumpkin samples were reduced to the targeted moisture content of 65, 55 and 45% and then puff-dried. In addition, hot air drying at 1.8 m / s air velocity at 50 ° C, 60 ° C and 70 ° C and freeze-drying at -55 ° C under vacuum pressure of 0.1 mbar, 0.15 mbar, and 0.2 mbar were applied to pumpkin samples and the comparison of the application of each drying method in combination with the puff drying method. As a result of the study, moisture content, water activity, bulk density, rehydration rate, expansion rate, color characteristics (L *, a *, b *, Hue, Chroma, BI and ?E), antioxidant activity (total phenolic content and % DPPH inhibition), crude fiber content, total carotenoid amount, textural and sensory properties were determined. In the drying process, the pumpkin samples were dried at an puffing temperature of 90 ° C, an puffing pressure of 1.9 bar, an puffing time of 10 minutes and a vacuum drying temperature of 70 ° C until the final sample moisture was below 10%. In general, the best results have been achieved in samples which hot air drying and puff drying are combined. In addition, it was found that hot air samples had better crispness results when compared with freeze-dried samples.