The influence of pretreatments on the convective drying of pumpkin pieces (Cucurbita maxima) at different air temperatures
2015
Mitić, Nebojša Č. (Faculty of Technology, Leskovac (Serbia)) | Stojiljković, Staniša T. (Faculty of Technology, Leskovac (Serbia)) | Stojiljković, Dragan T. (Faculty of Technology, Leskovac (Serbia)) | Ranđelović, Dejan M. (Faculty of Technology, Leskovac (Serbia)) | Todorović, Bratislav Ž. (Faculty of Technology, Leskovac (Serbia)) | Mitić, Nataša Č. (Faculty of Sport and Physical Education, Niš (Serbia))
In this paper the effects of pretreatment on convective drying of pumpkin (Cucurbita maxima) at air temperature of 55 °C and 65 °C was presended. Three series of blanching in hot water were performed, with the addition of vitamin C, 1 % (pretreatment I), potassiummetabisulfite, 0.3 % (II) and without additions (control sample). The moisture content in raw pumpkin was 89.13 %, while in dried material, moisture content ranged from 10.46 % to 18.25 %. Better preservation of pumpkin pieces was achieved by conduction drying at air temperature of 55 °C, which was proved by the rehydration degree, which achieved values of 93.08 % (pretreatment I), 79.95 % (II) and 96.23 % (control). The rehydration degree reached the following values at air temperature of 65 °C: 65.16 %, 62.92 % and 70.82 %, for pretreatment I, II and control sample, respectively. The process of convective drying of pumpkin pieces can be described by the exponential model in the form y=y0+A1exp[-(x/t1)].
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