Drying characteristics of pumpkin (Cucurbita moschata) slices in convective and freeze dryer

Küçük Resim Yok

Tarih

2017

Dergi Başlığı

Dergi ISSN

Cilt Başlığı

Yayıncı

Springer

Erişim Hakkı

info:eu-repo/semantics/closedAccess

Özet

This study was intended to determine the drying and rehydration kinetics of convective and freeze dried pumpkin slices (0.5 x 3.5 x 0.5 cm). A pilot scale tray drier (at 80 +/- 2 degrees C inlet temperature, 1 m s(-1) air velocity) and freeze drier (13.33 kPa absolute pressure, condenser temperature of -48 +/- 2 degrees C) were used for the drying experiments. Drying curves were fitted to six well-known thin layer drying models. Nonlinear regression analysis was used to evaluate the parameters of the selected models by using statistical software SPSS 16.0 (SPSS Inc., USA). For the convective and freeze drying processes of pumpkin slices, the highest R-2 values, and the lowest RMSE as well as chi(2) values were obtained from Page model. The effective moisture diffusivity (D-eff) of the convective and freeze dried pumpkin slices were obtained from the Fick's diffusion model, and they were found to be 2.233 x 10(-7) and 3.040 x 10(-9) m(2)s(-1), respectively. Specific moisture extraction rate, moisture extraction rate, and specific energy consumption values were almost twice in freeze drying process. Depending on the results, moisture contents and water activity values of pumpkin slices were in acceptable limits for safe storage of products. The rehydration behaviour of [at 18 +/- 2 and 100 +/- 2 degrees C for 1:25, 1:50, 1:75, 1:100, and 1:125 solid:liquid ratios (w:w)] dried pumpkin slices was determined by Peleg's model with the highest R-2. The highest total soluble solid loss of pumpkin slices was observed for the rehydration experiment which performed at 1:25 solid: liquid ratio (w:w). Rehydration ratio of freeze dried slices was found 2-3 times higher than convective dried slices.

Açıklama

Anahtar Kelimeler

Kaynak

Heat and Mass Transfer

WoS Q Değeri

Q3

Scopus Q Değeri

Q2

Cilt

53

Sayı

6

Künye